diff --git a/packages/astro/test/0-css.test.js b/packages/astro/test/0-css.nodetest.js
similarity index 63%
rename from packages/astro/test/0-css.test.js
rename to packages/astro/test/0-css.nodetest.js
index c8c5af6d8f..4cc1d18645 100644
--- a/packages/astro/test/0-css.test.js
+++ b/packages/astro/test/0-css.nodetest.js
@@ -4,7 +4,8 @@
  * rather than trying to start up when all other threads are busy and having to fight for resources
  */
 
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, it, after } from 'node:test';
 import * as cheerio from 'cheerio';
 import { loadFixture } from './test-utils.js';
 
@@ -22,18 +23,22 @@ describe('CSS', function () {
 		let html;
 		let bundledCSS;
 
-		before(async () => {
-			this.timeout(45000); // test needs a little more time in CI
-			await fixture.build();
+		before(
+			async () => {
+				await fixture.build();
 
-			// get bundled CSS (will be hashed, hence DOM query)
-			html = await fixture.readFile('/index.html');
-			$ = cheerio.load(html);
-			const bundledCSSHREF = $('link[rel=stylesheet][href^=/_astro/]').attr('href');
-			bundledCSS = (await fixture.readFile(bundledCSSHREF.replace(/^\/?/, '/')))
-				.replace(/\s/g, '')
-				.replace('/n', '');
-		});
+				// get bundled CSS (will be hashed, hence DOM query)
+				html = await fixture.readFile('/index.html');
+				$ = cheerio.load(html);
+				const bundledCSSHREF = $('link[rel=stylesheet][href^=/_astro/]').attr('href');
+				bundledCSS = (await fixture.readFile(bundledCSSHREF.replace(/^\/?/, '/')))
+					.replace(/\s/g, '')
+					.replace('/n', '');
+			},
+			{
+				timeout: 45000,
+			}
+		);
 
 		describe('Astro Styles', () => {
 			it('HTML and CSS scoped correctly', async () => {
@@ -53,24 +58,24 @@ describe('CSS', function () {
 				}
 
 				// 1. check HTML
-				expect(el1.attr('class')).to.equal(`blue`);
-				expect(el2.attr('class')).to.equal(`visible`);
+				assert.equal(el1.attr('class'), `blue`);
+				assert.equal(el2.attr('class'), `visible`);
 
 				// 2. check CSS
 				const expected = `.blue[${scopedAttribute}],.color\\:blue[${scopedAttribute}]{color:#b0e0e6}.visible[${scopedAttribute}]{display:block}`;
-				expect(bundledCSS).to.include(expected);
+				assert.equal(bundledCSS.includes(expected), true);
 			});
 
 			it('Generated link tags are void elements', async () => {
-				expect(html).to.not.include('</link>');
+				assert.notEqual(html.includes('</link>'), true);
 			});
 
 			it('No <style> skips scoping', async () => {
 				// Astro component without <style> should not include scoped class
-				expect($('#no-scope').attr('class')).to.equal(undefined);
+				assert.equal($('#no-scope').attr('class'), undefined);
 			});
 
-			it('Child inheritance', (done) => {
+			it('Child inheritance', (t, done) => {
 				for (const [key] of Object.entries($('#passed-in')[0].attribs)) {
 					if (/^data-astro-cid-[A-Za-z\d-]+/.test(key)) {
 						done();
@@ -80,29 +85,29 @@ describe('CSS', function () {
 
 			it('Using hydrated components adds astro-island styles', async () => {
 				const inline = $('style').html();
-				expect(inline).to.include('display:contents');
+				assert.equal(inline.includes('display:contents'), true);
 			});
 
 			it('<style lang="sass">', async () => {
-				expect(bundledCSS).to.match(/h1\[data-astro-cid-[^{]*\{color:#90ee90\}/);
+				assert.match(bundledCSS, /h1\[data-astro-cid-[^{]*\{color:#90ee90\}/);
 			});
 
 			it('<style lang="scss">', async () => {
-				expect(bundledCSS).to.match(/h1\[data-astro-cid-[^{]*\{color:#ff69b4\}/);
+				assert.match(bundledCSS, /h1\[data-astro-cid-[^{]*\{color:#ff69b4\}/);
 			});
 		});
 
 		describe('Styles in src/', () => {
 			it('.css', async () => {
-				expect(bundledCSS).to.match(/.linked-css[^{]*\{color:gold/);
+				assert.match(bundledCSS, /.linked-css[^{]*\{color:gold/);
 			});
 
 			it('.sass', async () => {
-				expect(bundledCSS).to.match(/.linked-sass[^{]*\{color:#789/);
+				assert.match(bundledCSS, /.linked-sass[^{]*\{color:#789/);
 			});
 
 			it('.scss', async () => {
-				expect(bundledCSS).to.match(/.linked-scss[^{]*\{color:#6b8e23/);
+				assert.match(bundledCSS, /.linked-scss[^{]*\{color:#6b8e23/);
 			});
 		});
 
@@ -110,9 +115,9 @@ describe('CSS', function () {
 			it('.css', async () => {
 				const el = $('#react-css');
 				// 1. check HTML
-				expect(el.attr('class')).to.include('react-title');
+				assert.equal(el.attr('class'), 'react-title');
 				// 2. check CSS
-				expect(bundledCSS).to.include('.react-title');
+				assert.equal(bundledCSS.includes('.react-title'), true);
 			});
 
 			it('.module.css', async () => {
@@ -121,30 +126,30 @@ describe('CSS', function () {
 				const moduleClass = classes.find((name) => /^_title_[\w-]+/.test(name));
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include(moduleClass);
+				assert.equal(el.attr('class').includes(moduleClass), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(new RegExp(`.${moduleClass}[^{]*{font-family:fantasy`));
+				assert.match(bundledCSS, new RegExp(`.${moduleClass}[^{]*{font-family:fantasy`));
 			});
 
 			it('.sass', async () => {
 				const el = $('#react-sass');
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include('react-sass-title');
+				assert.equal(el.attr('class').includes('react-sass-title'), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(/.react-sass-title[^{]*\{font-family:fantasy/);
+				assert.match(bundledCSS, /.react-sass-title[^{]*\{font-family:fantasy/);
 			});
 
 			it('.scss', async () => {
 				const el = $('#react-scss');
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include('react-scss-title');
+				assert.equal(el.attr('class').includes('react-scss-title'), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(/.react-scss-title[^{]*\{font-family:fantasy/);
+				assert.match(bundledCSS, /.react-scss-title[^{]*\{font-family:fantasy/);
 			});
 
 			it('.module.sass', async () => {
@@ -153,10 +158,10 @@ describe('CSS', function () {
 				const moduleClass = classes.find((name) => /^_title_[\w-]+/.test(name));
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include(moduleClass);
+				assert.equal(el.attr('class').includes(moduleClass), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(new RegExp(`.${moduleClass}[^{]*{font-family:fantasy`));
+				assert.match(bundledCSS, new RegExp(`.${moduleClass}[^{]*{font-family:fantasy`));
 			});
 
 			it('.module.scss', async () => {
@@ -165,19 +170,19 @@ describe('CSS', function () {
 				const moduleClass = classes.find((name) => /^_title_[\w-]+/.test(name));
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include(moduleClass);
+				assert.equal(el.attr('class').includes(moduleClass), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(new RegExp(`.${moduleClass}[^{]*{font-family:fantasy`));
+				assert.match(bundledCSS, new RegExp(`.${moduleClass}[^{]*{font-family:fantasy`));
 			});
 
 			it('.module.css ordering', () => {
 				const globalStyleClassIndex = bundledCSS.indexOf('.module-ordering');
 				const moduleStyleClassIndex = bundledCSS.indexOf('._module_ordering');
 				// css module has higher priority than global style
-				expect(globalStyleClassIndex).to.be.greaterThan(-1);
-				expect(moduleStyleClassIndex).to.be.greaterThan(-1);
-				expect(moduleStyleClassIndex).to.be.greaterThan(globalStyleClassIndex);
+				assert.equal(globalStyleClassIndex > -1, true);
+				assert.equal(moduleStyleClassIndex > -1, true);
+				assert.equal(moduleStyleClassIndex > globalStyleClassIndex, true);
 			});
 		});
 
@@ -186,10 +191,10 @@ describe('CSS', function () {
 				const el = $('#vue-css');
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include('vue-css');
+				assert.equal(el.attr('class').includes('vue-css'), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(/.vue-css[^{]*\{font-family:cursive/);
+				assert.match(bundledCSS, /.vue-css[^{]*\{font-family:cursive/);
 			});
 
 			it('<style scoped>', async () => {
@@ -198,13 +203,13 @@ describe('CSS', function () {
 				// find data-v-* attribute (how Vue CSS scoping works)
 				const { attribs } = el.get(0);
 				const scopeId = Object.keys(attribs).find((k) => k.startsWith('data-v-'));
-				expect(scopeId).to.be.ok;
+				assert.ok(scopeId);
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include('vue-scoped');
+				assert.equal(el.attr('class').includes('vue-scoped'), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.include(`.vue-scoped[${scopeId}]`);
+				assert.equal(bundledCSS.includes(`.vue-scoped[${scopeId}]`), true);
 			});
 
 			it('<style module>', async () => {
@@ -213,30 +218,30 @@ describe('CSS', function () {
 				const moduleClass = classes.find((name) => /^_title_[\w-]+/.test(name));
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include(moduleClass);
+				assert.equal(el.attr('class').includes(moduleClass), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(new RegExp(`.${moduleClass}[^{]*{font-family:cursive`));
+				assert.match(bundledCSS, new RegExp(`.${moduleClass}[^{]*{font-family:cursive`));
 			});
 
 			it('<style lang="sass">', async () => {
 				const el = $('#vue-sass');
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include('vue-sass');
+				assert.equal(el.attr('class').includes('vue-sass'), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(/.vue-sass[^{]*\{font-family:cursive/);
+				assert.match(bundledCSS, /.vue-sass[^{]*\{font-family:cursive/);
 			});
 
 			it('<style lang="scss">', async () => {
 				const el = $('#vue-scss');
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include('vue-scss');
+				assert.equal(el.attr('class').includes('vue-scss'), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(/.vue-scss[^{]*\{font-family:cursive/);
+				assert.match(bundledCSS, /.vue-scss[^{]*\{font-family:cursive/);
 			});
 		});
 
@@ -249,10 +254,11 @@ describe('CSS', function () {
 				);
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include('svelte-css');
+				assert.equal(el.attr('class').includes('svelte-css'), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(
+				assert.match(
+					bundledCSS,
 					new RegExp(`.svelte-css.${scopedClass}[^{]*{font-family:ComicSansMS`)
 				);
 			});
@@ -265,10 +271,11 @@ describe('CSS', function () {
 				);
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include('svelte-sass');
+				assert.equal(el.attr('class').includes('svelte-sass'), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(
+				assert.match(
+					bundledCSS,
 					new RegExp(`.svelte-sass.${scopedClass}[^{]*{font-family:ComicSansMS`)
 				);
 			});
@@ -281,10 +288,11 @@ describe('CSS', function () {
 				);
 
 				// 1. check HTML
-				expect(el.attr('class')).to.include('svelte-scss');
+				assert.equal(el.attr('class').includes('svelte-scss'), true);
 
 				// 2. check CSS
-				expect(bundledCSS).to.match(
+				assert.match(
+					bundledCSS,
 					new RegExp(`.svelte-scss.${scopedClass}[^{]*{font-family:ComicSansMS`)
 				);
 			});
@@ -300,15 +308,15 @@ describe('CSS', function () {
 				const ssrHtmlCssHref = $ssrHtml('link[rel=stylesheet][href^=/_astro/]').attr('href');
 				const ssrHtmlCss = await fixture.readFile(ssrHtmlCssHref.replace(/^\/?/, '/'));
 
-				expect(onlyHtmlCss).to.include('.svelte-only-and-ssr');
-				expect(ssrHtmlCss).to.include('.svelte-only-and-ssr');
+				assert.equal(onlyHtmlCss.includes('.svelte-only-and-ssr'), true);
+				assert.equal(ssrHtmlCss.includes('.svelte-only-and-ssr'), true);
 			});
 		});
 
 		describe('Vite features', () => {
 			it('.css?raw return a string', () => {
 				const el = $('#css-raw');
-				expect(el.text()).to.equal('.foo {color: red;}');
+				assert.equal(el.text(), '.foo {color: red;}');
 			});
 		});
 	});
@@ -330,7 +338,7 @@ describe('CSS', function () {
 
 		it('resolves CSS in public/', async () => {
 			const href = $('link[href="/global.css"]').attr('href');
-			expect((await fixture.fetch(href)).status).to.equal(200);
+			assert.equal((await fixture.fetch(href)).status, 200);
 		});
 
