implementation of jest unit testing

.babelrc

@@ -0,0 +1,19 @@
+{
+  "plugins": ["@babel/plugin-syntax-dynamic-import"],
+  "env": {
+    "test": {
+      "plugins": ["dynamic-import-node"],
+      "presets": [
+        [
+          "@babel/preset-env",
+          {
+            "modules": "commonjs",
+            "targets": {
+              "node": "current"
+            }
+          }
+        ]
+      ]
+    }
+  }
+}

babel.config.js

@@ -1,14 +1,18 @@
-/* eslint-disable */
+/* eslint-env node */
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const fs = require('fs-extra');
+let extend = undefined;
 
-module.exports = api => {
-  return {
-    presets: [
-      [
-        '@quasar/babel-preset-app',
-        api.caller(caller => caller && caller.target === 'node')
-          ? { targets: { node: 'current' } }
-          : {}
-      ]
-    ]
-  }
+/**
+ * The .babelrc file has been created to assist Jest for transpiling.
+ * You should keep your application's babel rules in this file.
+ */
+
+if (fs.existsSync('./.babelrc')) {
+  extend = './.babelrc';
 }
+
+module.exports = {
+  presets: ['@quasar/babel-preset-app'],
+  extends: extend,
+};

jest.config.js

@@ -0,0 +1,64 @@
+const esModules = ['quasar', 'quasar/lang', 'lodash-es'].join('|');
+
+module.exports = {
+  globals: {
+    __DEV__: true,
+    // TODO: Remove if resolved natively
+    // See https://github.com/vuejs/vue-jest/issues/175
+    'vue-jest': {
+      pug: { doctype: 'html' },
+    },
+  },
+  // Jest assumes we are testing in node environment, specify jsdom environment instead
+  testEnvironment: 'jsdom',
+  // noStackTrace: true,
+  // bail: true,
+  // cache: false,
+  // verbose: true,
+  // watch: true,
+  collectCoverage: false,
+  coverageDirectory: '<rootDir>/test/jest/coverage',
+  collectCoverageFrom: [
+    '<rootDir>/src/**/*.vue',
+    '<rootDir>/src/**/*.js',
+    '<rootDir>/src/**/*.jsx',
+  ],
+  // Needed in JS codebases too because of feature flags
+  coveragePathIgnorePatterns: ['/node_modules/', '.d.ts$'],
+  coverageThreshold: {
+    global: {
+      //  branches: 50,
+      //  functions: 50,
+      //  lines: 50,
+      //  statements: 50
+    },
+  },
+  testMatch: [
+    '<rootDir>/test/jest/__tests__/**/*.(spec|test).js',
+    '<rootDir>/src/**/*.jest.(spec|test).js',
+  ],
+  moduleFileExtensions: ['vue', 'js', 'jsx', 'json'],
+  moduleNameMapper: {
+    '^quasar$': 'quasar/dist/quasar.esm.prod.js',
+    '^~/(.*)$': '<rootDir>/$1',
+    '^src/(.*)$': '<rootDir>/src/$1',
+    '^app/(.*)$': '<rootDir>/$1',
+    '^components/(.*)$': '<rootDir>/src/components/$1',
+    '^layouts/(.*)$': '<rootDir>/src/layouts/$1',
+    '^pages/(.*)$': '<rootDir>/src/pages/$1',
+    '^assets/(.*)$': '<rootDir>/src/assets/$1',
+    '^boot/(.*)$': '<rootDir>/src/boot/$1',
+    '.*css$': '@quasar/quasar-app-extension-testing-unit-jest/stub.css',
+  },
+  transform: {
+    '.*\\.vue$': 'vue-jest',
+    '.*\\.js$': 'babel-jest',
+    '.+\\.(css|styl|less|sass|scss|svg|png|jpg|ttf|woff|woff2)$':
+      'jest-transform-stub',
+    // use these if NPM is being flaky, care as hosting could interfere with these
+    // '.*\\.vue$': '@quasar/quasar-app-extension-testing-unit-jest/node_modules/vue-jest',
+    // '.*\\.js$': '@quasar/quasar-app-extension-testing-unit-jest/node_modules/babel-jest'
+  },
+  transformIgnorePatterns: [`node_modules/(?!(${esModules}))`],
+  snapshotSerializers: ['jest-serializer-vue'],
+};

package.json

@@ -8,25 +8,34 @@
   "scripts": {
     "lint": "eslint --ext .js,.vue ./",
     "format": "prettier --write \"**/*.{js,vue,scss,html,md,json}\" --ignore-path .gitignore",
-    "test": "echo \"No test specified\" && exit 0"
+    "test": "echo \"See package.json => scripts for available tests.\" && exit 0",
+    "test:unit": "jest --updateSnapshot",
+    "test:unit:ci": "jest --ci",
+    "test:unit:coverage": "jest --coverage",
+    "test:unit:watch": "jest --watch",
+    "test:unit:watchAll": "jest --watchAll",
+    "serve:test:coverage": "quasar serve test/jest/coverage/lcov-report/ --port 8788",
+    "concurrently:dev:jest": "concurrently \"quasar dev\" \"jest --watch\""
   },
   "dependencies": {
-    "axios": "^0.21.1",
-    "vue-i18n": "^9.0.0",
     "@quasar/extras": "^1.0.0",
+    "axios": "^0.21.1",
     "core-js": "^3.6.5",
     "quasar": "^2.6.0",
     "vue": "^3.0.0",
+    "vue-i18n": "^9.0.0",
     "vue-router": "^4.0.0"
   },
   "devDependencies": {
     "@babel/eslint-parser": "^7.13.14",
+    "@quasar/app-webpack": "^3.0.0",
+    "@quasar/quasar-app-extension-testing-unit-jest": "^3.0.0-alpha.9",
     "eslint": "^8.10.0",
+    "eslint-config-prettier": "^8.1.0",
     "eslint-plugin-vue": "^8.5.0",
     "eslint-webpack-plugin": "^3.1.1",
-    "eslint-config-prettier": "^8.1.0",
     "prettier": "^2.5.1",
-    "@quasar/app-webpack": "^3.0.0"
+    "eslint-plugin-jest": "^25.2.2"
   },
   "browserslist": [
     "last 10 Chrome versions",

