Is there an alternative to mock objects in unit testing?

Question

It's a Java (using JUnit) enterprise Web application with no mock objects pre-built, and it would require a vast amount of time not estimated to create them. Is there a testing paradigm that would give me "some" test coverage, but not total coverage?

Answer 1

Do you have real world data you can import into your testbed to use as your 'mock objects' that would be quick

Answer 2

I think the opposite is hard - to find a testing methodology that gives you total coverage, if at all possible in most cases.

Answer 3

Have you tried a dynamic mocking framework such as EasyMock? It does not require you to "create" a Mock object in that you would have to write the entire class - you specify the behavior you want within the test itself.

An example of a class that uses a UserService to find details about a User in order to log someone in:

//Tests what happens when a username is found in the backend
public void testLoginSuccessful() {
    UserService mockUserService = EasyMock.createMock(UserService.class);

    EasyMock.expect(mockUserService.getUser("aUsername")).andReturn(new User(...));
    EasyMock.replay(mockUserService);

    classUnderTest.setUserService(mockUserService);

    boolean isLoggedIn = classUnderTest.login("username");
    assertTrue(isLoggedIn);
}

//Tests what happens when the user does not exist
public void testLoginFailure() {
    UserService mockUserService = EasyMock.createMock(UserService.class);

    EasyMock.expect(mockUserService.getUser("aUsername")).andThrow(new UserNotFoundException());
    EasyMock.replay(mockUserService);

    classUnderTest.setUserService(mockUserService);

    boolean isLoggedIn = classUnderTest.login("username");
    assertFalse(isLoggedIn);
}

Answer 4

(1) Alternatives to unit-testing (and mocks) include integration testing (with dbUnit) and FIT testing. For more, see my answer here.

(2) The mocking framework Mockito is outstanding. You wouldn't have to "pre-build" any mocks. It is relatively easy to introduce into a project.

Answer 5

What about JMock which can mock not only interfaces but also whole objects?

Answer 6

u can try easymock.. http://easymock.org/Documentation.html

Answer 7

I would echo what others are saying about EasyMock. However, if you have a codebase where you need to mock things like static method calls, final classes or methods, etc., then give JMockit a look.

Answer 8

Well, one easy, if not the easiest, way to get an high level of code coverage is to write the code test-first, following Test-Driven Development (TDD). Now that the code exists, without unit tests, it can be deemed as legacy code.

You could either write end-to-end test, external to your application, those won't be unit tests, but they can be written without resorting to any kind of mock. Or you could write unit tests that span over multiple classes, and only mock the classes that gets in the way of your unit tests.