angular-cn/packages/common/test/pipes/slice_pipe_spec.ts

122 lines
4.1 KiB
TypeScript

/**
* @license
* Copyright Google LLC All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {CommonModule, SlicePipe} from '@angular/common';
import {Component} from '@angular/core';
import {async, TestBed} from '@angular/core/testing';
import {expect} from '@angular/platform-browser/testing/src/matchers';
{
describe('SlicePipe', () => {
let list: number[];
let str: string;
let pipe: SlicePipe;
beforeEach(() => {
list = [1, 2, 3, 4, 5];
str = 'tuvwxyz';
pipe = new SlicePipe();
});
describe('supports', () => {
it('should support strings', () => {
expect(() => pipe.transform(str, 0)).not.toThrow();
});
it('should support lists', () => {
expect(() => pipe.transform(list, 0)).not.toThrow();
});
it('should support readonly lists', () => {
expect(() => pipe.transform(list as ReadonlyArray<number>, 0)).not.toThrow();
});
it('should not support other objects',
// this would not compile
// so we cast as `any` to check that it throws for unsupported objects
() => {
expect(() => pipe.transform({} as any, 0)).toThrow();
});
});
describe('transform', () => {
it('should return null if the value is null', () => {
expect(pipe.transform(null, 1)).toBe(null);
});
it('should return undefined if the value is undefined', () => {
expect(pipe.transform(undefined, 1)).toBe(undefined);
});
it('should return all items after START index when START is positive and END is omitted',
() => {
expect(pipe.transform(list, 3)).toEqual([4, 5]);
expect(pipe.transform(str, 3)).toEqual('wxyz');
});
it('should return last START items when START is negative and END is omitted', () => {
expect(pipe.transform(list, -3)).toEqual([3, 4, 5]);
expect(pipe.transform(str, -3)).toEqual('xyz');
});
it('should return all items between START and END index when START and END are positive',
() => {
expect(pipe.transform(list, 1, 3)).toEqual([2, 3]);
expect(pipe.transform(str, 1, 3)).toEqual('uv');
});
it('should return all items between START and END from the end when START and END are negative',
() => {
expect(pipe.transform(list, -4, -2)).toEqual([2, 3]);
expect(pipe.transform(str, -4, -2)).toEqual('wx');
});
it('should return an empty value if START is greater than END', () => {
expect(pipe.transform(list, 4, 2)).toEqual([]);
expect(pipe.transform(str, 4, 2)).toEqual('');
});
it('should return an empty value if START greater than input length', () => {
expect(pipe.transform(list, 99)).toEqual([]);
expect(pipe.transform(str, 99)).toEqual('');
});
it('should return entire input if START is negative and greater than input length', () => {
expect(pipe.transform(list, -99)).toEqual([1, 2, 3, 4, 5]);
expect(pipe.transform(str, -99)).toEqual('tuvwxyz');
});
it('should not modify the input list', () => {
expect(pipe.transform(list, 2)).toEqual([3, 4, 5]);
expect(list).toEqual([1, 2, 3, 4, 5]);
});
});
describe('integration', () => {
@Component({selector: 'test-comp', template: '{{(data | slice:1).join(",") }}'})
class TestComp {
data: any;
}
beforeEach(() => {
TestBed.configureTestingModule({declarations: [TestComp], imports: [CommonModule]});
});
it('should work with mutable arrays', async(() => {
const fixture = TestBed.createComponent(TestComp);
const mutable: number[] = [1, 2];
fixture.componentInstance.data = mutable;
fixture.detectChanges();
expect(fixture.nativeElement).toHaveText('2');
mutable.push(3);
fixture.detectChanges();
expect(fixture.nativeElement).toHaveText('2,3');
}));
});
});
}