import static org.easymock.EasyMock.*; public interface Calculator { int add(int a, int b); } public class CalculatorTest { public static void main(String[] args) { Calculator mockCalculator = createMock(Calculator.class); expect(mockCalculator.add(2, 3)).andReturn(5); replay(mockCalculator); int result = mockCalculator.add(2, 3); verify(mockCalculator); assert result == 5; } }