Mastering Unit Testing Using Mockito and JUnit

Mock

Mock objects have expectations; a test expects a value from a mock object, and during execution, a mock object returns the expected result. Also, mock objects can keep track of the invocation count, that is, the number of times a method on a mock object is invoked.

The following example is a continuation of the ATM example with a mock version. In the previous example, we stubbed the dispense method of the Dispenser interface to throw an exception; here, we'll use a mock object to replicate the same behavior. We'll explain the syntax in Chapter 4, Progressive Mockito.

public class ATMTest { @Mock Dispenser failingDispenser; @Before public void setUp() throws Exception { MockitoAnnotations.initMocks(this); } @Test public void transaction_is_rolledback_when_hardware_fails() ...