Bug: Errors are not always compared

[wandertaker]

I'm currently using jest-marbles with typescript in an angular project and encountered a bug in the comparison of errors in marbles. In some cases the errors are just not compared and marbles are asserted as equal even if the errors differ.

Example:

const expectedObservable = hot('^a-#', { a: { test: 1 } }, Error('X'));
const receivedObservable = cold('-a-#', { a: { test: 1 } }, Error('Y'));

expect(receivedObservable).toBeObservable(expectedObservable);

This fails as expected because Error('X') is not equal to Error('Y').

But

const expectedObservable = hot('^#', {}, Error('X'));
const receivedObservable = cold('-#', {}, Error('Y'));  

expect(receivedObservable).toBeObservable(expectedObservable);

succeeds even if Error('X') is not equal to Error('Y'). I would expect this assertion to fail.

I noticed this also happens if numbers are used emitted instead of objects.

const expectedObservable = hot('^a-#', { a: 1 }, Error('X'));
const receivedObservable = cold('-a-#', { a: 1 }, Error('Y'));

are also equal according to jest-marbles.

[pguo-480]

Same issue here with NestJS

[just-jeb]

Interesting, thanks for reporting. I'll definitely check it out.

[jBuchholz590]

Any updates on this? I am trying to check the error returned from a function but it always succeeds:

This is the interesting part of my code (the interceptor should extract the errorList returning in just [1, 2, 3]):

    mockHttpHandler = {handle: () => throwError(new HttpErrorResponse({error: {errorList: [1, 2, 3]}}))};
    expect(interceptor.intercept({} as any, mockHttpHandler)).toBeObservable(cold('#', null, [4, 5, 6]));

[solovevserg]

Any updates? The bug is still here. This code passes but it's incorrect.

expect(cold('#', {}, 'A')).toBeObservable(cold('#', {}, 'B'))

[just-jeb]

Fixed in 3.0.6