quasar.extensions.json

@@ -0,0 +1,8 @@
+{
+  "@quasar/testing-unit-jest": {
+    "babel": "babelrc",
+    "options": [
+      "scripts"
+    ]
+  }
+}

quasar.testing.json

@@ -0,0 +1,5 @@
+{
+  "unit-jest": {
+    "runnerCommand": "jest --ci"
+  }
+}

test/jest/.eslintrc.js

@@ -0,0 +1,10 @@
+module.exports = {
+  extends: [
+    // Removes 'no-undef' lint errors for Jest global functions (`describe`, `it`, etc),
+    //  add Jest-specific lint rules and Jest plugin
+    // See https://github.com/jest-community/eslint-plugin-jest#recommended
+    'plugin:jest/recommended',
+    // Uncomment following line to apply style rules
+    // 'plugin:jest/style',
+  ],
+};

test/jest/.gitignore

@@ -0,0 +1 @@
+coverage/*

test/jest/__tests__/MyButton.spec.js

@@ -0,0 +1,42 @@
+import { describe, expect, it } from '@jest/globals';
+import { installQuasarPlugin } from '@quasar/quasar-app-extension-testing-unit-jest';
+import { mount, shallowMount } from '@vue/test-utils';
+import { QBtn } from 'quasar';
+import MyButton from './demo/MyButton';
+
+// Specify here Quasar config you'll need to test your component
+installQuasarPlugin();
+
+describe('MyButton', () => {
+  it('has increment method', () => {
+    const wrapper = mount(MyButton);
+    const { vm } = wrapper;
+
+    expect(typeof vm.increment).toBe('function');
+  });
+
+  it('can check the inner text content', () => {
+    const wrapper = mount(MyButton);
+    const { vm } = wrapper;
+
+    expect(vm.$el.textContent).toContain('rocket muffin');
+    expect(wrapper.find('.content').text()).toContain('rocket muffin');
+  });
+
+  it('sets the correct default data', () => {
+    const wrapper = mount(MyButton);
+    const { vm } = wrapper;
+
+    expect(typeof vm.counter).toBe('number');
+    expect(vm.counter).toBe(0);
+  });
+
+  it('correctly updates counter when button is pressed', async () => {
+    const wrapper = shallowMount(MyButton);
+    const { vm } = wrapper;
+
+    const button = wrapper.findComponent(QBtn);
+    await button.trigger('click');
+    expect(vm.counter).toBe(1);
+  });
+});

test/jest/__tests__/MyDialog.spec.js

@@ -0,0 +1,30 @@
+import { installQuasarPlugin } from '@quasar/quasar-app-extension-testing-unit-jest';
+import { beforeEach, describe, expect, it } from '@jest/globals';
+import { DOMWrapper, mount } from '@vue/test-utils';
+import MyDialog from './demo/MyDialog';
+
+installQuasarPlugin();
+
+describe('MyDialog', () => {
+  beforeEach(() => {
+    mount(MyDialog, {
+      data: () => ({
+        isDialogOpen: true,
+      }),
+    });
+  });
+
+  it('should mount the document body and expose for testing', () => {
+    const wrapper = new DOMWrapper(document.body);
+
+    expect(wrapper.find('.q-dialog').exists()).toBeTruthy();
+  });
+
+  it('can check the inner text of the dialog', () => {
+    const wrapper = new DOMWrapper(document.body);
+
+    expect(wrapper.find('.q-dialog').html()).toContain(
+      'Custom dialog which should be tested',
+    );
+  });
+});

test/jest/__tests__/demo/MyButton.vue

@@ -0,0 +1,30 @@
+<script>
+import { defineComponent, ref } from 'vue';
+
+export default defineComponent({
+  name: 'MyButton',
+  props: {
+    incrementStep: {
+      type: Number,
+      default: 1,
+    },
+  },
+  setup(props) {
+    const counter = ref(0);
+    const input = ref('rocket muffin');
+    function increment() {
+      counter.value += props.incrementStep;
+    }
+
+    return { counter, input, increment };
+  },
+});
+</script>
+
+<template>
+  <div>
+    <p class="content">{{ input }}</p>
+    <span>{{ counter }}</span>
+    <q-btn class="button" @click="increment()"></q-btn>
+  </div>
+</template>

test/jest/__tests__/demo/MyDialog.vue

@@ -0,0 +1,20 @@
+<template>
+  <q-dialog v-model="isDialogOpen">
+    <q-card>
+      <q-card-section>Custom dialog which should be tested</q-card-section>
+    </q-card>
+  </q-dialog>
+</template>
+
+<script>
+import { defineComponent } from 'vue';
+
+export default defineComponent({
+  name: 'MyDialog',
+  data() {
+    return {
+      isDialogOpen: false,
+    };
+  },
+});
+</script>