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chore: update takeLast tests
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@benlesh
benlesh committed Feb 26, 2020
1 parent 71ae326 commit 1dca98a
Showing 1 changed file with 131 additions and 93 deletions.
224 changes: 131 additions & 93 deletions spec/operators/takeLast-spec.ts
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import { expect } from 'chai';
import { hot, cold, expectObservable, expectSubscriptions } from '../helpers/marble-testing';
import { takeLast, mergeMap } from 'rxjs/operators';
import { range, ArgumentOutOfRangeError, of } from 'rxjs';

declare function asDiagram(arg: string): Function;
import { TestScheduler } from 'rxjs/testing';
import { assertDeepEquals } from '../helpers/test-helper';

/** @test {takeLast} */
describe('takeLast operator', () => {
asDiagram('takeLast(2)')('should take two values of an observable with many values', () => {
const e1 = cold('--a-----b----c---d--| ');
const e1subs = '^ ! ';
const expected = '--------------------(cd|)';
let rxTest: TestScheduler;

beforeEach(() => {
rxTest = new TestScheduler(assertDeepEquals);
});

it('should take two values of an observable with many values', () => {
rxTest.run(({ cold, expectObservable, expectSubscriptions }) => {
const e1 = cold('--a-----b----c---d--| ');
const e1subs = ' ^-------------------! ';
const expected = '--------------------(cd|)';

expectObservable(e1.pipe(takeLast(2))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(2))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should take last three values', () => {
const e1 = cold('--a-----b----c---d--| ');
const e1subs = '^ ! ';
const expected = '--------------------(bcd|)';
rxTest.run(({ cold, expectObservable, expectSubscriptions }) => {
const e1 = cold(' --a-----b----c---d--| ');
const e1subs = ' ^-------------------! ';
const expected = '--------------------(bcd|)';

expectObservable(e1.pipe(takeLast(3))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(3))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should take all element when try to take larger then source', () => {
const e1 = cold('--a-----b----c---d--| ');
const e1subs = '^ ! ';
const expected = '--------------------(abcd|)';
rxTest.run(({ cold, expectObservable, expectSubscriptions }) => {
const e1 = cold(' --a-----b----c---d--| ');
const e1subs = ' ^-------------------! ';
const expected = '--------------------(abcd|)';

expectObservable(e1.pipe(takeLast(5))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(5))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should take all element when try to take exact', () => {
const e1 = cold('--a-----b----c---d--| ');
const e1subs = '^ ! ';
const expected = '--------------------(abcd|)';
rxTest.run(({ cold, expectObservable, expectSubscriptions }) => {
const e1 = cold(' --a-----b----c---d--| ');
const e1subs = ' ^-------------------! ';
const expected = '--------------------(abcd|)';

expectObservable(e1.pipe(takeLast(4))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(4))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should not take any values', () => {
const e1 = cold('--a-----b----c---d--|');
const expected = '|';
rxTest.run(({ cold, expectObservable }) => {
const e1 = cold(' --a-----b----c---d--|');
const expected = '|';

expectObservable(e1.pipe(takeLast(0))).toBe(expected);
expectObservable(e1.pipe(takeLast(0))).toBe(expected);
});
});

it('should work with empty', () => {
const e1 = cold('|');
const e1subs = '(^!)';
const expected = '|';
rxTest.run(({ cold, expectObservable, expectSubscriptions }) => {
const e1 = cold(' |');
const e1subs = ' (^!)';
const expected = '|';

expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should go on forever on never', () => {
const e1 = cold('-');
const e1subs = '^';
const expected = '-';
rxTest.run(({ cold, expectObservable, expectSubscriptions }) => {
const e1 = cold(' -');
const e1subs = ' ^';
const expected = '-';

expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should be empty on takeLast(0)', () => {
const e1 = hot('--a--^--b----c---d--|');
const e1subs: string[] = []; // Don't subscribe at all
const expected = '|';
rxTest.run(({ hot, expectObservable, expectSubscriptions }) => {
const e1 = hot('--a--^--b----c---d--|');
const expected = ' |';
const e1subs: string[] = []; // Don't subscribe at all

