尝试使用javascript进行catch单元测试(jest)

Question

我有以下脚本employeeJobTransferServiceLive.js:

const createJobTrasferSetPayloadOutput = async (jobTransferSetPayload) => {
const file = './output/jobTransferSetPayload.json';
try {
await fs.writeFile(file, JSON.stringify(jobTransferSetPayload, null, 4), { overwrite: false });
return JSON.stringify(jobTransferSetPayload);
} catch (err) {
return err;
}
};

所以我创建了以下单元测试employeeJobTransferServiceLive.test.js:

const empJobTransferSrvc = require('../../../libs/employeeJobTransferSet/employeeJobTransferServiceLive');
jest.mock('fs', () => ({
promises: {
writeFile: jest.fn(),
},
}));
describe('sendWFDRequest is called', () => {
afterEach(() => {
jest.resetModules();
jest.clearAllMocks();
});
it('Create and Write to the file', async () => {
const result = await empJobTransferSrvc.createJobTrasferSetPayloadOutput(jobTransferSetPayload);
expect(JSON.parse(result)[0]).toEqual(jobTransferSetPayload[0]);
expect(result).not.toBeNull();
});
});

编译器抱怨行返回错误的测试覆盖率问题；捕获后。我不知道如何创建单元测试来覆盖它

Answer 1

也许这不是最好的答案，但至少它对我来说很好

const fs = require('fs').promises;
const empJobTransferSrvc = require('../../../libs/employeeJobTransferSet/employeeJobTransferServiceLive');
jest.mock('fs', () => ({
promises: {
writeFile: jest.fn(),
},
}));
describe('sendWFDRequest is called', () => {
afterEach(() => {
jest.resetModules();
jest.clearAllMocks();
});
it('Create and Write to the file', async () => {
const result = await empJobTransferSrvc.createJobTrasferSetPayloadOutput(jobTransferSetPayload);
expect(JSON.parse(result)[0]).toEqual(jobTransferSetPayload[0]);
expect(result).not.toBeNull();
});
it('should handle a writeFile error', async () => {
jest.spyOn(fs, 'writeFile').mockRejectedValue(new Error('something went wrong'));
try {
await empJobTransferSrvc.createJobTrasferSetPayloadOutput(jobTransferSetPayload, logger);
} catch (error) {
expect(error.message).toEqual('Error: something went wrong');
}
});
});