feat(jest): add createMock (#30)

Author: timdeschryver

projects/testing-library/src/jest-utils/create-mock.ts

@@ -0,0 +1,37 @@
+import { Type, Provider } from '@angular/core';
+
+export type Mock<T> = T & { [K in keyof T]: T[K] & jest.Mock };
+
+export function createMock<T>(type: Type<T>): Mock<T> {
+  const mock: any = {};
+
+  function mockFunctions(proto: any) {
+    if (!proto) {
+      return;
+    }
+
+    for (const prop of Object.getOwnPropertyNames(proto)) {
+      if (prop === 'constructor') {
+        continue;
+      }
+
+      const descriptor = Object.getOwnPropertyDescriptor(proto, prop);
+      if (typeof descriptor.value === 'function') {
+        mock[prop] = jest.fn();
+      }
+    }
+
+    mockFunctions(Object.getPrototypeOf(proto));
+  }
+
+  mockFunctions(type.prototype);
+
+  return mock;
+}
+
+export function provideMock<T>(type: Type<T>): Provider {
+  return {
+    provide: type,
+    useFactory: () => createMock(type),
+  };
+}

projects/testing-library/src/jest-utils/index.ts

@@ -1 +1,2 @@
 export * from './configure-test-suite';
+export * from './create-mock';

projects/testing-library/tests/jest-utils/create-mock.spec.ts

@@ -0,0 +1,52 @@
+import { createMock, provideMock, Mock } from '../../src/jest-utils';
+import { render } from '../../src/public_api';
+import { Component } from '@angular/core';
+import { TestBed } from '@angular/core/testing';
+
+class FixtureService {
+  constructor(private foo: string, public bar: string) {}
+
+  print() {
+    console.log(this.foo, this.bar);
+  }
+}
+
+@Component({
+  selector: 'fixture',
+  template: `
+    <button (click)="print()">Print</button>
+  `,
+})
+export class FixtureComponent {
+  constructor(private service: FixtureService) {}
+
+  print() {
+    this.service.print();
+  }
+}
+
+it('mocks all functions', () => {
+  const mock = createMock(FixtureService);
+  expect(mock.print.mock).toBeDefined();
+});
+
+it('provides a mock service', async () => {
+  const { click, getByText } = await render(FixtureComponent, {
+    providers: [provideMock(FixtureService)],
+  });
+  const service = TestBed.get<FixtureService>(FixtureService);
+
+  click(getByText('Print'));
+  expect(service.print).toHaveBeenCalledTimes(1);
+});
+
+it('is possible to write a mock implementation', async done => {
+  const { click, getByText } = await render(FixtureComponent, {
+    providers: [provideMock(FixtureService)],
+  });
+
+  const service = TestBed.get<FixtureService>(FixtureService) as Mock<FixtureService>;
+  service.print.mockImplementation(() => done());
+
+  click(getByText('Print'));
+});

projects/testing-library/tests/providers/module-provider.spec.ts

@@ -1,7 +1,6 @@
 import { Injectable } from '@angular/core';
 import { Component } from '@angular/core';
 import { render } from '../../src/public_api';
-import { TestBed } from '@angular/core/testing';
 
 // tslint:disable: no-use-before-declare
 test('shows the service value', async () => {