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Smart ES6 class mock, Create method proxies on module for easier mocking
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class Abc { | |
func1() { | |
return 'This is function 1' | |
} | |
func2() { | |
return 2; | |
} | |
func3() { | |
return Promise.resolve('three'); | |
} | |
} | |
module.exports = Abc; |
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const IgnoreFunc = ['constructor', '__defineGetter__', '__defineSetter__', '__lookupSetter__', '__lookupGetter__', 'default', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable', 'toLocaleString', 'toString', 'valueOf']; | |
const createMethodProxies = mockedModule => { | |
if (mockedModule && mockedModule.mock) { | |
for (const instance of mockedModule.mock.instances) { | |
for (const method in instance) { | |
if (!IgnoreFunc.includes(method) && !mockedModule[method]) { | |
mockedModule[method] = {}; | |
for (const proxyMethod of ['mockClear', 'mockReset', 'mockRestore', 'mockImplementation', 'mockImplementationOnce', 'mockName', 'mockReturnThis', 'mockReturnValue', 'mockReturnValueOnce', 'mockResolvedValue', 'mockResolvedValueOnce', 'mockRejectedValue', 'mockRejectedValueOnce']) { | |
mockedModule[method][proxyMethod] = (...args) => { | |
for (const instance of mockedModule.mock.instances) { | |
instance[method][proxyMethod](...args); | |
} | |
}; | |
} | |
} | |
} | |
} | |
} | |
}; | |
module.exports = createMethodProxies; |
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const Abc = require('./Abc'); | |
class Xyz { | |
constructor() { | |
this.abc = new Abc(); | |
} | |
funcToTest1() { | |
const result = 'Xyz ->' + this.abc.func1(); | |
return result; | |
} | |
async funcToTest2() { | |
const result = 'Xyz ->' + await this.abc.func2(); | |
return result; | |
} | |
async funcToTest3() { | |
const result = 'Xyz ->' + await this.abc.func3(); | |
return result; | |
} | |
} | |
module.exports = Xyz; |
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const createMethodProxies = require('./createMethodProxies'); | |
const Abc = require('./Abc'); | |
const Xyz = require('./Xyz'); | |
jest.mock('./Abc'); | |
describe('Xyz', () => { | |
let xyz; | |
beforeEach(() => { | |
xyz = new Xyz(); | |
createMethodProxies(Abc); | |
}) | |
it('should return correct value on funcToTest1', () => { | |
Abc.func1.mockReturnValueOnce('test123'); | |
const actual = xyz.funcToTest1(); | |
expect(actual).toEqual('Xyz ->test123'); | |
}); | |
it('should return correct value on funcToTest2', async () => { | |
Abc.func2.mockReturnValueOnce(Promise.resolve(444)); | |
const actual = await xyz.funcToTest2(); | |
expect(actual).toEqual('Xyz ->444'); | |
}); | |
it('should return correct value on funcToTest3', async () => { | |
Abc.func3.mockReturnValueOnce(Promise.resolve('four')); | |
const actual = await xyz.funcToTest3(); | |
expect(actual).toEqual('Xyz ->four'); | |
}); | |
}); |
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Abc.mock.instance[x].method.mockReturnValueOnce
doAbc.mockReturnValueOnce