typescript - 模块导出函数的存根不起作用

Question

我正在尝试从模块中存根导出的函数，以便我可以替换返回值并检查该函数是否已被调用。

我已经创建了一个存根，测试通过了，但不知何故存根没有在函数中使用，并且存根没有被调用一次。

索引.ts

import * as mqtt from 'mqtt'
/*
*/
export const setupConnection = (): mqtt.MqttClient => {
    return mqtt.connect(`${someConfigAddress}:${someConfigPort}`)
}

索引.spec.ts

import * as mqtt from 'mqtt'
import * as mqttClient from 'path/to/index'
import sinon from 'sinon'
import { expect } from 'chai'

describe("Mqtt-Client Tests: ", () => {
    /*
    */
    it('SetupConnection() should call connect once', () => {
        const connectSpy = sinon.stub(mqtt,'connect')
        connectSpy.callsFake(() => this.fakeMqttClient)
        mqttClient.setupConnection()
        expect(connectSpy.called).to.be.true
    })
})

文档中的存根依赖指南也帮不了我

标签： typescriptmocha.jschaisinon

Answer 1

确保"esModuleInterop": true在您的tsconfig.json文件中设置并将import * as mqtt from 'mqtt'语句更改为import mqtt from 'mqtt';

然后，它将正常工作。

例如

index.ts：

import mqtt from 'mqtt';

const someConfigAddress = '127.0.0.1';
const someConfigPort = 6666;

export const setupConnection = (): mqtt.MqttClient => {
  return mqtt.connect(`${someConfigAddress}:${someConfigPort}`);
};

index.test.ts：

import mqtt from 'mqtt';
import * as mqttClient from './';
import sinon from 'sinon';
import { expect } from 'chai';

describe('Mqtt-Client Tests: ', () => {
  it('SetupConnection() should call connect once', () => {
    const connectSpy = sinon.stub(mqtt, 'connect');
    mqttClient.setupConnection();
    expect(connectSpy.called).to.be.true;
  });
});

tsconfig.json：

{
  "compilerOptions": {
    /* Basic Options */
    "target": "ES2015" /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */,
    "module": "commonjs" /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */,
    "lib": [
      "ES2015",
      "ES2016",
      "ES2017",
      "ES2018",
      "ES2019",
      "ES2020",
      "ESNext"
    ] /* Specify library files to be included in the compilation. */,
    // "allowJs": true,                       /* Allow javascript files to be compiled. */
    // "checkJs": true,                       /* Report errors in .js files. */
    // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
    // "declaration": true,                   /* Generates corresponding '.d.ts' file. */
    // "declarationMap": true,                /* Generates a sourcemap for each corresponding '.d.ts' file. */
    // "sourceMap": true,                     /* Generates corresponding '.map' file. */
    // "outFile": "./",                       /* Concatenate and emit output to single file. */
    // "outDir": "./",                        /* Redirect output structure to the directory. */
    // "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
    // "composite": true,                     /* Enable project compilation */
    // "removeComments": true,                /* Do not emit comments to output. */
    // "noEmit": true,                        /* Do not emit outputs. */
    // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
    // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
    // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */

    /* Strict Type-Checking Options */
    // "strict": true /* Enable all strict type-checking options. */,
    "noImplicitAny": false /* Raise error on expressions and declarations with an implied 'any' type. */,
    "strictNullChecks": true /* Enable strict null checks. */,
    "strictFunctionTypes": true /* Enable strict checking of function types. */,
    "strictPropertyInitialization": true /* Enable strict checking of property initialization in classes. */,
    "noImplicitThis": true /* Raise error on 'this' expressions with an implied 'any' type. */,
    "alwaysStrict": true /* Parse in strict mode and emit "use strict" for each source file. */,

    /* Additional Checks */
    // "noUnusedLocals": true,                /* Report errors on unused locals. */
    // "noUnusedParameters": true,            /* Report errors on unused parameters. */
    // "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */
    // "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */

    /* Module Resolution Options */
    // "moduleResolution": "node",            /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
    // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
    // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
    // "typeRoots": ["./node_modules/@types", "./types"] /* List of folders to include type definitions from. */,
    // "types": [] /* Type declaration files to be included in compilation. */,
    // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
    "esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
    // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */

    /* Source Map Options */
    // "sourceRoot": "",                      /* Specify the location where debugger should locate TypeScript files instead of source locations. */
    // "mapRoot": "",                         /* Specify the location where debugger should locate map files instead of generated locations. */
    // "inlineSourceMap": true,               /* Emit a single file with source maps instead of having a separate file. */
    // "inlineSources": true,                 /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */

    /* Experimental Options */
    // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
    // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */
  }
}

测试结果：

  Mqtt-Client Tests: 
    ✓ SetupConnection() should call connect once


  1 passing (4ms)

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |     100 |      100 |     100 |     100 |                   
 index.ts |     100 |      100 |     100 |     100 |                   
----------|---------|----------|---------|---------|-------------------