grafana/public/test/matchers/toEmitValuesWith.test.ts

import { interval, Observable, of, throwError } from 'rxjs';
import { map, mergeMap, take } from 'rxjs/operators';

import { OBSERVABLE_TEST_TIMEOUT_IN_MS } from './types';

describe('toEmitValuesWith matcher', () => {
  describe('failing tests', () => {
    describe('passing null in expect', () => {
      it('should fail with correct message', async () => {
        const observable = (null as unknown) as Observable<number>;

        const rejects = expect(() =>
          expect(observable).toEmitValuesWith((received) => {
            expect(received).toEqual([1, 2, 3]);
          })
        ).rejects;

        await rejects.toThrow();
      });
    });

    describe('passing undefined in expect', () => {
      it('should fail with correct message', async () => {
        const observable = (undefined as unknown) as Observable<number>;

        const rejects = expect(() =>
          expect(observable).toEmitValuesWith((received) => {
            expect(received).toEqual([1, 2, 3]);
          })
        ).rejects;

        await rejects.toThrow();
      });
    });

    describe('passing number instead of Observable in expect', () => {
      it('should fail with correct message', async () => {
        const observable = (1 as unknown) as Observable<number>;

        const rejects = expect(() =>
          expect(observable).toEmitValuesWith((received) => {
            expect(received).toEqual([1, 2, 3]);
          })
        ).rejects;

        await rejects.toThrow();
      });
    });

    describe('wrong number of emitted values', () => {
      it('should fail with correct message', async () => {
        const observable = interval(10).pipe(take(3));

        const rejects = expect(() =>
          expect(observable).toEmitValuesWith((received) => {
            expect(received).toEqual([0, 1]);
          })
        ).rejects;

        await rejects.toThrow();
      });
    });

    describe('wrong emitted values', () => {
      it('should fail with correct message', async () => {
        const observable = interval(10).pipe(take(3));

        const rejects = expect(() =>
          expect(observable).toEmitValuesWith((received) => {
            expect(received).toEqual([1, 2, 3]);
          })
        ).rejects;

        await rejects.toThrow();
      });
    });

    describe('wrong emitted value types', () => {
      it('should fail with correct message', async () => {
        const observable = (interval(10).pipe(take(3)) as unknown) as Observable<string>;

        const rejects = expect(() =>
          expect(observable).toEmitValuesWith((received) => {
            expect(received).toEqual(['0', '1', '2']);
          })
        ).rejects;

        await rejects.toThrow();
      });
    });

    describe(`observable that does not complete within ${OBSERVABLE_TEST_TIMEOUT_IN_MS}ms`, () => {
      it('should fail with correct message', async () => {
        const observable = interval(600);

        const rejects = expect(() =>
          expect(observable).toEmitValuesWith((received) => {
            expect(received).toEqual([0]);
          })
        ).rejects;

        await rejects.toThrow();
      });
    });
  });

  describe('passing tests', () => {
    describe('correct emitted values', () => {
      it('should pass with correct message', async () => {
        const observable = interval(10).pipe(take(3));
        await expect(observable).toEmitValuesWith((received) => {
          expect(received).toEqual([0, 1, 2]);
        });
      });
    });

    describe('correct emitted values with throw', () => {
      it('should pass with correct message', async () => {
        const observable = interval(10).pipe(
          map((interval) => {
            if (interval > 1) {
              throw 'an error';
            }

            return interval;
          })
        );

        await expect(observable).toEmitValuesWith((received) => {
          expect(received).toEqual([0, 1, 'an error']);
        });
      });
    });

    describe('correct emitted values with throwError', () => {
      it('should pass with correct message', async () => {
        const observable = interval(10).pipe(
          mergeMap((interval) => {
            if (interval === 1) {
              return throwError('an error');
            }

            return of(interval);
          })
        );

        await expect(observable).toEmitValuesWith((received) => {
          expect(received).toEqual([0, 'an error']);
        });
      });
    });
  });
});