Copied DB for faster SQLite tests

refs https://github.com/TryGhost/Toolbox/issues/136

- we nuke and reinitialize the DB many times between tests
- this forms a good portion of the time taken and we shouldn't be spending
  so much time on just resetting the DB back to a known state
- this commit switches out the knex-migrator reset + init calls for SQLite to
  a function which keeps a clean copy of the DB and copies the file back
  when we "reset"
- for MySQL, existing functionality is kept
- this massively speeds up tests because it saves ~700ms+ for every reset
- whilst this change seems to work, it's just the start so there's a
  lot more refactoring needed. this change is currently gated to CI until
  it's deemed safe/sane enough to run on local machines without blowing
  up

test/utils/db-utils.js

@@ -1,6 +1,7 @@
 const debug = require('@tryghost/debug')('test:dbUtils');
 
 // Utility Packages
+const fs = require('fs-extra');
 const Promise = require('bluebird');
 const KnexMigrator = require('knex-migrator');
 const knexMigrator = new KnexMigrator();
@@ -14,6 +15,34 @@ const schemaTables = Object.keys(schema);
 // Other Test Utilities
 const urlServiceUtils = require('./url-service-utils');
 
+const dbHash = Date.now();
+
+module.exports.reset = async () => {
+    // Only run this copy in CI until it gets fleshed out
+    if (process.env.CI && config.get('database:client') === 'sqlite3') {
+        const filename = config.get('database:connection:filename');
+        const filenameOrig = `${filename}.${dbHash}-orig`;
+
+        const dbExists = await fs.pathExists(filenameOrig);
+
+        if (dbExists) {
+            await fs.copyFile(filenameOrig, filename);
+        } else {
+            await knexMigrator.reset({force: true});
+
+            // Do a full database initialisation
+            await knexMigrator.init();
+
+            await fs.copyFile(filename, filenameOrig);
+        }
+    } else {
+        await knexMigrator.reset({force: true});
+
+        // Do a full database initialisation
+        await knexMigrator.init();
+    }
+};
+
 module.exports.initData = async () => {
     await knexMigrator.init();
     await urlServiceUtils.reset();

test/utils/e2e-utils.js

@@ -101,11 +101,12 @@ const prepareContentFolder = (options) => {
 // - reload affected services
 const restartModeGhostStart = async ({frontend}) => {
     debug('Reload Mode');
-    // Teardown truncates all tables and also calls urlServiceUtils.reset();
-    await dbUtils.teardown();
 
-    // The tables have been truncated, this runs the fixture init task (init file 2) to re-add our default fixtures
-    await knexMigrator.init({only: 2});
+    // TODO: figure out why we need this if we reset again later?
+    urlServiceUtils.reset();
+
+    await dbUtils.reset();
+
     debug('init done');
 
     // Reset the settings cache
@@ -154,17 +155,13 @@ const freshModeGhostStart = async (options) => {
         debug('Fresh Start Mode');
     }
 
-    // Reset the DB
-    await knexMigrator.reset({force: true});
-
     // Stop the server (forceStart Mode)
     await stopGhost();
 
     // Reset the settings cache and disable listeners so they don't get triggered further
     settingsService.shutdown();
 
-    // Do a full database initialization
-    await knexMigrator.init();
+    await dbUtils.reset();
 
     await settingsService.init();