Goal

Be able to test printCurrentDate function without changing the method signature. 1.- Test the code with doubles created by you. 2.- Test the code with doubles from a library.

Code to test

public void printCurrentDate() {
	System.out.println(new Date());
}

Learnings

How to build a Mock and Stub manually.

How to use Mockito to generate the doubles.

Tools

Mockito and downloads

Example of mock

@Test
public void should_interact_with_the_mock() {
	Collaborator collaborator = mock(Collaborator.class);		
	MyClass myClass = new MyClass(collaborator);
	
	myClass.run();
	
	verify(collaborator).collaborate();
}

Example of stub

@Test
public void should_retrieve_the_stub_response(){
	Collaborator collaborator = mock(Collaborator.class);		
	String collaboratorResponse = "collaborator response";
	when(collaborator.collaborate()).thenReturn(collaboratorResponse);
	MyClass myClass = new MyClass(collaborator);
	
	String result = myClass.run();
	
	assertEquals(result, collaboratorResponse);
}