PowerMock的 expectNew（）并没有像预期的那样嘲笑构造函数。

constructor java powermock easymock

2022-09-03 12:16:08

我正在尝试学习各种模拟库的来龙去脉，PowerMock（特别是EasyMock扩展）是列表中的下一个。我试图模拟一个构造函数，当我尝试复制它们时，提供的示例没有相同的响应。据我所知，它从不嘲笑构造函数，只是像正常一样继续。

这是测试类：

@RunWith(PowerMockRunner.class)
@PrepareForTest({Writer.class})
public class FaultInjectionSituationTest {

    @Test
    public void testActionFail() throws Exception {
        FaultInjectionSituation fis = new FaultInjectionSituation();
        PowerMock.expectNew(Writer.class, "test")
           .andThrow(new IOException("thrown from mock"));
        PowerMock.replay(Writer.class);
        System.out.println(fis.action());
        PowerMock.verify(Writer.class);
    }

}

我尝试过用EasyMock.isA（String.class）替换“test”，但它产生了相同的结果。

这是故障注入位置：

public class FaultInjectionSituation {

    public String action(){
        Writer w;
        try {
            w = new Writer("test");
        } catch (IOException e) {
            System.out.println("thrown: " + e.getMessage());
            return e.getLocalizedMessage();
        }
        return "returned without throw";
    }
}

“Writer”只不过是一个类的外壳：

public class Writer {
    public Writer(String s) throws IOException {
    }

    public Writer() throws IOException{
    }
}

运行测试时，它会打印出“返回而不引发”，指示从未引发异常。

答案 1

您还需要准备调用构造函数的类，以便 PowerMock 知道期望模拟构造函数调用。请尝试使用以下方法更新代码：

@RunWith(PowerMockRunner.class)
@PrepareForTest({Writer.class, FaultInjectionSituation.class})
public class FaultInjectionSituationTest { 
 // as before
}

答案 2

您需要先创建一个模拟对象：

Writer mockWriter = PowerMock.createMock(Writer.class)
PowerMock.expectNew(Writer.class, "test").andReturn(mockWriter)