JUnit的Powermock：本机库已在另一个类加载器中加载 [英] JUnit & Powermock: Native Library already loaded in another classloader

问题描述

我有一些测试类需要验证是否调用了GLFW函数。但是当我想在IntelliJ中执行所有测试时，我得到了错误：

I have some test classes that need to verify that GLFW-functions were called. But when I want to execute all tests in IntelliJ then I get the error:

Native Library lwjgl.dll already loaded in another classloader

我使用Powermock验证是否已调用静态方法：

I use Powermock to verify that the static methods have been called:

@RunWith(PowerMockRunner.class)
@PrepareForTest({GLFW.class})
public class GlfwWindowImplTest {
    // ...
    @Test
    public void update_swapsBufferAndPollsEvents() {
        GlfwWindowImpl target = new GlfwWindowImpl(1L);
        mockStatic(GLFW.class);

        target.update();

        verifyStatic();
        GLFW.glfwSwapBuffers(1L);
        verifyStatic();
        GLFW.glfwPollEvents();
    }
}

@RunWith(PowerMockRunner.class)
@PrepareForTest({GLFW.class})
public class GlfwWindowSystemImplTest {
    // ...
    @Test(expected = GlfwInitializeException.class)
    public void initialize_throwsExceptionIfGlfwInitFails() {
        GlfwWindowSystemImpl target = new GlfwWindowSystemImpl();
        mockStatic(GLFW.class);
        when(GLFW.glfwInit()).thenReturn(GL_FALSE);

        target.initialize();
    }
}

推荐答案

它回答这篇文章可能有点晚了，但是我遇到了类似的问题，并且我能够使用PowerMock解决它。 PowerMock具有 @SuppressStaticInitializationFor ，可以帮助您解决此问题。以下链接中的禁止静态初始化器部分提供了一个很好的示例：

It may be a bit late to answer this post, but I ran into a similar problem and I was able to solve it with PowerMock. PowerMock has @SuppressStaticInitializationFor that should help you overcome this issue. Section Suppress static initializer in the link below has a nice example about how to do that:

https://github.com/powermock/powermock/wiki/Suppress-Unwanted-Behavior

基本上，在您的情况下，可能会有一个调用 System.loadLibrary（ lwjgl）的类。您需要找到该类。示例：

Basically, in your case, there could be a class that is calling System.loadLibrary("lwjgl"). You need to locate that class. Example:

public class SomeClass {
    ...
    static {
        System.loadLibrary ("lwjgl");
    }
    ...
}

然后在测试中类使用 @SuppressStaticInitializationFor 和该类的完全限定名称：

Then in your test class use @SuppressStaticInitializationFor with the fully qualified name of the class:

@SuppressStaticInitializationFor("com.example.SomeClass")

如果执行loadLibrary调用的类是内部类，则您需要添加 $ InnerClass 以完全限定内部类。示例：

If in case the class doing the loadLibrary call is an inner class, then you need to add $InnerClass to fully qualify the inner class. Example:

public class SomeClass {
    ...
    public static class SomeInnerClass {
        static {
            System.loadLibrary ("lwjgl");
        }
    }
    ...
}

然后您需要使用：

@SuppressStaticInitializationFor("com.example.SomeClass$SomeInnerClass")

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