I am trying to stub a exported function from a module, so that i can replace the return value and also check if the function has been called.
I already created a stub, the tests runs through, but somehow the stub doesn't get used in the function, and the stub doesn't get called once.
index.ts
import * as mqtt from 'mqtt'
/*
*/
export const setupConnection = (): mqtt.MqttClient => {
return mqtt.connect(`${someConfigAddress}:${someConfigPort}`)
}
index.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
})
})
The stub-dependency guide in the documentation also couldn't help me
Make sure "esModuleInterop": true is set in your tsconfig.json file and change the import * as mqtt from 'mqtt' statement to import mqtt from 'mqtt';
Then, it will work fine.
E.g.
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. */
}
}
test result:
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 |
----------|---------|----------|---------|---------|-------------------