 		// Skipped until upstream fix lands
@@ -339,25 +347,25 @@ describe('CSS', function () {
 		// Next Vite PR: https://github.com/vitejs/vite/pull/5796
 		it.skip('resolved imported CSS with ?url', async () => {
 			const href = $('link[href$="imported-url.css"]').attr('href');
-			expect(href).to.be.ok;
-			expect((await fixture.fetch(href)).status).to.equal(200);
+			assert.ok(href);
+			assert.equal((await fixture.fetch(href)).status, 200);
 		});
 
 		it('resolves ESM style imports', async () => {
 			const allInjectedStyles = $('style').text().replace(/\s*/g, '');
 
-			expect(allInjectedStyles, 'styles/imported-url.css').to.contain('.imported{');
-			expect(allInjectedStyles, 'styles/imported-url.sass').to.contain('.imported-sass{');
-			expect(allInjectedStyles, 'styles/imported-url.scss').to.contain('.imported-scss{');
+			assert.equal(allInjectedStyles.includes('.imported{'), true, 'styles/imported-url.css');
+			assert.equal(allInjectedStyles.includes('.imported-sass{'), true, 'styles/imported-url.sass');
+			assert.equal(allInjectedStyles.includes('.imported-scss{'), true, 'styles/imported-url.scss');
 		});
 
 		it('resolves Astro styles', async () => {
 			const allInjectedStyles = $('style').text();
 
-			expect(allInjectedStyles).to.contain('.linked-css[data-astro-cid-');
-			expect(allInjectedStyles).to.contain('.linked-sass[data-astro-cid-');
-			expect(allInjectedStyles).to.contain('.linked-scss[data-astro-cid-');
-			expect(allInjectedStyles).to.contain('.wrapper[data-astro-cid-');
+			assert.equal(allInjectedStyles.includes('.linked-css[data-astro-cid-'), true);
+			assert.equal(allInjectedStyles.includes('.linked-sass[data-astro-cid-'), true);
+			assert.equal(allInjectedStyles.includes('.linked-scss[data-astro-cid-'), true);
+			assert.equal(allInjectedStyles.includes('.wrapper[data-astro-cid-'), true);
 		});
 
 		it('resolves Styles from React', async () => {
@@ -368,44 +376,44 @@ describe('CSS', function () {
 			];
 			for (const style of styles) {
 				const href = $(`style[data-vite-dev-id$="${style}"]`).attr('data-vite-dev-id');
-				expect((await fixture.fetch(href)).status, style).to.equal(200);
+				assert.equal((await fixture.fetch(href)).status, 200);
 			}
 
 			const allInjectedStyles = $('style').text().replace(/\s*/g, '');
 
-			expect(allInjectedStyles).to.contain('.react-title{');
-			expect(allInjectedStyles).to.contain('.react-sass-title{');
-			expect(allInjectedStyles).to.contain('.react-scss-title{');
+			assert.equal(allInjectedStyles.includes('.react-title{'), true);
+			assert.equal(allInjectedStyles.includes('.react-sass-title{'), true);
+			assert.equal(allInjectedStyles.includes('.react-scss-title{'), true);
 		});
 
 		it('resolves CSS from Svelte', async () => {
 			const allInjectedStyles = $('style').text();
 
-			expect(allInjectedStyles).to.contain('.svelte-css');
-			expect(allInjectedStyles).to.contain('.svelte-sass');
-			expect(allInjectedStyles).to.contain('.svelte-scss');
+			assert.equal(allInjectedStyles.includes('.svelte-css'), true);
+			assert.equal(allInjectedStyles.includes('.svelte-sass'), true);
+			assert.equal(allInjectedStyles.includes('.svelte-scss'), true);
 		});
 
 		it('resolves CSS from Vue', async () => {
 			const styles = ['VueModules.vue?vue&type=style&index=0&lang.module.scss'];
 			for (const style of styles) {
 				const href = $(`link[href$="${style}"]`).attr('href');
-				expect((await fixture.fetch(href)).status, style).to.equal(200);
+				assert.equal((await fixture.fetch(href)).status, 200, style);
 			}
 
 			const allInjectedStyles = $('style').text().replace(/\s*/g, '');
 
-			expect(allInjectedStyles).to.contain('.vue-css{');
-			expect(allInjectedStyles).to.contain('.vue-sass{');
-			expect(allInjectedStyles).to.contain('.vue-scss{');
-			expect(allInjectedStyles).to.contain('.vue-scoped[data-v-');
+			assert.equal(allInjectedStyles.includes('.vue-css{'), true);
+			assert.equal(allInjectedStyles.includes('.vue-sass{'), true);
+			assert.equal(allInjectedStyles.includes('.vue-scss{'), true);
+			assert.equal(allInjectedStyles.includes('.vue-scoped[data-v-'), true);
 		});
 
 		it('remove unused styles from client:load components', async () => {
 			const bundledAssets = await fixture.readdir('./_astro');
 			// SvelteDynamic styles is already included in the main page css asset
 			const unusedCssAsset = bundledAssets.find((asset) => /SvelteDynamic\..*\.css/.test(asset));
-			expect(unusedCssAsset, 'Found unused style ' + unusedCssAsset).to.be.undefined;
+			assert.equal(unusedCssAsset, undefined, 'Found unused style ' + unusedCssAsset);
 
 			let foundVitePreloadCSS = false;
 			const bundledJS = await fixture.glob('**/*.?(m)js');
@@ -415,7 +423,8 @@ describe('CSS', function () {
 					foundVitePreloadCSS = filename;
 				}
 			}
-			expect(foundVitePreloadCSS).to.equal(
+			assert.equal(
+				foundVitePreloadCSS,
 				false,
 				'Should not have found a preload for the dynamic CSS'
 			);
@@ -427,14 +436,14 @@ describe('CSS', function () {
 			const globalStyleClassIndex = globalStyleTag.index();
 			const moduleStyleClassIndex = moduleStyleTag.index();
 			// css module has higher priority than global style
-			expect(globalStyleClassIndex).to.be.greaterThan(-1);
-			expect(moduleStyleClassIndex).to.be.greaterThan(-1);
-			expect(moduleStyleClassIndex).to.be.greaterThan(globalStyleClassIndex);
+			assert.equal(globalStyleClassIndex > -1, true);
+			assert.equal(moduleStyleClassIndex > -1, true);
+			assert.equal(moduleStyleClassIndex > globalStyleClassIndex, true);
 		});
 
