Configure Jest with projects + coverage output

Author: colinrotherham

Makefile

@@ -44,7 +44,7 @@ test: test-unit test-ui test-lint # Run all tests @Testing
 
 test-unit: # Run unit tests @Testing
 	poetry run pytest -m 'not system'
-	npm test
+	npm test -- --coverage
 
 test-lint: # Lint files @Testing
 	npm run lint

jest.config.js

@@ -1,35 +1,51 @@
 /**
- * Jest config
+ * Jest project config defaults
  *
- * @type {Config}
+ * @type {ProjectConfig}
  */
-export default {
-  collectCoverageFrom: ['**/assets/js/**/*.{js,mjs}'],
-  coverageProvider: 'v8',
-  // testMatch: ['<rootDir>/**/*.unit.test.{js,mjs}'],
-
-  // Enable GitHub Actions reporter UI
-  reporters: ['default', 'github-actions'],
-
+const config = {
   cacheDirectory: '<rootDir>/.cache/jest',
-  coveragePathIgnorePatterns: ['.eslintrc.js', '.test.(js|mjs)'],
+  coveragePathIgnorePatterns: ['.eslintrc.js', '.test.(cjs|js)'],
 
   // Enable Babel transforms until Jest supports ESM and `import()`
   // See: https://jestjs.io/docs/ecmascript-modules
   transform: {
-    '^.+\\.(js|cjs)$': ['babel-jest', { rootMode: 'upward' }]
-  },
-
-  testEnvironment: 'jsdom',
+    '^.+\\.(cjs|js)$': ['babel-jest', { rootMode: 'upward' }]
+  }
+}
 
-  setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],
+/**
+ * Jest config
+ *
+ * @type {Config}
+ */
+export default {
+  collectCoverageFrom: ['**/assets/js/**/*.{cjs,js}'],
+  coverageProvider: 'v8',
+  projects: [
+    {
+      ...config,
+      displayName: 'JavaScript behaviour tests',
+      setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],
+      testEnvironment: 'jsdom',
+      testMatch: ['<rootDir>/**/*.test.{cjs,js}']
+    }
+  ],
 
+  // Reset mocks between tests
   resetMocks: true,
   resetModules: true,
   restoreMocks: true,
-  clearMocks: true
+  clearMocks: true,
+
+  // Enable GitHub Actions reporter UI
+  reporters: ['default', 'github-actions']
 }
 
+/**
+ * @typedef {Exclude<Config['projects'][0], string>} ProjectConfig
+ */
+
 /**
  * @import { Config } from 'jest'
  */