使用Jasmine单元测试过滤器组件

Question

我创建了一个组件，用于过滤掉传递给它的字符串。我正在尝试为此编写单元测试，它引发了与构造函数有关的错误。请帮我。import angular from 'angular';import filter from "./format-string.filter"angular.module( "filters.truncateString", [] ).filter( "truncateString", () => filter );class TruncateString { filter(val){    const accValue = val.split('YYYY');    const firstValue= accValue[1].replace(/^(|-?\d+)$/, '');    return `${accValue[0]} ${firstValue} AAA`; }}export default TruncateString .filter;`我写的测试是import angular from 'angular';import 'angular-mocks';import TruncateString from './format-string.filter';describe('TruncateString filter', () => {let controller, filter;beforeEach(angular.mock.module('filters.TruncateString'));controller = new TruncateString();beforeEach(inject(function(_$filter_){    filter = _$filter_;}));it('Checking whether the function is returning formatted string', () => {    const result = controller.filter('123YYY3213123');    expect(result).toHaveBeenCalledWith('123 YYY ... 23');});});

Answer 1

这是测试过滤器的方法

describe('Test My Filter', () => {

  let $filter;

  beforeEach(() => {

    module('filters.TruncateString');

    inject((_$filter_) => {

      $filter = _$filter_;

    });

  });

  it('should test filter behavior', () => {

    let result = $filter('truncateString')('testval');

    expect(result).toEqual('expectedval');

  });

});