 		it('.css?raw return a string', () => {
 			const el = $('#css-raw');
-			expect(el.text()).to.equal('.foo {color: red;}');
+			assert.equal(el.text(), '.foo {color: red;}');
 		});
 	});
 });
diff --git a/packages/astro/test/cli.nodetest.js b/packages/astro/test/cli.nodetest.js
new file mode 100644
index 0000000000..6a88b5b5d9
--- /dev/null
+++ b/packages/astro/test/cli.nodetest.js
@@ -0,0 +1,204 @@
+import assert from 'node:assert/strict';
+import { describe, it } from 'node:test';
+import { cli, parseCliDevStart, cliServerLogSetup, loadFixture } from './test-utils.js';
+import stripAnsi from 'strip-ansi';
+import { promises as fs, readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { isIPv4 } from 'node:net';
+import { join } from 'node:path';
+import { Writable } from 'node:stream';
+
+describe('astro cli', () => {
+	const cliServerLogSetupWithFixture = (flags, cmd) => {
+		const projectRootURL = new URL('./fixtures/astro-basic/', import.meta.url);
+		return cliServerLogSetup(['--root', fileURLToPath(projectRootURL), ...flags], cmd);
+	};
+
+	it('astro', async () => {
+		const proc = await cli();
+		assert.equal(proc.exitCode, 0);
+	});
+
+	// Flaky test, in CI it exceeds the timeout most of the times
+	it.skip(
+		'astro check --watch reports errors on modified files',
+		{
+			timeout: 35000,
+		},
+		async () => {
+			let messageResolve;
+			const messagePromise = new Promise((resolve) => {
+				messageResolve = resolve;
+			});
+			const oneErrorContent = 'foobar';
+
+			/** @type {import('./test-utils').Fixture} */
+			const fixture = await loadFixture({
+				root: './fixtures/astro-check-watch/',
+			});
+			const logs = [];
+
+			const checkServer = await fixture.check({
+				flags: { watch: true },
+				logging: {
+					level: 'info',
+					dest: new Writable({
+						objectMode: true,
+						write(event, _, callback) {
+							logs.push({ ...event, message: stripAnsi(event.message) });
+							if (event.message.includes('1 error')) {
+								messageResolve(logs);
+							}
+							callback();
+						},
+					}),
+				},
+			});
+			await checkServer.watch();
+			const pagePath = join(fileURLToPath(fixture.config.root), 'src/pages/index.astro');
+			const pageContent = readFileSync(pagePath, 'utf-8');
+			await fs.writeFile(pagePath, oneErrorContent);
+			const messages = await messagePromise;
+			await fs.writeFile(pagePath, pageContent);
+			await checkServer.stop();
+			const diagnostics = messages.filter(
+				(m) => m.type === 'diagnostics' && m.message.includes('Result')
+			);
+			assert.equal(diagnostics[0].message.includes('0 errors'), true);
+			assert.equal(diagnostics[1].message.includes('1 error'), true);
+		}
+	);
+
+	it('astro --version', async () => {
+		const pkgURL = new URL('../package.json', import.meta.url);
+		const pkgVersion = await fs.readFile(pkgURL, 'utf8').then((data) => JSON.parse(data).version);
+
+		const proc = await cli('--version');
+
+		assert.equal(proc.stdout.includes(pkgVersion), true);
+	});
+
+	it(
+		'astro check no errors',
+		{
+			timeout: 35000,
+		},
+		async () => {
+			let proc = undefined;
+			const projectRootURL = new URL('./fixtures/astro-check-no-errors/', import.meta.url);
+			try {
+				proc = await cli('check', '--root', fileURLToPath(projectRootURL));
+			} catch (err) {}
+
+			assert.equal(proc?.stdout.includes('0 errors'), true);
+		}
+	);
+
+	it(
+		'astro check has errors',
+		{
+			timeout: 35000,
+		},
+		async () => {
+			let stdout = undefined;
+			const projectRootURL = new URL('./fixtures/astro-check-errors/', import.meta.url);
+
+			// When `astro check` finds errors, it returns an error code. As such, we need to wrap this
+			// in a try/catch because otherwise Mocha will always report this test as a fail
+			try {
+				await cli('check', '--root', fileURLToPath(projectRootURL));
+			} catch (err) {
+				stdout = err.toString();
+			}
+
+			assert.equal(stdout.includes('1 error'), true);
+		}
+	);
+
+	it('astro dev welcome', async () => {
+		const pkgURL = new URL('../package.json', import.meta.url);
+		const pkgVersion = await fs.readFile(pkgURL, 'utf8').then((data) => JSON.parse(data).version);
+
+		const projectRootURL = new URL('./fixtures/astro-basic/', import.meta.url);
+		const proc = cli('dev', '--root', fileURLToPath(projectRootURL));
+		const { messages } = await parseCliDevStart(proc);
+
+		const index = messages[0].includes('[vite]') ? 1 : 0;
+		assert.equal(messages[index].includes('astro'), true);
+		assert.equal(messages[index].includes(pkgVersion), true);
+		assert.equal(messages[index].includes('ready in'), true);
+	});
+
+	['dev', 'preview'].forEach((cmd) => {
+		const networkLogFlags = [['--host'], ['--host', '0.0.0.0']];
+		networkLogFlags.forEach(([flag, flagValue]) => {
+			it(`astro ${cmd} ${flag} ${flagValue ?? ''} - network log`, async () => {
+				const { local, network } = await cliServerLogSetupWithFixture(
+					flagValue ? [flag, flagValue] : [flag],
+					cmd
+				);
+
+				assert.notEqual(local, undefined);
+				assert.notEqual(network, undefined);
+
+				const localURL = new URL(local);
+				const networkURL = new URL(network);
+
+				assert.equal(['localhost', '127.0.0.1'].includes(localURL.hostname), true),
+					`Expected local URL to be on localhost`;
+
+				// Note: our tests run in parallel so this could be 3000+!
+				assert.equal(Number.parseInt(localURL.port) >= 4321, true, `Expected Port to be >= 4321`);
+				assert.equal(
+					networkURL.port,
+					localURL.port,
+					`Expected local and network ports to be equal`
+				);
+				assert.equal(
+					isIPv4(networkURL.hostname),
+					true,
+					`Expected network URL to respect --host flag`
+				);
+			});
+		});
+
+		const hostToExposeFlags = [['', '']];
+		hostToExposeFlags.forEach(([flag, flagValue]) => {
+			it(`astro ${cmd} ${flag} ${flagValue} - host to expose`, async () => {
+				const { local, network } = await cliServerLogSetupWithFixture([flag, flagValue], cmd);
+
+				assert.notEqual(local, undefined);
+				assert.notEqual(network, undefined);
+				const localURL = new URL(local);
+
+				assert.equal(
+					['localhost', '127.0.0.1'].includes(localURL.hostname),
+					true,
+					`Expected local URL to be on localhost`
+				);
+
+				assert.throws(() => new URL(networkURL));
+			});
+		});
+
+		const noNetworkLogFlags = [
+			['--host', 'localhost'],
+			['--host', '127.0.0.1'],
+		];
+		noNetworkLogFlags.forEach(([flag, flagValue]) => {
+			it(`astro ${cmd} ${flag} ${flagValue} - no network log`, async () => {
+				const { local, network } = await cliServerLogSetupWithFixture([flag, flagValue], cmd);
+
+				assert.notEqual(local, undefined);
+				assert.equal(network, undefined);
+
+				const localURL = new URL(local);
+				assert.equal(
+					['localhost', '127.0.0.1'].includes(localURL.hostname),
+					true,
+					`Expected local URL to be on localhost`
+				);
+			});
+		});
+	});
+});
diff --git a/packages/astro/test/cli.test.js b/packages/astro/test/cli.test.js
deleted file mode 100644
index 8fb375fe96..0000000000
--- a/packages/astro/test/cli.test.js
+++ /dev/null
@@ -1,186 +0,0 @@
-import { expect } from 'chai';
-import { cli, parseCliDevStart, cliServerLogSetup, loadFixture } from './test-utils.js';
-import stripAnsi from 'strip-ansi';
-import { promises as fs, readFileSync } from 'node:fs';
-import { fileURLToPath } from 'node:url';
-import { isIPv4 } from 'node:net';
-import { join } from 'node:path';
-import { Writable } from 'node:stream';
-
-describe('astro cli', () => {
-	const cliServerLogSetupWithFixture = (flags, cmd) => {
-		const projectRootURL = new URL('./fixtures/astro-basic/', import.meta.url);
-		return cliServerLogSetup(['--root', fileURLToPath(projectRootURL), ...flags], cmd);
-	};
-
-	it('astro', async () => {
-		const proc = await cli();
-		expect(proc.exitCode).to.equal(0);
-	});
-
-	// Flaky test, in CI it exceeds the timeout most of the times
-	it.skip('astro check --watch reports errors on modified files', async () => {
-		let messageResolve;
-		const messagePromise = new Promise((resolve) => {
-			messageResolve = resolve;
-		});
-		const oneErrorContent = 'foobar';
-
-		/** @type {import('./test-utils').Fixture} */
-		const fixture = await loadFixture({
-			root: './fixtures/astro-check-watch/',
-		});
-		const logs = [];
-
-		const checkServer = await fixture.check({
-			flags: { watch: true },
-			logging: {
-				level: 'info',
-				dest: new Writable({
-					objectMode: true,
-					write(event, _, callback) {
-						logs.push({ ...event, message: stripAnsi(event.message) });
-						if (event.message.includes('1 error')) {
-							messageResolve(logs);
-						}
-						callback();
-					},
-				}),
-			},
-		});
-		await checkServer.watch();
-		const pagePath = join(fileURLToPath(fixture.config.root), 'src/pages/index.astro');
-		const pageContent = readFileSync(pagePath, 'utf-8');
-		await fs.writeFile(pagePath, oneErrorContent);
-		const messages = await messagePromise;
-		await fs.writeFile(pagePath, pageContent);
-		await checkServer.stop();
-		const diagnostics = messages.filter(
-			(m) => m.type === 'diagnostics' && m.message.includes('Result')
-		);
-		expect(diagnostics[0].message).to.include('0 errors');
-		expect(diagnostics[1].message).to.include('1 error');
-	}).timeout(35000);
-
-	it('astro --version', async () => {
-		const pkgURL = new URL('../package.json', import.meta.url);
-		const pkgVersion = await fs.readFile(pkgURL, 'utf8').then((data) => JSON.parse(data).version);
-
-		const proc = await cli('--version');
-
-		expect(proc.stdout).to.include(pkgVersion);
-	});
-
-	it('astro check no errors', async () => {
-		let proc = undefined;
-		const projectRootURL = new URL('./fixtures/astro-check-no-errors/', import.meta.url);
-		try {
-			proc = await cli('check', '--root', fileURLToPath(projectRootURL));
-		} catch (err) {}
-
-		expect(proc?.stdout).to.include('0 errors');
-	}).timeout(35000);
-
-	it('astro check has errors', async () => {
-		let stdout = undefined;
-		const projectRootURL = new URL('./fixtures/astro-check-errors/', import.meta.url);
-
-		// When `astro check` finds errors, it returns an error code. As such, we need to wrap this
-		// in a try/catch because otherwise Mocha will always report this test as a fail
-		try {
-			await cli('check', '--root', fileURLToPath(projectRootURL));
-		} catch (err) {
-			stdout = err.toString();
-		}
-
-		expect(stdout).to.include('1 error');
-	}).timeout(35000);
-
-	it('astro dev welcome', async () => {
-		const pkgURL = new URL('../package.json', import.meta.url);
-		const pkgVersion = await fs.readFile(pkgURL, 'utf8').then((data) => JSON.parse(data).version);
-
-		const projectRootURL = new URL('./fixtures/astro-basic/', import.meta.url);
-		const proc = cli('dev', '--root', fileURLToPath(projectRootURL));
-		const { messages } = await parseCliDevStart(proc);
-
-		const index = messages[0].includes('[vite]') ? 1 : 0;
-		expect(messages[index]).to.contain('astro');
-		expect(messages[index]).to.contain(pkgVersion);
-		expect(messages[index]).to.contain('ready in');
-	});
-
-	['dev', 'preview'].forEach((cmd) => {
-		const networkLogFlags = [['--host'], ['--host', '0.0.0.0']];
-		networkLogFlags.forEach(([flag, flagValue]) => {
-			it(`astro ${cmd} ${flag} ${flagValue ?? ''} - network log`, async () => {
-				const { local, network } = await cliServerLogSetupWithFixture(
-					flagValue ? [flag, flagValue] : [flag],
-					cmd
-				);
-
-				expect(local).to.not.be.undefined;
-				expect(network).to.not.be.undefined;
-
-				const localURL = new URL(local);
-				const networkURL = new URL(network);
-
-				expect(localURL.hostname).to.be.oneOf(
-					['localhost', '127.0.0.1'],
-					`Expected local URL to be on localhost`
-				);
-
-				// Note: our tests run in parallel so this could be 3000+!
-				expect(Number.parseInt(localURL.port)).to.be.greaterThanOrEqual(
-					4321,
-					`Expected Port to be >= 4321`
-				);
-				expect(networkURL.port).to.be.equal(
-					localURL.port,
-					`Expected local and network ports to be equal`
-				);
-				expect(isIPv4(networkURL.hostname)).to.be.equal(
-					true,
-					`Expected network URL to respect --host flag`
-				);
-			});
-		});
-
-		const hostToExposeFlags = [['', '']];
-		hostToExposeFlags.forEach(([flag, flagValue]) => {
-			it(`astro ${cmd} ${flag} ${flagValue} - host to expose`, async () => {
-				const { local, network } = await cliServerLogSetupWithFixture([flag, flagValue], cmd);
-
-				expect(local).to.not.be.undefined;
-				expect(network).to.not.be.undefined;
-				const localURL = new URL(local);
-
-				expect(localURL.hostname).to.be.oneOf(
-					['localhost', '127.0.0.1'],
-					`Expected local URL to be on localhost`
-				);
-
-				expect(() => new URL(networkURL)).to.throw();
-			});
-		});
-
-		const noNetworkLogFlags = [
-			['--host', 'localhost'],
-			['--host', '127.0.0.1'],
-		];
-		noNetworkLogFlags.forEach(([flag, flagValue]) => {
-			it(`astro ${cmd} ${flag} ${flagValue} - no network log`, async () => {
-				const { local, network } = await cliServerLogSetupWithFixture([flag, flagValue], cmd);
-
-				expect(local).to.not.be.undefined;
-				expect(network).to.be.undefined;
-
-				const localURL = new URL(local);
-				expect(localURL.hostname).to.be.oneOf(
-					['localhost', '127.0.0.1'],
-					`Expected local URL to be on localhost`
-				);
-			});
-		});
-	});
-});
diff --git a/packages/astro/test/client-address.test.js b/packages/astro/test/client-address.nodetest.js
similarity index 86%
rename from packages/astro/test/client-address.test.js
rename to packages/astro/test/client-address.nodetest.js
index 339d17ad94..de4a6a4f42 100644
--- a/packages/astro/test/client-address.test.js
+++ b/packages/astro/test/client-address.nodetest.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, it, after } from 'node:test';
 import { loadFixture } from './test-utils.js';
 import testAdapter from './test-adapter.js';
 import * as cheerio from 'cheerio';
@@ -27,7 +28,7 @@ describe('Astro.clientAddress', () => {
 				const response = await app.render(request);
 				const html = await response.text();
 				const $ = cheerio.load(html);
-				expect($('#address').text()).to.equal('0.0.0.0');
+				assert.equal($('#address').text(), '0.0.0.0');
 			});
 
 			it('app.render can provide the address', async () => {
@@ -36,7 +37,7 @@ describe('Astro.clientAddress', () => {
 				const response = await app.render(request, { clientAddress: '1.1.1.1' });
 				const html = await response.text();
 				const $ = cheerio.load(html);
-				expect($('#address').text()).to.equal('1.1.1.1');
+				assert.equal($('#address').text(), '1.1.1.1');
 			});
 		});
 
@@ -54,14 +55,14 @@ describe('Astro.clientAddress', () => {
 
 			it('Gets the address', async () => {
 				let res = await fixture.fetch('/');
-				expect(res.status).to.equal(200);
+				assert.equal(res.status, 200);
 				let html = await res.text();
 				let $ = cheerio.load(html);
 				let address = $('#address');
 
 				// Just checking that something is here. Not specifying address as it
 				// might differ per machine.
-				expect(address.length).to.be.greaterThan(0);
+				assert.equal(address.length > 0, true);
 			});
 		});
 	});
@@ -83,7 +84,7 @@ describe('Astro.clientAddress', () => {
 			const app = await fixture.loadTestAdapterApp();
 			const request = new Request('http://example.com/');
 			const response = await app.render(request);
-			expect(response.status).to.equal(500);
+			assert.equal(response.status, 500);
 		});
 	});
 
@@ -102,9 +103,10 @@ describe('Astro.clientAddress', () => {
 			it('throws during generation', async () => {
 				try {
 					await fixture.build();
-					expect(false).to.equal(true, 'Build should not have completed');
+					assert.equal(false, true, 'Build should not have completed');
 				} catch (err) {
-					expect(err.message).to.match(
+					assert.match(
+						err.message,
 						/Astro\.clientAddress/,
 						'Error message mentions Astro.clientAddress'
 					);
@@ -126,7 +128,7 @@ describe('Astro.clientAddress', () => {
 
 			it('is not accessible', async () => {
 				let res = await fixture.fetch('/');
-				expect(res.status).to.equal(500);
+				assert.equal(res.status, 500);
 			});
 		});
 	});
diff --git a/packages/astro/test/code-component.test.js b/packages/astro/test/code-component.nodetest.js
similarity index 72%
rename from packages/astro/test/code-component.test.js
rename to packages/astro/test/code-component.nodetest.js
index 8481e95d8a..a3ed65088e 100644
--- a/packages/astro/test/code-component.test.js
+++ b/packages/astro/test/code-component.nodetest.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import { loadFixture } from './test-utils.js';
 
@@ -14,20 +15,20 @@ describe('Code component', () => {
 	it('Debug component styles are not included in the page', async () => {
 		let html = await fixture.readFile('/index.html');
 		let $ = cheerio.load(html);
-		expect($('link[rel=stylesheet]')).to.have.a.lengthOf(0, 'No styles should be built');
-		expect($('style')).to.have.a.lengthOf(0);
+		assert.equal($('link[rel=stylesheet]').length, 0, 'No styles should be built');
+		assert.equal($('style').length, 0);
 	});
 
 	it('is:raw attribute not serialized', async () => {
 		let html = await fixture.readFile('/index.html');
 		let $ = cheerio.load(html);
-		expect($('pre').attr('is:raw')).to.equal(undefined);
+		assert.equal($('pre').attr('is:raw'), undefined);
 	});
 