expectObservable(e1.pipe(takeLast(0))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(0))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should take one value from an observable with one value', () => {
const e1 = hot('---(a|)');
const e1subs = '^ ! ';
const expected = '---(a|)';
rxTest.run(({ hot, expectObservable, expectSubscriptions }) => {
const e1 = hot(' ---(a|)');
const e1subs = ' ^--! ';
const expected = '---(a|)';

expectObservable(e1.pipe(takeLast(1))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(1))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should take one value from an observable with many values', () => {
const e1 = hot('--a--^--b----c---d--| ');
const e1subs = '^ ! ';
const expected = '---------------(d|)';
rxTest.run(({ hot, expectObservable, expectSubscriptions }) => {
const e1 = hot('--a--^--b----c---d--| ');
const e1subs = ' ^--------------! ';
const expected = ' ---------------(d|)';

expectObservable(e1.pipe(takeLast(1))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(1))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should error on empty', () => {
const e1 = hot('--a--^----|');
const e1subs = '^ !';
const expected = '-----|';
rxTest.run(({ hot, expectObservable, expectSubscriptions }) => {
const e1 = hot('--a--^----|');
const e1subs = ' ^----!';
const expected = ' -----|';

expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should propagate error from the source observable', () => {
const e1 = hot('---^---#', undefined, 'too bad');
const e1subs = '^ !';
const expected = '----#';
rxTest.run(({ hot, expectObservable, expectSubscriptions }) => {
const e1 = hot('---^---#', undefined, 'too bad');
const e1subs = ' ^---!';
const expected = ' ----#';

expectObservable(e1.pipe(takeLast(42))).toBe(expected, null, 'too bad');
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(42))).toBe(expected, null, 'too bad');
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should propagate error from an observable with values', () => {
const e1 = hot('---^--a--b--#');
const e1subs = '^ !';
const expected = '---------#';
rxTest.run(({ hot, expectObservable, expectSubscriptions }) => {
const e1 = hot('---^--a--b--#');
const e1subs = ' ^--------!';
const expected = ' ---------#';

expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should allow unsubscribing explicitly and early', () => {
const e1 = hot('---^--a--b-----c--d--e--|');
const unsub = ' ! ';
const e1subs = '^ ! ';
const expected = '---------- ';
rxTest.run(({ hot, expectObservable, expectSubscriptions }) => {
const e1 = hot('---^--a--b-----c--d--e--|');
const unsub = ' ---------! ';
const e1subs = ' ^--------! ';
const expected = ' ----------------------';

expectObservable(e1.pipe(takeLast(42)), unsub).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(42)), unsub).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should work with throw', () => {
const e1 = cold('#');
const e1subs = '(^!)';
const expected = '#';
rxTest.run(({ cold, expectObservable, expectSubscriptions }) => {
const e1 = cold(' #');
const e1subs = ' (^!)';
const expected = '#';

expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
expectObservable(e1.pipe(takeLast(42))).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});

it('should throw if total is less than zero', () => {
expect(() => { range(0, 10).pipe(takeLast(-1)); })
.to.throw(ArgumentOutOfRangeError);
expect(() => {
range(0, 10).pipe(takeLast(-1));
}).to.throw(ArgumentOutOfRangeError);
});

it('should not break unsubscription chain when unsubscribed explicitly', () => {
const e1 = hot('---^--a--b-----c--d--e--|');
const unsub = ' ! ';
const e1subs = '^ ! ';
const expected = '---------- ';

const result = e1.pipe(
mergeMap((x: string) => of(x)),
takeLast(42),
mergeMap((x: string) => of(x))
);

expectObservable(result, unsub).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
rxTest.run(({ hot, expectObservable, expectSubscriptions }) => {
const e1 = hot('---^--a--b-----c--d--e--|');
const unsub = ' ---------! ';
const e1subs = ' ^--------! ';
const expected = ' ----------------------';

const result = e1.pipe(
mergeMap((x: string) => of(x)),
takeLast(42),
mergeMap((x: string) => of(x))
);

expectObservable(result, unsub).toBe(expected);
expectSubscriptions(e1.subscriptions).toBe(e1subs);
});
});
});

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