Update karma-webpack to work with webpack 5

Only the 5.0.0-alpha version is compatible with webpack 5, and it does not support the alternative usage we’ve been using anymore.

Reverts #2887 because of that.

.eslintrc

@@ -356,9 +356,7 @@
         ".storybook/*.js",
         "tests/js/*.js",
         "tests/e2e/*.js",
-        "tests/e2e/config/*.js",
-        "assets/src/dashboard/karma-tests.cjs",
-        "assets/src/edit-story/karma-tests.cjs"
+        "tests/e2e/config/*.js"
       ],
       "extends": [
         "plugin:node/recommended",

karma-dashboard.config.cjs

@@ -57,11 +57,11 @@ module.exports = function (config) {
 
     // Frameworks to use.
     // Available frameworks: https://npmjs.org/browse/keyword/karma-adapter
-    frameworks: ['jasmine', 'karma-puppeteer-client'],
+    frameworks: ['jasmine', 'karma-puppeteer-client', 'webpack'],
 
     // list of files / patterns to load in the browser
     files: [
-      { pattern: 'assets/src/dashboard/karma-tests.cjs', watched: false },
+      { pattern: 'assets/src/dashboard/**/karma/**/*.js', watched: false },
       { pattern: 'karma/fixture/init.js', watched: false },
       {
         pattern: '__static__/**/*',
@@ -79,7 +79,7 @@ module.exports = function (config) {
     // preprocess matching files before serving them to the browser
     // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
     preprocessors: {
-      'assets/src/dashboard/karma-tests.cjs': ['webpack', 'sourcemap'],
+      'assets/src/dashboard/**/karma/**/*.js': ['webpack', 'sourcemap'],
     },
 
     proxies: {

karma-edit-story.config.cjs

@@ -57,11 +57,11 @@ module.exports = function (config) {
 
     // Frameworks to use.
     // Available frameworks: https://npmjs.org/browse/keyword/karma-adapter
-    frameworks: ['jasmine', 'karma-puppeteer-client'],
+    frameworks: ['jasmine', 'karma-puppeteer-client', 'webpack'],
 
     // list of files / patterns to load in the browser
     files: [
-      { pattern: 'assets/src/edit-story/karma-tests.cjs', watched: false },
+      { pattern: 'assets/src/edit-story/**/karma/**/*.js', watched: false },
       { pattern: 'karma/fixture/init.js', watched: false },
       {
         pattern: '__static__/**/*',
@@ -79,7 +79,7 @@ module.exports = function (config) {
     // preprocess matching files before serving them to the browser
     // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
     preprocessors: {
-      'assets/src/edit-story/karma-tests.cjs': ['webpack', 'sourcemap'],
+      'assets/src/edit-story/**/karma/**/*.js': ['webpack', 'sourcemap'],
     },
 
     proxies: {

package.json

@@ -155,7 +155,7 @@
     "karma-jasmine": "^4.0.1",
     "karma-sourcemap-loader": "^0.3.8",
     "karma-spec-reporter": "0.0.32",
-    "karma-webpack": "^4.0.2",
+    "karma-webpack": "^5.0.0-alpha.5",
     "lint-staged": "^10.5.3",
     "markdown-table": "^2.0.0",
     "markdownlint-cli": "^0.26.0",

webpack.config.test.cjs

@@ -36,7 +36,7 @@ function getConfig(group, { coverage = false } = {}) {
       ...webpackConfig,
       // Karma watches the test entry points, so we don't need to specify
       // them here. Webpack watches dependencies.
-      entry: null,
+      entry: undefined,
       mode: 'development',
       devtool: 'inline-source-map',
       output: {