 	// ViewTransitions bug
 	it('No script should be added to the page', async () => {
 		let html = await fixture.readFile('/index.html');
 		let $ = cheerio.load(html);
-		expect($('script')).to.have.a.lengthOf(0);
+		assert.equal($('script').length, 0);
 	});
 });
diff --git a/packages/astro/test/component-library.test.js b/packages/astro/test/component-library.nodetest.js
similarity index 73%
rename from packages/astro/test/component-library.test.js
rename to packages/astro/test/component-library.nodetest.js
index a135c40cb5..9533509d63 100644
--- a/packages/astro/test/component-library.test.js
+++ b/packages/astro/test/component-library.nodetest.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, it, after } from 'node:test';
 import { load as cheerioLoad } from 'cheerio';
 import { loadFixture } from './test-utils.js';
 
@@ -43,23 +44,24 @@ describe('Component Libraries', () => {
 
 		it('Built .astro pages', async () => {
 			let html = await fixture.readFile('/with-astro/index.html');
-			expect(html).to.be.a('string');
+			assert.equal(typeof html, 'string');
 
 			html = await fixture.readFile('/with-react/index.html');
-			expect(html).to.be.a('string');
+			assert.equal(typeof html, 'string');
 
 			html = await fixture.readFile('/internal-hydration/index.html');
-			expect(html).to.be.a('string');
+			assert.equal(typeof html, 'string');
 		});
 
 		it('Works with .astro components', async () => {
 			const html = await fixture.readFile('/with-astro/index.html');
 			const $ = cheerioLoad(html);
 
-			expect($('button').text()).to.equal('Click me', "Rendered the component's slot");
+			assert.equal($('button').text(), 'Click me', "Rendered the component's slot");
 
 			const findEvidence = createFindEvidence(/border-radius:\s*1rem/);
-			expect(await findEvidence('with-astro/index.html')).to.equal(
+			assert.equal(
+				await findEvidence('with-astro/index.html'),
 				true,
 				"Included the .astro component's <style>"
 			);
@@ -69,27 +71,29 @@ describe('Component Libraries', () => {
 			const html = await fixture.readFile('/with-react/index.html');
 			const $ = cheerioLoad(html);
 
-			expect($('#react-static').text()).to.equal('Hello static!', 'Rendered the static component');
+			assert.equal($('#react-static').text(), 'Hello static!', 'Rendered the static component');
 
-			expect($('#react-idle').text()).to.equal(
+			assert.equal(
+				$('#react-idle').text(),
 				'Hello idle!',
 				'Rendered the client hydrated component'
 			);
 
-			expect($('astro-island[uid]')).to.have.lengthOf(1, 'Included one hydration island');
+			assert.equal($('astro-island[uid]').length, 1, 'Included one hydration island');
 		});
 
 		it('Works with components hydrated internally', async () => {
 			const html = await fixture.readFile('/internal-hydration/index.html');
 			const $ = cheerioLoad(html);
 
-			expect($('.counter').length).to.equal(1, 'Rendered the svelte counter');
-			expect($('.counter-message').text().trim()).to.equal(
+			assert.equal($('.counter').length, 1, 'Rendered the svelte counter');
+			assert.equal(
+				$('.counter-message').text().trim(),
 				'Hello, Svelte!',
 				"rendered the counter's slot"
 			);
 
-			expect($('astro-island[uid]')).to.have.lengthOf(1, 'Included one hydration island');
+			assert.equal($('astro-island[uid]').length, 1, 'Included one hydration island');
 		});
 	});
 
@@ -134,10 +138,11 @@ describe('Component Libraries', () => {
 			const html = await fixture.fetch('/with-astro/').then((res) => res.text());
 			const $ = cheerioLoad(html);
 
-			expect($('button').text()).to.equal('Click me', "Rendered the component's slot");
+			assert.equal($('button').text(), 'Click me', "Rendered the component's slot");
 
 			const findEvidence = createFindEvidence(/border-radius:\s*1rem/);
-			expect(await findEvidence('/with-astro/')).to.equal(
+			assert.equal(
+				await findEvidence('/with-astro/'),
 				true,
 				"Included the .astro component's <style>"
 			);
@@ -147,27 +152,29 @@ describe('Component Libraries', () => {
 			const html = await fixture.fetch('/with-react/').then((res) => res.text());
 			const $ = cheerioLoad(html);
 
-			expect($('#react-static').text()).to.equal('Hello static!', 'Rendered the static component');
+			assert.equal($('#react-static').text(), 'Hello static!', 'Rendered the static component');
 
-			expect($('#react-idle').text()).to.equal(
+			assert.equal(
+				$('#react-idle').text(),
 				'Hello idle!',
 				'Rendered the client hydrated component'
 			);
 
-			expect($('astro-island[uid]')).to.have.lengthOf(1, 'Included one hydration island');
+			assert.equal($('astro-island[uid]').length, 1, 'Included one hydration island');
 		});
 
 		it('Works with components hydrated internally', async () => {
 			const html = await fixture.fetch('/internal-hydration/').then((res) => res.text());
 			const $ = cheerioLoad(html);
 
-			expect($('.counter').length).to.equal(1, 'Rendered the svelte counter');
-			expect($('.counter-message').text().trim()).to.equal(
+			assert.equal($('.counter').length, 1, 'Rendered the svelte counter');
+			assert.equal(
+				$('.counter-message').text().trim(),
 				'Hello, Svelte!',
 				"rendered the counter's slot"
 			);
 
-			expect($('astro-island[uid]')).to.have.lengthOf(1, 'Included one hydration island');
+			assert.equal($('astro-island[uid]').length, 1, 'Included one hydration island');
 		});
 	});
 });
diff --git a/packages/astro/test/config-mode.test.js b/packages/astro/test/config-mode.nodetest.js
similarity index 81%
rename from packages/astro/test/config-mode.test.js
rename to packages/astro/test/config-mode.nodetest.js
index 84dafb81f7..2b5533f4df 100644
--- a/packages/astro/test/config-mode.test.js
+++ b/packages/astro/test/config-mode.nodetest.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, it } from 'node:test';
 import { loadFixture } from './test-utils.js';
 import testAdapter from './test-adapter.js';
 
@@ -22,10 +23,10 @@ describe('AstroConfig - config.output', () => {
 				const app = await fixture.loadTestAdapterApp();
 				const request = new Request('http://example.com/');
 				const response = await app.render(request);
-				expect(response.status).to.equal(200);
-				expect(response.headers.get('content-type')).to.equal('text/html');
+				assert.equal(response.status, 200);
+				assert.equal(response.headers.get('content-type'), 'text/html');
 				const html = await response.text();
-				expect(html.length).to.be.greaterThan(0);
+				assert.equal(html.length > 0, true);
 			});
 		});
 
@@ -47,11 +48,11 @@ describe('AstroConfig - config.output', () => {
 					await fixture.build();
 					built = true;
 				} catch (err) {
-					expect(err).to.be.an.instanceOf(Error);
-					expect(err.message).to.match(/without an adapter/);
+					assert.equal(err instanceof Error, true);
+					assert.match(err.message, /without an adapter/);
 				}
 
-				expect(built).to.equal(false, 'Should not have built');
+				assert.equal(built, false, 'Should not have built');
 			});
 		});
 	});
@@ -75,9 +76,9 @@ describe('AstroConfig - config.output', () => {
 				try {
 					html = await fixture.readFile('/index.html');
 				} catch (err) {
-					expect(false).to.equal(true, 'Couldnt find the file, which mean it did not build.');
+					assert.equal(false, true, 'Couldnt find the file, which mean it did not build.');
 				}
-				expect(html.length).to.be.greaterThan(0);
+				assert.equal(html.length > 0, true);
 			});
 		});
 
diff --git a/packages/astro/test/config-vite-css-target.test.js b/packages/astro/test/config-vite-css-target.nodetest.js
similarity index 83%
rename from packages/astro/test/config-vite-css-target.test.js
rename to packages/astro/test/config-vite-css-target.nodetest.js
index b0cac084fe..97cba273fa 100644
--- a/packages/astro/test/config-vite-css-target.test.js
+++ b/packages/astro/test/config-vite-css-target.nodetest.js
@@ -2,7 +2,8 @@
  * css-target
  */
 
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import { loadFixture } from './test-utils.js';
 
@@ -35,7 +36,7 @@ describe('CSS', function () {
 		});
 
 		it('vite.build.cssTarget is respected', async () => {
-			expect(bundledCSS).to.match(/\.class\[data-astro-[^{]*\{top:0;right:0;bottom:0;left:0\}/);
+			assert.match(bundledCSS, /\.class\[data-astro-[^{]*\{top:0;right:0;bottom:0;left:0\}/);
 		});
 	});
 });
diff --git a/packages/astro/test/config-vite.test.js b/packages/astro/test/config-vite.nodetest.js
similarity index 76%
rename from packages/astro/test/config-vite.test.js
rename to packages/astro/test/config-vite.nodetest.js
index 1b4eaf11c4..24927e9c74 100644
--- a/packages/astro/test/config-vite.test.js
+++ b/packages/astro/test/config-vite.nodetest.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import { loadFixture } from './test-utils.js';
 
@@ -17,6 +18,6 @@ describe('Vite Config', async () => {
 	it('Allows overriding bundle naming options in the build', async () => {
 		const html = await fixture.readFile('/index.html');
 		const $ = cheerio.load(html);
-		expect($('link').attr('href')).to.match(/\/assets\/testing-[a-z\d]+\.css/);
+		assert.match($('link').attr('href'), /\/assets\/testing-[a-z\d]+\.css/);
 	});
 });
diff --git a/packages/astro/test/content-collections.test.js b/packages/astro/test/content-collections.nodetest.js
similarity index 71%
rename from packages/astro/test/content-collections.test.js
rename to packages/astro/test/content-collections.nodetest.js
index 44d08b532e..28c153150c 100644
--- a/packages/astro/test/content-collections.test.js
+++ b/packages/astro/test/content-collections.nodetest.js
@@ -1,6 +1,7 @@
 import * as devalue from 'devalue';
 import * as cheerio from 'cheerio';
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, it } from 'node:test';
 import { loadFixture } from './test-utils.js';
 import testAdapter from './test-adapter.js';
 import { preventNodeBuiltinDependencyPlugin } from './test-plugins.js';
@@ -21,11 +22,11 @@ describe('Content Collections', () => {
 			});
 
 			it('Returns `without config` collection', async () => {
-				expect(json).to.haveOwnProperty('withoutConfig');
-				expect(Array.isArray(json.withoutConfig)).to.equal(true);
+				assert.ok(json.hasOwnProperty('withoutConfig'));
+				assert.equal(Array.isArray(json.withoutConfig), true);
 
 				const ids = json.withoutConfig.map((item) => item.id);
-				expect(ids).to.deep.equal([
+				assert.deepEqual(ids, [
 					'columbia.md',
 					'endeavour.md',
 					'enterprise.md',
@@ -35,11 +36,11 @@ describe('Content Collections', () => {
 			});
 
 			it('Handles spaces in `without config` slugs', async () => {
-				expect(json).to.haveOwnProperty('withoutConfig');
-				expect(Array.isArray(json.withoutConfig)).to.equal(true);
+				assert.ok(json.hasOwnProperty('withoutConfig'));
+				assert.equal(Array.isArray(json.withoutConfig), true);
 
 				const slugs = json.withoutConfig.map((item) => item.slug);
-				expect(slugs).to.deep.equal([
+				assert.deepEqual(slugs, [
 					'columbia',
 					'endeavour',
 					'enterprise',
@@ -49,46 +50,50 @@ describe('Content Collections', () => {
 			});
 
 			it('Returns `with schema` collection', async () => {
-				expect(json).to.haveOwnProperty('withSchemaConfig');
-				expect(Array.isArray(json.withSchemaConfig)).to.equal(true);
+				assert.ok(json.hasOwnProperty('withSchemaConfig'));
+				assert.equal(Array.isArray(json.withSchemaConfig), true);
 
 				const ids = json.withSchemaConfig.map((item) => item.id);
 				const publishedDates = json.withSchemaConfig.map((item) => item.data.publishedAt);
-				expect(ids).to.deep.equal(['four%.md', 'one.md', 'three.md', 'two.md']);
-				expect(publishedDates.every((date) => date instanceof Date)).to.equal(
+				assert.deepEqual(ids, ['four%.md', 'one.md', 'three.md', 'two.md']);
+				assert.equal(
+					publishedDates.every((date) => date instanceof Date),
 					true,
 					'Not all publishedAt dates are Date objects'
 				);
-				expect(publishedDates.map((date) => date.toISOString())).to.deep.equal([
-					'2021-01-01T00:00:00.000Z',
-					'2021-01-01T00:00:00.000Z',
-					'2021-01-03T00:00:00.000Z',
-					'2021-01-02T00:00:00.000Z',
-				]);
+				assert.deepEqual(
+					publishedDates.map((date) => date.toISOString()),
+					[
+						'2021-01-01T00:00:00.000Z',
+						'2021-01-01T00:00:00.000Z',
+						'2021-01-03T00:00:00.000Z',
+						'2021-01-02T00:00:00.000Z',
+					]
+				);
 			});
 
 			it('Returns `with custom slugs` collection', async () => {
-				expect(json).to.haveOwnProperty('withSlugConfig');
-				expect(Array.isArray(json.withSlugConfig)).to.equal(true);
+				assert.ok(json.hasOwnProperty('withSlugConfig'));
+				assert.equal(Array.isArray(json.withSlugConfig), true);
 
 				const slugs = json.withSlugConfig.map((item) => item.slug);
-				expect(slugs).to.deep.equal(['fancy-one', 'excellent-three', 'interesting-two']);
+				assert.deepEqual(slugs, ['fancy-one', 'excellent-three', 'interesting-two']);
 			});
 
 			it('Returns `with union schema` collection', async () => {
-				expect(json).to.haveOwnProperty('withUnionSchema');
-				expect(Array.isArray(json.withUnionSchema)).to.equal(true);
+				assert.ok(json.hasOwnProperty('withUnionSchema'));
+				assert.equal(Array.isArray(json.withUnionSchema), true);
 
 				const post = json.withUnionSchema.find((item) => item.id === 'post.md');
-				expect(post).to.not.be.undefined;
-				expect(post.data).to.deep.equal({
+				assert.notEqual(post, undefined);
+				assert.deepEqual(post.data, {
 					type: 'post',
 					title: 'My Post',
 					description: 'This is my post',
 				});
 				const newsletter = json.withUnionSchema.find((item) => item.id === 'newsletter.md');
-				expect(newsletter).to.not.be.undefined;
-				expect(newsletter.data).to.deep.equal({
+				assert.notEqual(newsletter, undefined);
+				assert.deepEqual(newsletter.data, {
 					type: 'newsletter',
 					subject: 'My Newsletter',
 				});
@@ -99,7 +104,7 @@ describe('Content Collections', () => {
 			it('Applies styles', async () => {
 				const html = await fixture.readFile('/propagation/index.html');
 				const $ = cheerio.load(html);
-				expect($('style').text()).to.include('content:"works!"');
+				assert.equal($('style').text().includes('content:"works!"'), true);
 			});
 		});
 
@@ -111,28 +116,29 @@ describe('Content Collections', () => {
 			});
 
 			it('Returns `without config` collection entry', async () => {
-				expect(json).to.haveOwnProperty('columbiaWithoutConfig');
-				expect(json.columbiaWithoutConfig.id).to.equal('columbia.md');
+				assert.ok(json.hasOwnProperty('columbiaWithoutConfig'));
+				assert.equal(json.columbiaWithoutConfig.id, 'columbia.md');
 			});
 
 			it('Returns `with schema` collection entry', async () => {
-				expect(json).to.haveOwnProperty('oneWithSchemaConfig');
-				expect(json.oneWithSchemaConfig.id).to.equal('one.md');
-				expect(json.oneWithSchemaConfig.data.publishedAt instanceof Date).to.equal(true);
-				expect(json.oneWithSchemaConfig.data.publishedAt.toISOString()).to.equal(
+				assert.ok(json.hasOwnProperty('oneWithSchemaConfig'));
+				assert.equal(json.oneWithSchemaConfig.id, 'one.md');
+				assert.equal(json.oneWithSchemaConfig.data.publishedAt instanceof Date, true);
+				assert.equal(
+					json.oneWithSchemaConfig.data.publishedAt.toISOString(),
 					'2021-01-01T00:00:00.000Z'
 				);
 			});
 
 			it('Returns `with custom slugs` collection entry', async () => {
-				expect(json).to.haveOwnProperty('twoWithSlugConfig');
-				expect(json.twoWithSlugConfig.slug).to.equal('interesting-two');
+				assert.ok(json.hasOwnProperty('twoWithSlugConfig'));
+				assert.equal(json.twoWithSlugConfig.slug, 'interesting-two');
 			});
 
 			it('Returns `with union schema` collection entry', async () => {
-				expect(json).to.haveOwnProperty('postWithUnionSchema');
-				expect(json.postWithUnionSchema.id).to.equal('post.md');
-				expect(json.postWithUnionSchema.data).to.deep.equal({
+				assert.ok(json.hasOwnProperty('postWithUnionSchema'));
+				assert.equal(json.postWithUnionSchema.id, 'post.md');
+				assert.deepEqual(json.postWithUnionSchema.data, {
 					type: 'post',
 					title: 'My Post',
 					description: 'This is my post',
@@ -174,7 +180,7 @@ describe('Content Collections', () => {
 
 		it('Generates expected pages', async () => {
 			for (const slug in blogSlugToContents) {
-				expect(fixture.pathExists(`/posts/${slug}`)).to.equal(true);
+				assert.equal(fixture.pathExists(`/posts/${slug}`), true);
 			}
 		});
 
@@ -182,7 +188,7 @@ describe('Content Collections', () => {
 			for (const slug in blogSlugToContents) {
 				const post = await fixture.readFile(`/posts/${slug}/index.html`);
 				const $ = cheerio.load(post);
-				expect($('h1').text()).to.equal(blogSlugToContents[slug].title);
+				assert.equal($('h1').text(), blogSlugToContents[slug].title);
 			}
 		});
 
@@ -190,7 +196,8 @@ describe('Content Collections', () => {
 			for (const slug in blogSlugToContents) {
 				const post = await fixture.readFile(`/posts/${slug}/index.html`);
 				const $ = cheerio.load(post);
-				expect($(blogSlugToContents[slug].element).text().trim()).to.equal(
+				assert.equal(
+					$(blogSlugToContents[slug].element).text().trim(),
 					blogSlugToContents[slug].content
 				);
 			}
@@ -206,7 +213,7 @@ describe('Content Collections', () => {
 			} catch (e) {
 				error = e.message;
 			}
-			expect(error).to.be.null;
+			assert.equal(error, null);
 		});
 	});
 	describe('With config.mjs', () => {
@@ -220,7 +227,7 @@ describe('Content Collections', () => {
 			} catch (e) {
 				error = e.message;
 			}
-			expect(error).to.include('**title**: Expected type `"string"`, received "number"');
+			assert.equal(error.includes('**title**: Expected type `"string"`, received "number"'), true);
 		});
 	});
 	describe('With config.mts', () => {
@@ -234,7 +241,7 @@ describe('Content Collections', () => {
 			} catch (e) {
 				error = e.message;
 			}
-			expect(error).to.include('**title**: Expected type `"string"`, received "number"');
+			assert.equal(error.includes('**title**: Expected type `"string"`, received "number"'), true);
 		});
 	});
 
@@ -249,7 +256,7 @@ describe('Content Collections', () => {
 			} catch (e) {
 				error = e.message;
 			}
-			expect(error).to.include('**title**: Required');
+			assert.equal(error.includes('**title**: Required'), true);
 		});
 	});
 
@@ -264,7 +271,7 @@ describe('Content Collections', () => {
 			} catch (e) {
 				error = e.message;
 			}
-			expect(error).to.be.undefined;
+			assert.equal(error, undefined);
 			// TODO: try to render a page
 		});
 	});
@@ -289,7 +296,7 @@ describe('Content Collections', () => {
 			for (const slug in blogSlugToContents) {
 				const request = new Request('http://example.com/posts/' + slug);
 				const response = await app.render(request);
-				expect(response.status).to.equal(200);
+				assert.equal(response.status, 200);
 			}
 		});
 
@@ -299,7 +306,7 @@ describe('Content Collections', () => {
 				const response = await app.render(request);
 				const body = await response.text();
 				const $ = cheerio.load(body);
-				expect($('h1').text()).to.equal(blogSlugToContents[slug].title);
+				assert.equal($('h1').text(), blogSlugToContents[slug].title);
 			}
 		});
 
@@ -309,7 +316,8 @@ describe('Content Collections', () => {
 				const response = await app.render(request);
 				const body = await response.text();
 				const $ = cheerio.load(body);
-				expect($(blogSlugToContents[slug].element).text().trim()).to.equal(
+				assert.equal(
+					$(blogSlugToContents[slug].element).text().trim(),
 					blogSlugToContents[slug].content
 				);
 			}
@@ -329,13 +337,13 @@ describe('Content Collections', () => {
 		it('Includes base in links', async () => {
 			const html = await fixture.readFile('/docs/index.html');
 			const $ = cheerio.load(html);
-			expect($('link').attr('href')).to.satisfies((a) => a.startsWith('/docs'));
+			assert.equal($('link').attr('href').startsWith('/docs'), true);
 		});
 
 		it('Includes base in hoisted scripts', async () => {
 			const html = await fixture.readFile('/docs/index.html');
 			const $ = cheerio.load(html);
-			expect($('script').attr('src')).to.satisfies((a) => a.startsWith('/docs'));
+			assert.equal($('script').attr('src').startsWith('/docs'), true);
 		});
 	});
 });
diff --git a/packages/astro/test/core-image-infersize.test.js b/packages/astro/test/core-image-infersize.nodetest.js
similarity index 85%
rename from packages/astro/test/core-image-infersize.test.js
rename to packages/astro/test/core-image-infersize.nodetest.js
index 62f3422307..44c571d177 100644
--- a/packages/astro/test/core-image-infersize.test.js
+++ b/packages/astro/test/core-image-infersize.nodetest.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, after, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import { Writable } from 'node:stream';
 
@@ -48,23 +49,26 @@ describe('astro:image:infersize', () => {
 
 			it('Image component works', async () => {
 				let $img = $('img');
-				expect(
-					$img.attr('src').startsWith('/_image') && $img.attr('src').endsWith('f=webp')
-				).to.equal(true);
+				assert.equal(
+					$img.attr('src').startsWith('/_image') && $img.attr('src').endsWith('f=webp'),
+					true
+				);
 			});
 
 			it('Picture component works', async () => {
 				let $img = $('picture img');
-				expect(
-					$img.attr('src').startsWith('/_image') && $img.attr('src').endsWith('f=png')
-				).to.equal(true);
+				assert.equal(
+					$img.attr('src').startsWith('/_image') && $img.attr('src').endsWith('f=png'),
+					true
+				);
 			});
 
 			it('getImage works', async () => {
 				let $img = $('#getImage');
-				expect(
-					$img.attr('src').startsWith('/_image') && $img.attr('src').endsWith('f=webp')
-				).to.equal(true);
+				assert.equal(
+					$img.attr('src').startsWith('/_image') && $img.attr('src').endsWith('f=webp'),
+					true
+				);
 			});
 		});
 	});
diff --git a/packages/astro/test/core-image-remark-imgattr.test.js b/packages/astro/test/core-image-remark-imgattr.nodetest.js
similarity index 85%
rename from packages/astro/test/core-image-remark-imgattr.test.js
rename to packages/astro/test/core-image-remark-imgattr.nodetest.js
index 7910143297..936decfd28 100644
--- a/packages/astro/test/core-image-remark-imgattr.test.js
+++ b/packages/astro/test/core-image-remark-imgattr.nodetest.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, after, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import { Writable } from 'node:stream';
 
@@ -48,14 +49,12 @@ describe('astro:image', () => {
 
 			it('Image has eager loading meaning getImage passed props it doesnt use through it', async () => {
 				let $img = $('img');
-				expect($img.attr('loading')).to.equal('eager');
+				assert.equal($img.attr('loading'), 'eager');
 			});
 
 			it('Image src contains w=50 meaning getImage correctly used props added through the remark plugin', async () => {
 				let $img = $('img');
-				expect(new URL($img.attr('src'), 'http://example.com').searchParams.get('w')).to.equal(
-					'50'
-				);
+				assert.equal(new URL($img.attr('src'), 'http://example.com').searchParams.get('w'), '50');
 			});
 		});
 	});
diff --git a/packages/astro/test/core-image.test.js b/packages/astro/test/core-image.nodetest.js
similarity index 74%
rename from packages/astro/test/core-image.test.js
rename to packages/astro/test/core-image.nodetest.js
index 1b5618349f..561c7dc2e6 100644
--- a/packages/astro/test/core-image.test.js
+++ b/packages/astro/test/core-image.nodetest.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, after, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import { basename } from 'node:path';
 import { Writable } from 'node:stream';
@@ -56,57 +57,57 @@ describe('astro:image', () => {
 
 			it('Adds the <img> tag', () => {
 				let $img = $('#local img');
-				expect($img).to.have.a.lengthOf(1);
-				expect($img.attr('src').startsWith('/_image')).to.equal(true);
+				assert.equal($img.length, 1);
+				assert.equal($img.attr('src').startsWith('/_image'), true);
 			});
 
 			it('includes loading and decoding attributes', () => {
 				let $img = $('#local img');
-				expect(!!$img.attr('loading')).to.equal(true);
-				expect(!!$img.attr('decoding')).to.equal(true);
+				assert.equal(!!$img.attr('loading'), true);
+				assert.equal(!!$img.attr('decoding'), true);
 			});
 
 			it('has width and height - no dimensions set', () => {
 				let $img = $('#local img');
-				expect($img.attr('width')).to.equal('207');
-				expect($img.attr('height')).to.equal('243');
+				assert.equal($img.attr('width'), '207');
+				assert.equal($img.attr('height'), '243');
 			});
 
 			it('has proper width and height - only width', () => {
 				let $img = $('#local-width img');
-				expect($img.attr('width')).to.equal('350');
-				expect($img.attr('height')).to.equal('411');
+				assert.equal($img.attr('width'), '350');
+				assert.equal($img.attr('height'), '411');
 			});
 
 			it('has proper width and height - only height', () => {
 				let $img = $('#local-height img');
-				expect($img.attr('width')).to.equal('170');
-				expect($img.attr('height')).to.equal('200');
+				assert.equal($img.attr('width'), '170');
+				assert.equal($img.attr('height'), '200');
 			});
 
 			it('has proper width and height - has both width and height', () => {
 				let $img = $('#local-both img');
-				expect($img.attr('width')).to.equal('300');
-				expect($img.attr('height')).to.equal('400');
+				assert.equal($img.attr('width'), '300');
+				assert.equal($img.attr('height'), '400');
 			});
 
 			it('includes the provided alt', () => {
 				let $img = $('#local img');
-				expect($img.attr('alt')).to.equal('a penguin');
+				assert.equal($img.attr('alt'), 'a penguin');
 			});
 
 			it('middleware loads the file', async () => {
 				let $img = $('#local img');
 				let src = $img.attr('src');
 				let res = await fixture.fetch(src);
-				expect(res.status).to.equal(200);
+				assert.equal(res.status, 200);
 			});
 
 			it('returns proper content-type', async () => {
 				let $img = $('#local img');
 				let src = $img.attr('src');
 				let res = await fixture.fetch(src);
-				expect(res.headers.get('content-type')).to.equal('image/webp');
+				assert.equal(res.headers.get('content-type'), 'image/webp');
 			});
 
 			it('properly skip processing SVGs, but does not error', async () => {
@@ -115,11 +116,11 @@ describe('astro:image', () => {
 
 				$ = cheerio.load(html);
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(1);
+				assert.equal($img.length, 1);
 
 				let src = $img.attr('src');
 				res = await fixture.fetch(src);
-				expect(res.status).to.equal(200);
+				assert.equal(res.status, 200);
 			});
 
 			it("errors when an ESM imported image's src is passed to Image/getImage instead of the full import", async () => {
@@ -127,8 +128,8 @@ describe('astro:image', () => {
 				let res = await fixture.fetch('/error-image-src-passed');
 				await res.text();
 
-				expect(logs).to.have.a.lengthOf(1);
-				expect(logs[0].message).to.contain('must be an imported image or an URL');
+				assert.equal(logs.length, 1);
+				assert.equal(logs[0].message.includes('must be an imported image or an URL'), true);
 			});
 
 			it('supports images from outside the project', async () => {
@@ -137,15 +138,16 @@ describe('astro:image', () => {
 				$ = cheerio.load(html);
 
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(2);
-				expect(
+				assert.equal($img.length, 2);
+				assert.equal(
 					$img.toArray().every((img) => {
 						return (
 							img.attribs['src'].startsWith('/@fs/') ||
 							img.attribs['src'].startsWith('/_image?href=%2F%40fs%2F')
 						);
-					})
-				).to.be.true;
+					}),
+					true
+				);
 			});
 
 			it('supports inlined imports', async () => {
@@ -154,11 +156,11 @@ describe('astro:image', () => {
 				$ = cheerio.load(html);
 
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(1);
+				assert.equal($img.length, 1);
 
 				let src = $img.attr('src');
 				res = await fixture.fetch(src);
-				expect(res.status).to.equal(200);
+				assert.equal(res.status, 200);
 			});
 
 			it('supports uppercased imports', async () => {
@@ -167,13 +169,13 @@ describe('astro:image', () => {
 				$ = cheerio.load(html);
 
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(1);
+				assert.equal($img.length, 1);
 
 				let src = $img.attr('src');
 				let loading = $img.attr('loading');
 				res = await fixture.fetch(src);
-				expect(res.status).to.equal(200);
-				expect(loading).to.not.be.undefined;
+				assert.equal(res.status, 200);
+				assert.notEqual(loading, undefined);
 			});
 
 			it('supports avif', async () => {
@@ -182,12 +184,12 @@ describe('astro:image', () => {
 				$ = cheerio.load(html);
 
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(1);
+				assert.equal($img.length, 1);
 
 				let src = $img.attr('src');
 				res = await fixture.fetch(src);
-				expect(res.status).to.equal(200);
-				expect(res.headers.get('content-type')).to.equal('image/avif');
+				assert.equal(res.status, 200);
+				assert.equal(res.headers.get('content-type'), 'image/avif');
 			});
 
 			it('has a working Picture component', async () => {
@@ -197,38 +199,51 @@ describe('astro:image', () => {
 
 				// Fallback format
 				let $img = $('#picture-fallback img');
-				expect($img).to.have.a.lengthOf(1);
+				assert.equal($img.length, 1);
 
 				const imageURL = new URL($img.attr('src'), 'http://localhost');
-				expect(imageURL.searchParams.get('f')).to.equal('jpeg');
-				expect($img.attr('fallbackformat')).to.be.undefined;
+				assert.equal(imageURL.searchParams.get('f'), 'jpeg');
+				assert.equal($img.attr('fallbackformat'), undefined);
 
 				// Densities
 				$img = $('#picture-density-2-format img');
 				let $picture = $('#picture-density-2-format picture');
 				let $source = $('#picture-density-2-format source');
-				expect($img).to.have.a.lengthOf(1);
-				expect($picture).to.have.a.lengthOf(1);
-				expect($source).to.have.a.lengthOf(2);
+				assert.equal($img.length, 1);
+				assert.equal($picture.length, 1);
+				assert.equal($source.length, 2);
 
 				const srcset = parseSrcset($source.attr('srcset'));
-				expect(srcset.every((src) => src.url.startsWith('/_image'))).to.equal(true);
-				expect(srcset.map((src) => src.d)).to.deep.equal([undefined, 2]);
+				assert.equal(
+					srcset.every((src) => src.url.startsWith('/_image')),
+					true
+				);
+				assert.deepEqual(
+					srcset.map((src) => src.d),
+					[undefined, 2]
+				);
 
 				// Widths
 				$img = $('#picture-widths img');
 				$picture = $('#picture-widths picture');
 				$source = $('#picture-widths source');
-				expect($img).to.have.a.lengthOf(1);
-				expect($picture).to.have.a.lengthOf(1);
-				expect($source).to.have.a.lengthOf(1);
-				expect($source.attr('sizes')).to.equal(
+				assert.equal($img.length, 1);
+				assert.equal($picture.length, 1);
+				assert.equal($source.length, 1);
+				assert.equal(
+					$source.attr('sizes'),
 					'(max-width: 448px) 400px, (max-width: 810px) 750px, 1050px'
 				);
 
 				const srcset2 = parseSrcset($source.attr('srcset'));
-				expect(srcset2.every((src) => src.url.startsWith('/_image'))).to.equal(true);
-				expect(srcset2.map((src) => src.w)).to.deep.equal([207]);
+				assert.equal(
+					srcset2.every((src) => src.url.startsWith('/_image')),
+					true
+				);
+				assert.deepEqual(
+					srcset2.map((src) => src.w),
+					[207]
+				);
 			});
 
 			it('properly deduplicate srcset images', async () => {
@@ -237,52 +252,58 @@ describe('astro:image', () => {
 				$ = cheerio.load(html);
 
 				let localImage = $('#local-3-images img');
-				expect(
+				assert.equal(
 					new Set([
 						...parseSrcset(localImage.attr('srcset')).map((src) => src.url),
 						localImage.attr('src'),
-					]).size
-				).to.equal(3);
+					]).size,
+					3
+				);
 
 				let remoteImage = $('#remote-3-images img');
-				expect(
+				assert.equal(
 					new Set([
 						...parseSrcset(remoteImage.attr('srcset')).map((src) => src.url),
 						remoteImage.attr('src'),
-					]).size
-				).to.equal(3);
+					]).size,
+					3
+				);
 
 				let local1x = $('#local-1x img');
-				expect(
+				assert.equal(
 					new Set([
 						...parseSrcset(local1x.attr('srcset')).map((src) => src.url),
 						local1x.attr('src'),
-					]).size
-				).to.equal(1);
+					]).size,
+					1
+				);
 
 				let remote1x = $('#remote-1x img');
-				expect(
+				assert.equal(
 					new Set([
 						...parseSrcset(remote1x.attr('srcset')).map((src) => src.url),
 						remote1x.attr('src'),
-					]).size
-				).to.equal(1);
+					]).size,
+					1
+				);
 
 				let local2Widths = $('#local-2-widths img');
-				expect(
+				assert.equal(
 					new Set([
 						...parseSrcset(local2Widths.attr('srcset')).map((src) => src.url),
 						local2Widths.attr('src'),
-					]).size
-				).to.equal(2);
+					]).size,
+					2
+				);
 
 				let remote2Widths = $('#remote-2-widths img');
-				expect(
+				assert.equal(
 					new Set([
 						...parseSrcset(remote2Widths.attr('srcset')).map((src) => src.url),
 						remote2Widths.attr('src'),
-					]).size
-				).to.equal(2);
+					]).size,
+					2
+				);
 			});
 		});
 
@@ -299,17 +320,17 @@ describe('astro:image', () => {
 
 			it('support ?url imports', () => {
 				let $url = $('#url');
-				expect($url.text()).to.equal('string');
+				assert.equal($url.text(), 'string');
 			});
 
 			it('support ?raw imports', () => {
 				let $raw = $('#raw');
-				expect($raw.text()).to.equal('string');
+				assert.equal($raw.text(), 'string');
 			});
 
 			it('support glob import as raw', () => {
 				let $raw = $('#glob-import');
-				expect($raw.text()).to.equal('string');
+				assert.equal($raw.text(), 'string');
 			});
 		});
 
@@ -326,42 +347,43 @@ describe('astro:image', () => {
 					let $img = $('#remote img');
 
 					let src = $img.attr('src');
-					expect(src.startsWith('/_image?')).to.be.true;
+					assert.ok(src.startsWith('/_image?'));
 					const imageRequest = await fixture.fetch(src);
-					expect(imageRequest.status).to.equal(200);
+					assert.equal(imageRequest.status, 200);
 				});
 
 				it('includes the provided alt', async () => {
 					let $img = $('#remote img');
-					expect($img.attr('alt')).to.equal('fred');
+					assert.equal($img.attr('alt'), 'fred');
 				});
 
 				it('includes loading and decoding attributes', () => {
 					let $img = $('#remote img');
-					expect(!!$img.attr('loading')).to.equal(true);
-					expect(!!$img.attr('decoding')).to.equal(true);
+					assert.equal(!!$img.attr('loading'), true);
+					assert.equal(!!$img.attr('decoding'), true);
 				});
 
 				it('includes width and height attributes', () => {
 					let $img = $('#remote img');
-					expect(!!$img.attr('width')).to.equal(true);
-					expect(!!$img.attr('height')).to.equal(true);
+					assert.equal(!!$img.attr('width'), true);
+					assert.equal(!!$img.attr('height'), true);
 				});
 
 				it('support data: URI', () => {
 					let $img = $('#data-uri img');
-					expect($img.attr('src')).to.equal(
+					assert.equal(
+						$img.attr('src'),
 						'data:image/png;base64,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'
 					);
-					expect(!!$img.attr('width')).to.equal(true);
-					expect(!!$img.attr('height')).to.equal(true);
+					assert.equal(!!$img.attr('width'), true);
+					assert.equal(!!$img.attr('height'), true);
 				});
 
 				it('support images from public', () => {
 					let $img = $('#public img');
-					expect($img.attr('src')).to.equal('/penguin3.jpg');
-					expect(!!$img.attr('width')).to.equal(true);
-					expect(!!$img.attr('height')).to.equal(true);
+					assert.equal($img.attr('src'), '/penguin3.jpg');
+					assert.equal(!!$img.attr('width'), true);
+					assert.equal(!!$img.attr('height'), true);
 				});
 			});
 
