單元測試解決方案：
example.js:
import Logger from 'logging-library';
export default function example() {
Logger.error(new Error('Example Error'));
}
example.test.js:
import Logger from 'logging-library';
import example from './example';
jest.mock(
'logging-library',
() => {
return { error: jest.fn() };
},
{ virtual: true },
);
describe('64858662', () => {
afterAll(() => {
jest.resetAllMocks();
});
test('will log an error', () => {
example();
expect(Logger.error).toHaveBeenCalledWith(new Error('Example Error'));
});
});
單元測試結(jié)果：
PASS src/stackoverflow/64858662/example.test.js
64858662
? will log an error (5ms)
------------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
------------|----------|----------|----------|----------|-------------------|
All files | 100 | 100 | 100 | 100 | |
example.js | 100 | 100 | 100 | 100 | |
------------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 4.373s, estimated 12s
