Is there a way to create a jasmine unit test for an abstract component?
doing
const fixture = TestBed.createComponent(MyAbstractComponent);
says, "cannot assign an abstract constructor type to a non-abstract constructor type"
I tried some searching but nothing comes up.
You can create a simple class in your test file which extends from abstract class (do not forget to mock abstract methods), than just test its non abstract methods. Let's say we have MyAbstractClass:
export abstract class MyAbstractClass {
sum(a: number, b: number): number {
return a + b;
}
abstract calc1(): void;
abstract calc2(): void;
}
and then in spec file we can just create a new derived class:
class MyClass extends MyAbstractClass {
// just mock any abstract method
calc1(): void {
return;
}
calc2(): void {
return;
}
}
So now we can write tests for non-abstract methods:
describe('MyAbstractClass', () => {
let myClass: MyClass;
beforeEach(() => {
myClass = new MyClass();
});
it('sum two args', () => {
const a = 1, b = 2;
const sum = myClass.sum(a, b);
expect(sum).toBe(3);
});
});
Also created a stackblitz example of this test example.
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');
});
});