angular-docs-cn/modules/@angular/common/test/pipes/i18n_plural_pipe_spec.ts

import {
  ddescribe,
  describe,
  it,
  iit,
  xit,
  expect,
  beforeEach,
  afterEach
} from '@angular/core/testing/testing_internal';

import {I18nPluralPipe} from '@angular/common';
import {PipeResolver} from '@angular/compiler/src/pipe_resolver';

export function main() {
  describe("I18nPluralPipe", () => {
    var pipe;
    var mapping = {'=0': 'No messages.', '=1': 'One message.', 'other': 'There are some messages.'};
    var interpolatedMapping =
        {'=0': 'No messages.', '=1': 'One message.', 'other': 'There are # messages, that is #.'};

    beforeEach(() => { pipe = new I18nPluralPipe(); });

    it('should be marked as pure',
       () => { expect(new PipeResolver().resolve(I18nPluralPipe).pure).toEqual(true); });

    describe("transform", () => {
      it("should return 0 text if value is 0", () => {
        var val = pipe.transform(0, mapping);
        expect(val).toEqual('No messages.');
      });

      it("should return 1 text if value is 1", () => {
        var val = pipe.transform(1, mapping);
        expect(val).toEqual('One message.');
      });

      it("should return other text if value is anything other than 0 or 1", () => {
        var val = pipe.transform(6, mapping);
        expect(val).toEqual('There are some messages.');
      });

      it("should interpolate the value into the text where indicated", () => {
        var val = pipe.transform(6, interpolatedMapping);
        expect(val).toEqual('There are 6 messages, that is 6.');
      });

      it("should use 'other' if value is undefined", () => {
        var messageLength;
        var val = pipe.transform(messageLength, interpolatedMapping);
        expect(val).toEqual('There are  messages, that is .');
      });

      it("should not support bad arguments",
         () => { expect(() => pipe.transform(0, 'hey')).toThrowError(); });
    });

  });
}