import org.jmock.Expectations; import org.jmock.Mockery; import org.junit.Test; public class CalculatorTest { @Test public void testAdd() { Mockery context = new Mockery(); final Adder adder = context.mock(Adder.class); context.checking(new Expectations() {{ oneOf(adder).add(2, 3); will(returnValue(5)); }}); Calculator calculator = new Calculator(adder); int result = calculator.add(2, 3); assertEquals(5, result); context.assertIsSatisfied(); } }