grafana/packages/grafana-prometheus/src/gcopypaste/public/test/matchers/toEmitValues.test.ts

// Core Grafana history https://github.com/grafana/grafana/blob/v11.0.0-preview/public/test/matchers/toEmitValues.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('toEmitValues matcher', () => {
  describe('failing tests', () => {
    describe('passing null in expect', () => {
      it('should fail', async () => {
        const observable = null as unknown as Observable<number>;

        const rejects = expect(() => expect(observable).toEmitValues([1, 2, 3])).rejects;
        await rejects.toThrow();
      });
    });

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

        const rejects = expect(() => expect(observable).toEmitValues([1, 2, 3])).rejects;
        await rejects.toThrow();
      });
    });

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

        const rejects = expect(() => expect(observable).toEmitValues([1, 2, 3])).rejects;
        await rejects.toThrow();
      });
    });

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

        const rejects = expect(() => expect(observable).toEmitValues([0, 1])).rejects;
        await rejects.toThrow();
      });
    });

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

        const rejects = expect(() => expect(observable).toEmitValues([1, 2, 3])).rejects;
        await rejects.toThrow();
      });
    });

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

        const rejects = expect(() => expect(observable).toEmitValues(['0', '1', '2'])).rejects;
        await rejects.toThrow();
      });
    });

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

        const rejects = expect(() => expect(observable).toEmitValues([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).toEmitValues([0, 1, 2]);
      });
    });

    describe('using nested arrays', () => {
      it('should pass with correct message', async () => {
        const observable = interval(10).pipe(
          map((interval) => [{ text: interval.toString(), value: interval }]),
          take(3)
        );
        await expect(observable).toEmitValues([
          [{ text: '0', value: 0 }],
          [{ text: '1', value: 1 }],
          [{ text: '2', value: 2 }],
        ]);
      });
    });

    describe('using nested objects', () => {
      it('should pass with correct message', async () => {
        const observable = interval(10).pipe(
          map((interval) => ({ inner: { text: interval.toString(), value: interval } })),
          take(3)
        );
        await expect(observable).toEmitValues([
          { inner: { text: '0', value: 0 } },
          { inner: { text: '1', value: 1 } },
          { inner: { text: '2', value: 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;
          })
        ) as unknown as Observable<string | number>;

        await expect(observable).toEmitValues([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);
          })
        ) as unknown as Observable<string | number>;

        await expect(observable).toEmitValues([0, 'an error']);
      });
    });
  });
});