TestBed Configuration (Optional)

As you will see in Testing Components, real-world component testing often relies on the Angular2 testing utility TestBed, which requires some configuration. Most significantly, we need to use TestBed.initTestEnvironment to create a testing platform before we can use unit tests with TestBed. This testing environment would have to be created, destroyed and reset as appropriate before every unit test.

In the angular2-redux-starter, this configuration is done in a tests.configure.ts file and imported into every unit test for easy re-use.

import {
getTestBed,
ComponentFixtureAutoDetect,
TestBed
} from "@angular/core/testing";
import {
BrowserDynamicTestingModule,
platformBrowserDynamicTesting
} from "@angular/platform-browser-dynamic/testing";
export const configureTests = (configure: (testBed: TestBed) => void) => {
const testBed = getTestBed();
if (testBed.platform == null) {
testBed.initTestEnvironment(
BrowserDynamicTestingModule,
platformBrowserDynamicTesting()
);
}
testBed.configureCompiler({
providers: [{ provide: ComponentFixtureAutoDetect, useValue: true }]
});
configure(testBed);
return testBed.compileComponents().then(() => testBed);
};

tests.configure.ts creates the testing platform if it doesn't already exist, compiles the template, and exports configureTests which can then be imported and used in our unit tests.

Here's a look at how it would be used:

import { TestBed } from '@angular/core/testing';
import { ExampleComponent } from './index';
import { configureTests } from '../../tests.configure';
import { AppModule } from '../../modules/app.module';
describe('Component: Example', () => {
let fixture;
beforeEach(done => {
const configure = (testBed: TestBed) => {
testBed.configureTestingModule({
imports: [AppModule],
});
};
configureTests(configure).then(testBed => {
fixture = testBed.createComponent(ExampleComponent);
fixture.detectChanges();
done();
});
});