@@ -370,8 +392,8 @@ describe('astro:image', () => {
 				let res = await fixture.fetch('/remote-error-no-dimensions');
 				await res.text();
 
-				expect(logs).to.have.a.lengthOf(1);
-				expect(logs[0].message).to.contain('Missing width and height attributes');
+				assert.equal(logs.length, 1);
+				assert.equal(logs[0].message.includes('Missing width and height attributes'), true);
 			});
 
 			it('error if no height', async () => {
@@ -379,8 +401,8 @@ describe('astro:image', () => {
 				let res = await fixture.fetch('/remote-error-no-height');
 				await res.text();
 
-				expect(logs).to.have.a.lengthOf(1);
-				expect(logs[0].message).to.contain('Missing height attribute');
+				assert.equal(logs.length, 1);
+				assert.equal(logs[0].message.includes('Missing height attribute'), true);
 			});
 
 			it('supports aliases', async () => {
@@ -389,8 +411,8 @@ describe('astro:image', () => {
 				let $ = cheerio.load(html);
 
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(1);
-				expect($img.attr('src').includes('penguin1.jpg')).to.equal(true);
+				assert.equal($img.length, 1);
+				assert.equal($img.attr('src').includes('penguin1.jpg'), true);
 			});
 		});
 
@@ -404,18 +426,19 @@ describe('astro:image', () => {
 
 			it('Adds the <img> tag', () => {
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(2);
+				assert.equal($img.length, 2);
 
 				// Verbose test for the full URL to make sure the image went through the full pipeline
-				expect(
-					$img.attr('src').startsWith('/_image') && $img.attr('src').endsWith('f=webp')
-				).to.equal(true);
+				assert.equal(
+					$img.attr('src').startsWith('/_image') && $img.attr('src').endsWith('f=webp'),
+					true
+				);
 			});
 
 			it('has width and height attributes', () => {
 				let $img = $('img');
-				expect(!!$img.attr('width')).to.equal(true);
-				expect(!!$img.attr('height')).to.equal(true);
+				assert.equal(!!$img.attr('width'), true);
+				assert.equal(!!$img.attr('height'), true);
 			});
 
 			it('Supports aliased paths', async () => {
@@ -424,7 +447,7 @@ describe('astro:image', () => {
 				$ = cheerio.load(html);
 
 				let $img = $('img');
-				expect($img.attr('src').startsWith('/_image')).to.equal(true);
+				assert.equal($img.attr('src').startsWith('/_image'), true);
 			});
 
 			it('Supports special characters in file name', async () => {
@@ -433,7 +456,7 @@ describe('astro:image', () => {
 				$ = cheerio.load(html);
 
 				let $img = $('img');
-				expect($img.attr('src').startsWith('/_image')).to.equal(true);
+				assert.equal($img.attr('src').startsWith('/_image'), true);
 			});
 
 			it('properly handles remote images', async () => {
@@ -442,10 +465,10 @@ describe('astro:image', () => {
 				$ = cheerio.load(html);
 
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(2);
+				assert.equal($img.length, 2);
 				const remoteUrls = ['https://example.com/image.png', '/image.png'];
 				$img.each((index, element) => {
-					expect(element.attribs['src']).to.equal(remoteUrls[index]);
+					assert.equal(element.attribs['src'], remoteUrls[index]);
 				});
 			});
 		});
@@ -460,13 +483,13 @@ describe('astro:image', () => {
 
 			it('Adds the <img> tag', () => {
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(1);
-				expect($img.attr('src').startsWith('/_image')).to.equal(true);
+				assert.equal($img.length, 1);
+				assert.equal($img.attr('src').startsWith('/_image'), true);
 			});
 
 			it('includes the provided alt', () => {
 				let $img = $('img');
-				expect($img.attr('alt')).to.equal('a penguin');
+				assert.equal($img.attr('alt'), 'a penguin');
 			});
 		});
 
@@ -480,52 +503,55 @@ describe('astro:image', () => {
 
 			it('Adds the <img> tags', () => {
 				let $img = $('img');
-				expect($img).to.have.a.lengthOf(8);
+				assert.equal($img.length, 8);
 			});
 
 			it('image in cc folder is processed', () => {
 				let $imgs = $('img');
 				let $blogfolderimg = $($imgs[7]);
-				expect($blogfolderimg.attr('src')).to.include('blogfolder.jpg');
-				expect($blogfolderimg.attr('src').endsWith('f=webp')).to.equal(true);
+				assert.equal($blogfolderimg.attr('src').includes('blogfolder.jpg'), true);
+				assert.equal($blogfolderimg.attr('src').endsWith('f=webp'), true);
 			});
 
 			it('has proper source for directly used image', () => {
 				let $img = $('#direct-image img');
-				expect($img.attr('src').startsWith('/')).to.equal(true);
+				assert.equal($img.attr('src').startsWith('/'), true);
 			});
 
 			it('has proper source for refined image', () => {
 				let $img = $('#refined-image img');
-				expect($img.attr('src').startsWith('/')).to.equal(true);
+				assert.equal($img.attr('src').startsWith('/'), true);
 			});
 
 			it('has proper sources for array of images', () => {
 				let $img = $('#array-of-images img');
 				const imgsSrcs = [];
 				$img.each((i, img) => imgsSrcs.push(img.attribs['src']));
-				expect($img).to.have.a.lengthOf(2);
-				expect(imgsSrcs.every((img) => img.startsWith('/'))).to.be.true;
+				assert.equal($img.length, 2);
+				assert.equal(
+					imgsSrcs.every((img) => img.startsWith('/')),
+					true
+				);
 			});
 
 			it('has proper attributes for optimized image through getImage', () => {
 				let $img = $('#optimized-image-get-image img');
-				expect($img.attr('src').startsWith('/_image')).to.equal(true);
-				expect($img.attr('width')).to.equal('207');
-				expect($img.attr('height')).to.equal('243');
+				assert.equal($img.attr('src').startsWith('/_image'), true);
+				assert.equal($img.attr('width'), '207');
+				assert.equal($img.attr('height'), '243');
 			});
 
 			it('has proper attributes for optimized image through Image component', () => {
 				let $img = $('#optimized-image-component img');
-				expect($img.attr('src').startsWith('/_image')).to.equal(true);
-				expect($img.attr('width')).to.equal('207');
-				expect($img.attr('height')).to.equal('243');
-				expect($img.attr('alt')).to.equal('A penguin!');
+				assert.equal($img.attr('src').startsWith('/_image'), true);
+				assert.equal($img.attr('width'), '207');
+				assert.equal($img.attr('height'), '243');
+				assert.equal($img.attr('alt'), 'A penguin!');
 			});
 
 			it('properly handles nested images', () => {
 				let $img = $('#nested-image img');
-				expect($img.attr('src').startsWith('/')).to.equal(true);
+				assert.equal($img.attr('src').startsWith('/'), true);
 			});
 		});
 
@@ -539,11 +565,11 @@ describe('astro:image', () => {
 			});
 
 			it('does not have a file url', async () => {
-				expect($('img').attr('src').startsWith('file://')).to.equal(false);
+				assert.equal($('img').attr('src').startsWith('file://'), false);
 			});
 
 			it('includes /src in the path', async () => {
-				expect($('img').attr('src').includes('/src')).to.equal(true);
+				assert.equal($('img').attr('src').includes('/src'), true);
 			});
 		});
 
@@ -553,7 +579,7 @@ describe('astro:image', () => {
 				const html = await response.text();
 
 				const $ = cheerio.load(html);
-				expect($('#local img').attr('data-service')).to.equal('my-custom-service');
+				assert.equal($('#local img').attr('data-service'), 'my-custom-service');
 			});
 
 			it('custom service works in Markdown', async () => {
@@ -561,7 +587,7 @@ describe('astro:image', () => {
 				const html = await response.text();
 
 				const $ = cheerio.load(html);
-				expect($('img').attr('data-service')).to.equal('my-custom-service');
+				assert.equal($('img').attr('data-service'), 'my-custom-service');
 			});
 
 			it('gets service config', async () => {
@@ -569,7 +595,7 @@ describe('astro:image', () => {
 				const html = await response.text();
 
 				const $ = cheerio.load(html);
-				expect($('#local img').attr('data-service-config')).to.equal('bar');
+				assert.equal($('#local img').attr('data-service-config'), 'bar');
 			});
 		});
 
@@ -603,8 +629,9 @@ describe('astro:image', () => {
 				const src = $('#local img').attr('src');
 
 				let res = await customEndpointFixture.fetch(src);
-				expect(res.status).to.equal(200);
-				expect(await res.text()).to.equal(
+				assert.equal(res.status, 200);
+				assert.equal(
+					await res.text(),
 					"You fool! I'm not a image endpoint at all, I just return this!"
 				);
 			});
@@ -652,8 +679,8 @@ describe('astro:image', () => {
 			let res = await fixture.fetch('/get-image-empty');
 			await res.text();
 
-			expect(logs).to.have.a.lengthOf(1);
-			expect(logs[0].message).to.contain('Expected getImage() parameter');
+			assert.equal(logs.length, 1);
+			assert.equal(logs[0].message.includes('Expected getImage() parameter'), true);
 		});
 
 		it('properly error when src is undefined', async () => {
@@ -661,8 +688,8 @@ describe('astro:image', () => {
 			let res = await fixture.fetch('/get-image-undefined');
 			await res.text();
 
-			expect(logs).to.have.a.lengthOf(1);
-			expect(logs[0].message).to.contain('Expected `src` property');
+			assert.equal(logs.length, 1);
+			assert.equal(logs[0].message.includes('Expected `src` property'), true);
 		});
 
 		it('properly error image in Markdown frontmatter is not found', async () => {
@@ -670,16 +697,16 @@ describe('astro:image', () => {
 			let res = await fixture.fetch('/blog/one');
 			await res.text();
 
-			expect(logs).to.have.a.lengthOf(1);
-			expect(logs[0].message).to.contain('does not exist. Is the path correct?');
+			assert.equal(logs.length, 1);
+			assert.equal(logs[0].message.includes('does not exist. Is the path correct?'), true);
 		});
 
 		it('properly error image in Markdown content is not found', async () => {
 			logs.length = 0;
 			let res = await fixture.fetch('/post');
 			await res.text();
-			expect(logs).to.have.a.lengthOf(1);
-			expect(logs[0].message).to.contain('Could not find requested image');
+			assert.equal(logs.length, 1);
+			assert.equal(logs[0].message.includes('Could not find requested image'), true);
 		});
 	});
 
@@ -699,40 +726,40 @@ describe('astro:image', () => {
 			const html = await fixture.readFile('/index.html');
 			const $ = cheerio.load(html);
 			const src = $('#local img').attr('src');
-			expect(src.length).to.be.greaterThan(0);
-			expect(src.startsWith('/blog')).to.be.true;
+			assert.equal(src.length > 0, true);
+			assert.equal(src.startsWith('/blog'), true);
 		});
 
 		it('has base path prefix when using getImage', async () => {
 			const html = await fixture.readFile('/get-image/index.html');
 			const $ = cheerio.load(html);
 			const src = $('img').attr('src');
-			expect(src.length).to.be.greaterThan(0);
-			expect(src.startsWith('/blog')).to.be.true;
+			assert.equal(src.length > 0, true);
+			assert.equal(src.startsWith('/blog'), true);
 		});
 
 		it('has base path prefix when using image directly', async () => {
 			const html = await fixture.readFile('/direct/index.html');
 			const $ = cheerio.load(html);
 			const src = $('img').attr('src');
-			expect(src.length).to.be.greaterThan(0);
-			expect(src.startsWith('/blog')).to.be.true;
+			assert.equal(src.length > 0, true);
+			assert.equal(src.startsWith('/blog'), true);
 		});
 
 		it('has base path prefix in Markdown', async () => {
 			const html = await fixture.readFile('/post/index.html');
 			const $ = cheerio.load(html);
 			const src = $('img').attr('src');
-			expect(src.length).to.be.greaterThan(0);
-			expect(src.startsWith('/blog')).to.be.true;
+			assert.equal(src.length > 0, true);
+			assert.equal(src.startsWith('/blog'), true);
 		});
 
 		it('has base path prefix in Content Collection frontmatter', async () => {
 			const html = await fixture.readFile('/blog/one/index.html');
 			const $ = cheerio.load(html);
 			const src = $('img').attr('src');
-			expect(src.length).to.be.greaterThan(0);
-			expect(src.startsWith('/blog')).to.be.true;
+			assert.equal(src.length > 0, true);
+			assert.equal(src.startsWith('/blog'), true);
 		});
 
 		it('has base path prefix in SSR', async () => {
@@ -749,11 +776,11 @@ describe('astro:image', () => {
 			const app = await fixtureWithBase.loadTestAdapterApp();
 			const request = new Request('http://example.com/blog/');
 			const response = await app.render(request);
-			expect(response.status).to.equal(200);
+			assert.equal(response.status, 200);
 			const html = await response.text();
 			const $ = cheerio.load(html);
 			const src = $('#local img').attr('src');
-			expect(src.startsWith('/blog')).to.be.true;
+			assert.equal(src.startsWith('/blog'), true);
 		});
 	});
 
