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Mocking function calls within a module

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// f.jsexport function b(){
return 'b';
}
export function a(){
return b();
}

The Naive Approach

test('a', () => {
const f = require('./f');
jest.spyOn(f, 'b').mockReturnValue('c'); expect(f.a()).toBe('c');
// FAILED!
// expected 'c' got 'b'
})

Solution 1 — Splitting The Module Into Different Files


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