Powermock：尝试模拟静态时出现 NoClassDefFoundError 类

Question

我正在尝试了解如何使用 Powermock。我正在尝试实现静态方法模拟 here.

的示例

我根据上面的例子创建了这段代码。

然而，我在尝试运行测试时收到 NoClassDefFoundError。

我不知道到底是什么导致了这个错误，因为它主要是复制粘贴的代码。

// imports redacted

@RunWith(PowerMockRunner.class)
@PrepareForTest(Static.class)
public class YourTestCase {
    @Test
    public void testMethodThatCallsStaticMethod() throws Exception {
        // mock all the static methods in a class called "Static"
        PowerMockito.mockStatic(Static.class);
        // use Mockito to set up your expectation
        PowerMockito.when(Static.class, "firstStaticMethod", any()).thenReturn(true);
        PowerMockito.when(Static.class, "secondStaticMethod", any()).thenReturn(321);

        // execute your test
        new ClassCallStaticMethodObj().execute();

        // Different from Mockito, always use PowerMockito.verifyStatic() first
        // to start verifying behavior
        PowerMockito.verifyStatic(Mockito.times(2));
        // IMPORTANT:  Call the static method you want to verify
        Static.firstStaticMethod(anyInt());


        // IMPORTANT: You need to call verifyStatic() per method verification,
        // so call verifyStatic() again
        PowerMockito.verifyStatic(); // default times is once
        // Again call the static method which is being verified
        Static.secondStaticMethod();

        // Again, remember to call verifyStatic()
        PowerMockito.verifyStatic(Mockito.never());
        // And again call the static method.
        Static.thirdStaticMethod();
    }
}

class Static {
    public static boolean firstStaticMethod(int foo) {
        return true;
    }

    public static int secondStaticMethod() {
        return 123;
    }

    public static void thirdStaticMethod() {
    }
}

class ClassCallStaticMethodObj {
    public void execute() {
        boolean foo = Static.firstStaticMethod(2);
        int bar = Static.secondStaticMethod();
    }
}

Answer 1

PowerMock 1.6.6 似乎与 Mockito 2.7 不兼容

我对您的 pom.xml 进行了一些更改。首先我更改了 powermock 版本：

<powermock.version>1.7.0RC2</powermock.version>

然后我把powermock-api-mockito改成了powermock-api-mockito2（第一个不行，好像和Mockito 2.7不兼容）：

<dependency>
    <groupId>org.powermock</groupId>
    <artifactId>powermock-api-mockito2</artifactId>
    <version>${powermock.version}</version>
    <scope>test</scope>
</dependency>

这解决了 NoClassDefFoundError。

无论如何，我仍然必须更改此设置才能使其正常工作：您应该使用 Mockito.when():

而不是 PowerMockito.when()

Mockito.when(Static.firstStaticMethod(anyInt())).thenReturn(true);
Mockito.when(Static.secondStaticMethod()).thenReturn(321);

Answer 2

如上所述，原因是版本兼容性。我正在使用 mockito 3 (3.3.3) 它通过如下声明 powermockito 的依赖关系为我解决了。

      <dependency>
      <groupId>org.powermock</groupId>
      <artifactId>powermock-module-junit4</artifactId>
      <version>2.0.7</version>
      <scope>test</scope>
   </dependency>
   <dependency>
      <groupId>org.powermock</groupId>
      <artifactId>powermock-api-mockito2</artifactId>
      <version>2.0.7</version>
      <scope>test</scope>
   </dependency>

2.0.7 是目前最新的版本

Powermock：尝试模拟静态时出现 NoClassDefFoundError 类

Powermock: NoClassDefFoundError when trying to mock static classes

java

mockito

powermock

powermockito