@@ -776,25 +803,25 @@ describe('astro:image', () => {
 			const html = await fixture.readFile('/index.html');
 			const $ = cheerio.load(html);
 			const src = $('#local img').attr('src');
-			expect(src.length).to.be.greaterThan(0);
+			assert.equal(src.length > 0, true);
 			const data = await fixture.readFile(src, null);
-			expect(data).to.be.an.instanceOf(Buffer);
+			assert.equal(data instanceof Buffer, true);
 		});
 
 		it('writes out allowed remote images', async () => {
 			const html = await fixture.readFile('/remote/index.html');
 			const $ = cheerio.load(html);
 			const src = $('#remote img').attr('src');
-			expect(src.length).to.be.greaterThan(0);
+			assert.equal(src.length > 0, true);
 			const data = await fixture.readFile(src, null);
-			expect(data).to.be.an.instanceOf(Buffer);
+			assert.equal(data instanceof Buffer, true);
 		});
 
 		it('writes out images to dist folder with proper extension if no format was passed', async () => {
 			const html = await fixture.readFile('/index.html');
 			const $ = cheerio.load(html);
 			const src = $('#local img').attr('src');
-			expect(src.endsWith('.webp')).to.be.true;
+			assert.equal(src.endsWith('.webp'), true);
 		});
 
 		it('getImage() usage also written', async () => {
@@ -803,13 +830,13 @@ describe('astro:image', () => {
 			let $img = $('img');
 
 			// <img> tag
-			expect($img).to.have.a.lengthOf(1);
-			expect($img.attr('alt')).to.equal('a penguin');
+			assert.equal($img.length, 1);
+			assert.equal($img.attr('alt'), 'a penguin');
 
 			// image itself
 			const src = $img.attr('src');
 			const data = await fixture.readFile(src, null);
-			expect(data).to.be.an.instanceOf(Buffer);
+			assert.equal(data instanceof Buffer, true);
 		});
 
 		it('Picture component images are written', async () => {
@@ -818,8 +845,8 @@ describe('astro:image', () => {
 			let $img = $('img');
 			let $source = $('source');
 
-			expect($img).to.have.a.lengthOf(1);
-			expect($source).to.have.a.lengthOf(2);
+			assert.equal($img.length, 1);
+			assert.equal($source.length, 2);
 
 			const srcset = parseSrcset($source.attr('srcset'));
 			let hasExistingSrc = await Promise.all(
@@ -829,7 +856,10 @@ describe('astro:image', () => {
 				})
 			);
 
-			expect(hasExistingSrc.every((src) => src === true)).to.deep.equal(true);
+			assert.deepEqual(
+				hasExistingSrc.every((src) => src === true),
+				true
+			);
 		});
 
 		it('markdown images are written', async () => {
@@ -838,13 +868,13 @@ describe('astro:image', () => {
 			let $img = $('img');
 
 			// <img> tag
-			expect($img).to.have.a.lengthOf(1);
-			expect($img.attr('alt')).to.equal('My article cover');
+			assert.equal($img.length, 1);
+			assert.equal($img.attr('alt'), 'My article cover');
 
 			// image itself
 			const src = $img.attr('src');
 			const data = await fixture.readFile(src, null);
-			expect(data).to.be.an.instanceOf(Buffer);
+			assert.equal(data instanceof Buffer, true);
 		});
 
 		it('aliased images are written', async () => {
@@ -854,13 +884,13 @@ describe('astro:image', () => {
 			let $img = $('img');
 
 			// <img> tag
-			expect($img).to.have.a.lengthOf(1);
-			expect($img.attr('alt')).to.equal('A penguin!');
+			assert.equal($img.length, 1);
+			assert.equal($img.attr('alt'), 'A penguin!');
 
 			// image itself
 			const src = $img.attr('src');
 			const data = await fixture.readFile(src, null);
-			expect(data).to.be.an.instanceOf(Buffer);
+			assert.equal(data instanceof Buffer, true);
 		});
 
 		it('aliased images in Markdown are written', async () => {
@@ -870,13 +900,13 @@ describe('astro:image', () => {
 			let $img = $('img');
 
 			// <img> tag
-			expect($img).to.have.a.lengthOf(1);
-			expect($img.attr('alt')).to.equal('A penguin');
+			assert.equal($img.length, 1);
+			assert.equal($img.attr('alt'), 'A penguin');
 
 			// image itself
 			const src = $img.attr('src');
 			const data = await fixture.readFile(src, null);
-			expect(data).to.be.an.instanceOf(Buffer);
+			assert.equal(data instanceof Buffer, true);
 		});
 
 		it('output files for content collections images', async () => {
@@ -884,33 +914,33 @@ describe('astro:image', () => {
 
 			const $ = cheerio.load(html);
 			let $img = $('img');
-			expect($img).to.have.a.lengthOf(2);
+			assert.equal($img.length, 2);
 
 			const srcdirect = $('#direct-image img').attr('src');
 			const datadirect = await fixture.readFile(srcdirect, null);
-			expect(datadirect).to.be.an.instanceOf(Buffer);
+			assert.equal(datadirect instanceof Buffer, true);
 
 			const srcnested = $('#nested-image img').attr('src');
 			const datanested = await fixture.readFile(srcnested, null);
-			expect(datanested).to.be.an.instanceOf(Buffer);
+			assert.equal(datanested instanceof Buffer, true);
 		});
 
 		it('quality attribute produces a different file', async () => {
 			const html = await fixture.readFile('/quality/index.html');
 			const $ = cheerio.load(html);
-			expect($('#no-quality img').attr('src')).to.not.equal($('#quality-low img').attr('src'));
+			assert.notEqual($('#no-quality img').attr('src'), $('#quality-low img').attr('src'));
 		});
 
 		it('quality can be a number between 0-100', async () => {
 			const html = await fixture.readFile('/quality/index.html');
 			const $ = cheerio.load(html);
-			expect($('#no-quality img').attr('src')).to.not.equal($('#quality-num img').attr('src'));
+			assert.notEqual($('#no-quality img').attr('src'), $('#quality-num img').attr('src'));
 		});
 
 		it('format attribute produces a different file', async () => {
 			const html = await fixture.readFile('/format/index.html');
 			const $ = cheerio.load(html);
-			expect($('#no-format img').attr('src')).to.not.equal($('#format-avif img').attr('src'));
+			assert.notEqual($('#no-format img').attr('src'), $('#format-avif img').attr('src'));
 		});
 
 		it('has cache entries', async () => {
@@ -924,7 +954,7 @@ describe('astro:image', () => {
 				.map((path) => basename(path).replace('.webp.json', '.webp'))
 				.sort();
 
-			expect(generatedImages).to.deep.equal(cachedImages);
+			assert.deepEqual(generatedImages, cachedImages);
 		});
 
 		it('uses cache entries', async () => {
@@ -946,7 +976,7 @@ describe('astro:image', () => {
 				logLine.message.includes('(reused cache entry)')
 			);
 
-			expect(isReusingCache).to.be.true;
+			assert.equal(isReusingCache, true);
 		});
 
 		it('client images are written to build', async () => {
@@ -958,7 +988,7 @@ describe('astro:image', () => {
 			const regex = /src:"([^"]*)/;
 			const imageSrc = regex.exec($script.html())[1];
 			const data = await fixture.readFile(imageSrc, null);
-			expect(data).to.be.an.instanceOf(Buffer);
+			assert.equal(data instanceof Buffer, true);
 		});
 
 		it('client images srcset parsed correctly', async () => {
@@ -969,7 +999,7 @@ describe('astro:image', () => {
 			// Find image
 			const regex = /^(.+?) \d+[wx]$/m;
 			const imageSrcset = regex.exec(srcset)[1];
-			expect(imageSrcset).to.not.contain(' ');
+			assert.notEqual(imageSrcset.includes(' '), true);
 		});
 
 		it('supports images with encoded characters in url', async () => {
@@ -978,7 +1008,7 @@ describe('astro:image', () => {
 			const img = $('#encoded-chars img');
 			const src = img.attr('src');
 			const data = await fixture.readFile(src);
-			expect(data).to.not.be.undefined;
+			assert.notEqual(data, undefined);
 		});
 
 		describe('custom service in build', () => {
@@ -992,15 +1022,20 @@ describe('astro:image', () => {
 					.map((_, el) => $(el).attr('src'))
 					.get();
 
-				expect(allTheSamePath.every((path) => path === allTheSamePath[0])).to.equal(true);
+				assert.equal(
+					allTheSamePath.every((path) => path === allTheSamePath[0]),
+					true
+				);
 
 				const useCustomHashProperty = $('#use-data img')
 					.map((_, el) => $(el).attr('src'))
 					.get();
-				expect(useCustomHashProperty.every((path) => path === useCustomHashProperty[0])).to.equal(
+				assert.equal(
+					useCustomHashProperty.every((path) => path === useCustomHashProperty[0]),
 					false
 				);
-				expect(useCustomHashProperty[1]).to.not.equal(allTheSamePath[0]);
+
+				assert.notEqual(useCustomHashProperty[1], useCustomHashProperty[0]);
 			});
 		});
 	});
@@ -1026,7 +1061,7 @@ describe('astro:image', () => {
 		it('does not interfere with query params', async () => {
 			let res = await fixture.fetch('/api?src=image.png');
 			const html = await res.text();
-			expect(html).to.equal('An image: "image.png"');
+			assert.equal(html, 'An image: "image.png"');
 		});
 	});
 
@@ -1048,13 +1083,13 @@ describe('astro:image', () => {
 			const app = await fixture.loadTestAdapterApp();
 			let request = new Request('http://example.com/');
 			let response = await app.render(request);
-			expect(response.status).to.equal(200);
+			assert.equal(response.status, 200);
 			const html = await response.text();
 			const $ = cheerio.load(html);
 			const src = $('#local img').attr('src');
 			request = new Request('http://example.com' + src);
 			response = await app.render(request);
-			expect(response.status).to.equal(200);
+			assert.equal(response.status, 200);
 		});
 
 		it('prerendered routes images are built', async () => {
@@ -1062,7 +1097,7 @@ describe('astro:image', () => {
 			const $ = cheerio.load(html);
 			const src = $('img').attr('src');
 			const imgData = await fixture.readFile('/client' + src, null);
-			expect(imgData).to.be.an.instanceOf(Buffer);
+			assert.equal(imgData instanceof Buffer, true);
 		});
 	});
 });
diff --git a/packages/astro/test/custom-assets-name.test.js b/packages/astro/test/custom-assets-name.nodetest.js
similarity index 81%
rename from packages/astro/test/custom-assets-name.test.js
rename to packages/astro/test/custom-assets-name.nodetest.js
index c441169210..7f101cbf1f 100644
--- a/packages/astro/test/custom-assets-name.test.js
+++ b/packages/astro/test/custom-assets-name.nodetest.js
@@ -1,4 +1,5 @@
-import { expect } from 'chai';
+import assert from 'node:assert/strict';
+import { describe, before, it } from 'node:test';
 import { loadFixture } from './test-utils.js';
 
 describe('custom the assets name function', () => {
@@ -16,6 +17,6 @@ describe('custom the assets name function', () => {
 	it('It cant find this file cause the node throws an error if the users custom a path that includes the folder path', async () => {
 		const csslength = await fixture.readFile('client/assets/css/a.css');
 		/** @type {Set<string>} */
-		expect(!!csslength).to.equal(true);
+		assert.equal(!!csslength, true);
 	});
 });