Add a test to ensure that types.d.ts is valid (#11277)

packages/astro/test/astro-sync.test.js

@@ -1,6 +1,7 @@
 import assert from 'node:assert/strict';
 import * as fs from 'node:fs';
 import { before, describe, it } from 'node:test';
+import ts from 'typescript';
 import { loadFixture } from './test-utils.js';
 
 const createFixture = () => {
@@ -62,6 +63,20 @@ const createFixture = () => {
 			const expectedPath = new URL(path, astroFixture.config.root).href;
 			assert.equal(writtenFiles[expectedPath].includes(content), true, error);
 		},
+		thenFileShouldBeValidTypescript(path) {
+			const expectedPath = new URL(path, astroFixture.config.root).href;
+			try {
+				const content = writtenFiles[expectedPath];
+				const result = ts.transpileModule(content, {
+					compilerOptions: {
+						module: ts.ModuleKind.ESNext,
+					},
+				});
+				assert.equal(result.outputText, '', `${path} should be valid TypeScript. Output: ${result.outputText}`);
+			} catch (error) {
+				assert.fail(`${path} is not valid TypeScript. Error: ${error.message}`);
+			}
+		},
 	};
 };
 
@@ -87,6 +102,7 @@ describe('astro sync', () => {
 				`declare module 'astro:content' {`,
 				'Types file does not include `astro:content` module declaration'
 			);
+			fixture.thenFileShouldBeValidTypescript('.astro/types.d.ts');
 		});
 
 		it('Writes types for empty collections', async () => {

packages/astro/test/fixtures/content-collections/src/content/config.ts

@@ -1,5 +1,12 @@
 import { defineCollection, z } from 'astro:content';
 
+const withData = defineCollection({
+	type: 'data',
+	schema: z.object({
+		title: z.string(),
+	}),
+});
+
 const withCustomSlugs = defineCollection({
 	// Ensure schema passes even when `slug` is present
 	schema: z.object({}).strict(),
@@ -46,6 +53,7 @@ const withSymlinkedContent = defineCollection({
 });
 
 export const collections = {
+	'with-data': withData,
 	'with-custom-slugs': withCustomSlugs,
 	'with-schema-config': withSchemaConfig,
 	'with-union-schema': withUnionSchema,

packages/astro/test/fixtures/content-collections/src/content/with-data/one.json

@@ -0,0 +1,3 @@
+{
+	"title": "One"
+}

packages/astro/test/fixtures/content-collections/src/content/with-data/three.json

@@ -0,0 +1,3 @@
+{
+	"title": "Three"
+}

packages/astro/test/fixtures/content-collections/src/content/with-data/two.json

@@ -0,0 +1,3 @@
+{
+	"title": "Two"
+}