testing observable that changes

[jmls]

so, I am trying to write a unit test for a state system called akioma. At the heart of the state is the store, which is queried by accessing an Observable selector which returns a slice of the store

status$ = this.select((state) => state.status);

status$ is an observable .

so, the following code reacts to the change of status

import { StateQuery } from '../state.query';

        query.status$
            .pipe(
                tap((result) => {
                    console.log('xxxx', result);
                })
            )
            .subscribe();

Now, I want to a) test the initial state (which should be null) and then b) test the service which changes the status and check that a new value has been sent to the store and observable.

class SystemStateTest {
    static async initialStatus(t) {
        query.status$
            .pipe(
                tap((result) => {
                    console.log('initialStatus', result);
                    t.true(!result);
                })
            )
            .subscribe();
    }

    static async changeOfStatus(t) {
        query.status$
            .pipe(
                filter(Boolean),
                tap((result) => {
                    console.log('changeOfStatus', result);
                    t.deepEqual(result, {
                        initialized: true,
                        sealed: false
                    });
                })
            )
            .subscribe();
        service.setStatus({ initialized: true, sealed: false });
    }
}

test('initialStatus', SystemStateTest.initialStatus);
test('changeOfStatus', SystemStateTest.changeOfStatus);

when I run this test, it passes, but with this message

initialStatus undefined
initialStatus { initialized: true, sealed: false }
changeOfStatus { initialized: true, sealed: false }
  2 tests passed
------------------|---------|----------|---------|---------|-------------------
File              | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
------------------|---------|----------|---------|---------|-------------------
All files         |     100 |      100 |     100 |     100 |                   
 state.query.ts   |     100 |      100 |     100 |     100 |                   
 state.service.ts |     100 |      100 |     100 |     100 |                   
 state.store.ts   |     100 |      100 |     100 |     100 |                   
------------------|---------|----------|---------|---------|-------------------
Done in 2.80s.```

As you can see, the first subscription has not been cancelled. 

how can I cancel this subscription ? I need the `.subscription` at the end , otherwise the test fails with a "never called"

[novemberborn]

I believe our observable support is focused on completion of the observable, but it doesn't do anything fancy otherwise. I suggest you use an async function as the test implementation and manage the observable through there.