With Jest, I successfully mocked and implemented a method for the first test case. However, for the second test case (testcase2), I am struggling to implement the same mock method with different input.
jest.mock('../../lib/testService', () => ({
TestService : jest.fn(() => ({
callAPIProd: jest.fn().mockImplementation(() => Promise.resolve([{ DateTime: '2022-01-01'}])),
getAuthToken: jest.fn().mockImplementation(() => Promise.resolve({ data: 'mock token' })),
checkIfExistsInDB: jest.fn().mockImplementation(() => Promise.resolve(false)),
})),
}));
describe('getRates', () => {
it('should insert rates into DB if not already available', async () => {
// Arrange
const req = {} as Request;
const res = {
send: jest.fn(),
} as unknown as Response;
// Act
await integration.getRates(req, res);
// Assert
expect(res.send).toHaveBeenCalledWith('New Rates Received');
});
it('should send response if rates are already available in DB', async () => {
// Arrange
const req = {} as Request;
const res = {
send: jest.fn(),
} as unknown as Response;
// Act
await integration.getRates(req, res);
// Assert
expect(res.send).toHaveBeenCalledWith('Rates already available in DB');
});
});
Within my getRates method, I am invoking the "checkIfExistsInDB" service method which returns true or false. The first test case passed because I mocked the implementation with a false value. Now, I want to remove the current mock implementation and set a new one with a true value. How can I achieve this?
I have attempted to redefine the mock implementation within a specific testcase
it('should send response if rates are already available in DB', async () => {
// Arrange
const req = {} as Request;
const res = {
send: jest.fn(),
} as unknown as Response;
//#1 - Tried to re-define it in this way but it didn't work; it still takes the value as false
jest.mock('../../lib/testService', () => ({
TestService : jest.fn(() => ({
callAPIProd: jest.fn().mockImplementation(() => Promise.resolve([{ DateTime: '2022-01-01'}])),
getAuthToken: jest.fn().mockImplementation(() => Promise.resolve({ data: 'mock token' })),
checkIfExistsInDB: jest.fn().mockImplementation(() => Promise.resolve(true)),
})),
}));
//#2 - Tried to re-define it in this way but it didn't work; it's still taking the value as false
TestService.prototype.checkIfExistsInDB = jest.fn().mockImplementation(() => Promise.resolve(true));
// Act
await integration.getRates(req, res);
// Assert
expect(res.send).toHaveBeenCalledWith('Rates already available in DB');
});