Question

让我们看一下这段代码：

    public class A {

        public void doSmth() {  // pay attention - void method
           // impl
        }
    }

    public class B {
       private A a_instance; // null

       public void doSmthElse() {
          a_instance.doSmth(); // NPE here without mock
          // also do smth. else
       }
    }

现在，我有B b = new B();，我想测试b.doSmthElse()，但我需要先为a_instance对象创建一个模拟，否则我会得到NullPointerException！如何使用EasyMock或PowerMock实现这一目标？

Answer 1

@Test
public void testDoSomething()
    {
    // setup: sut
    B b = new B();
    A mockA = EasyMock.createMock(A.class);
    b.setA_instance(mockA); // If you have a setter

    // setup: expectations
    mockA.doSmth();

    // exercise
    EasyMock.replay(mockA);
    b.doSmthElse();

    // verify
    EasyMock.verify(mockA);
    }

@Test
public void testDoSomething_setUsingReflection()
    {
    // setup: sut
    B b = new B();
    A mockA = EasyMock.createMock(A.class);
    // Set the collaborator using a Spring reflection utility
    ReflectionTestUtils.setField(b, "a_instance", mockA);

    // setup: expectations
    mockA.doSmth();

    // exercise
    EasyMock.replay(mockA);
    b.doSmthElse();

    // verify
    EasyMock.verify(mockA);
    }

Answer 2

您可以使用

instanceName.methodName();
Easymock.expectLastCall(); //for void methods this is how it is done

instanceName可以是mocked或actualInstance。

如果你可以使方法保持静态，那么使用powermock会更容易

Powermock.mockStatic(ClassNameContainingStaticMethod)

直接模拟所有静态方法

注意事项： - 将方法转换为静态可能会在其他部分出现问题。请小心

希望它有所帮助。一切顺利！

Answer 3

我认为这里不需要PowerMock的原因。您可以通过EasyMock实现这一目标。

@Test
public void testDoSmthElse() {
    A a = EasyMock.createMock(A.class);
    EasyMock.expect(a.doSmth()).andReturn(/*some value */);
    EasyMock.replay(a);

    B b = new B();
    Object whatever = b.doSmthElse();

    assert(); // psuedo-line. Add whatever assertion required
}

注意：导入适当的类

EasyMock + PowerMock：如何模拟领域？

3 个答案: