replace karma by jest

Author: Patrick Creutzburg

angular.json

@@ -83,12 +83,10 @@
           }
         },
         "test": {
-          "builder": "@angular-devkit/build-angular:karma",
+          "builder": "@angular-builders/jest:run",
           "options": {
-            "main": "src/test.ts",
             "polyfills": "src/polyfills.ts",
             "tsConfig": "tsconfig.spec.json",
-            "karmaConfig": "karma.conf.js",
             "assets": [
               "src/favicon.ico",
               "src/assets"
@@ -129,4 +127,4 @@
     }
   },
   "defaultProject": "design-patterns-in-angular"
-}
+}

jest.config.js

@@ -0,0 +1,7 @@
+module.exports = {
+  moduleNameMapper: {
+    '@core/(.*)': '<rootDir>/src/app/core/$1',
+  },
+  preset: 'jest-preset-angular',
+  setupFilesAfterEnv: ['<rootDir>/setup-jest.ts'],
+};