使用Rewire和TypeScript

时间:2016-10-11 12:12:09

标签: unit-testing typescript react-native

我正在使用TypeScript处理React-Native项目。要编写我的单元测试,我想使用babel-plugin-rewire来模拟我的模块导入。但是,在从ES6转换为ES5时,TypeScript会在导入结尾处添加_1后缀,这会破坏我的测试代码。

请考虑以下事项:

import Test from 'test-file';

这可能会被TypeScript转换为:

var test_file_1 = require('test-file');

要使用Rewire插件模拟Test类,我必须写:

ComponentToTest.__Rewire__('Test', TestMock);

但由于导入已重命名,因此会中断。

虽然这是by design,但我很想知道是否有任何解决方法。

感谢。

1 个答案:

答案 0 :(得分:7)

我不了解Babel-Plugin-Rewire,但如果您单独使用TypeScript和Rewire,包括将ES6模块编译到ES5,您可以轻松地直接模拟生成的文件导入。

即。这应该有效:

ComponentToTest.__set__('test_file_1', { default: TestMock });

那取决于_1后缀,后者可能会在以后的TypeScript版本中发生变化,或者您对TypeScript代码本身进行了某些更改。我认为这风险相当低。

Full Rewire + TS示例:

Component.ts:

import DefaultComponent from "other-component";
import { IndividuallyExportedComponent } from "yet-another-component";

// ... Do something worth testing

组件的Test.ts:

import rewire = require("rewire");
let RewiredComponent = rewire("../src/Component");

let defaultMock = { /* Make a mock of your dependency */ };
RewiredComponent.__set__('other_component_1', {
    default: defaultComponentMock
});

let individuallyExportedMock = { /* Make a mock of your dependency */ };
RewiredComponent.__set__('yet_another_component_1', {
    IndividuallyExportedComponent: individuallyExportedMock
});

// RewiredComponent has the wrong type now. YMMV, but I'm doing type-wrangling
// that looks something like:

import * as RealComponent from "../src/Component";
let Component: typeof RealComponent & typeof RewiredComponent = <any> RewiredComponent;

// 'Component' now has the same type as the real module, plus the
// .__set__ etc methods from Rewire.