Jasmine Unit Test Abstract class

Question

Is there a way to create a jasmine unit test for an abstract component?

doing

const fixture = TestBed.createComponent(MyAbstractComponent);

Answer 1

Here is what I did to test an angular pipe SafePipe that was using a built in abstract class DomSanitizer.

// 1. Import the pipe/component to be tested
import { SafePipe } from './safe.pipe';
// 2. Import the abstract class
import { DomSanitizer } from '@angular/platform-browser';

// 3. Important step - create a mock class which extends 
// from the base class imported above and add implement 
// the mock methods
class MockDomSanitizer extends DomSanitizer {
  sanitize(): string{
    return 'ANY';
  }
  bypassSecurityTrustHtml(): string{
    return 'ANY'
  }
  bypassSecurityTrustStyle(): string{
    return 'ANY'
  }
  bypassSecurityTrustScript(): string{
    return 'ANY'
  }
  bypassSecurityTrustUrl(): string{
    return 'ANY'
  }
  bypassSecurityTrustResourceUrl(): string{
    return 'ANY'
  }
}

describe('SafePipe', () => {

  it('should return an HTML string', () => {
    // 4. create an instance of pipe class and inject the mocked class above
    let safePipe = new SafePipe(new MockDomSanitizer());

    // 5. Add your asserions as ususal
    expect(safePipe.transform(null, 'html')).toBeTruthy();
    expect(safePipe.transform(null, 'style')).toBeTruthy();
    expect(safePipe.transform(null, 'script')).toBeTruthy();
    expect(safePipe.transform(null, 'url')).toBeTruthy();
    expect(safePipe.transform(null, 'resourceUrl')).toBeTruthy();
    expect(safePipe.transform(null, 'anything')).toContain('anything');
  });

});