PowerMock 不会模拟静态方法在 Spring-Boot 应用程序中抛出异常

Question

我意识到有很多非常相似的问题。我已经完成了所有这些，但我仍然无法使我的代码正常工作。

我在 Spring-Boot 应用程序中定义了一个服务，就像这样：

@Service
public class FileStorageService {
    private final Path fileStorageLocation;

    @Autowired
    public FileStorageService(final FileStorageProperties fileStorageProperties) {
            //FileStorageProperties is a very simple class that right now just holds one String value
            this.fileStorageLocation = Paths.get(fileStorageProperties.getUploadDir())
                .toAbsolutePath()
                .normalize();

        try {
            Files.createDirectories(fileStorageLocation);
        } catch (IOException e) {
            // FileStorageException is my custom, runtime exception
            throw new FileStorageException("Failed to create directory for stored files", e);
        }
    }
}

我想测试场景，当目录创建失败时，我需要模拟方法 Files.createDirectories()。我的测试 class 看起来像这样：

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

import java.io.IOException;
import java.nio.file.Files;

@RunWith(PowerMockRunner.class)
@PrepareForTest({Files.class})
public class FileStorageServiceTest {
    private static final String UPLOAD_DIR = "uploadDir";

    @Test(expected = FileStorageException.class)
    public void some_test() throws IOException {
        PowerMockito.mockStatic(Files.class);
        PowerMockito.when(Files.createDirectories(Mockito.any())).thenThrow(new IOException());

        new FileStorageService(createFileStorageProperties());
    }

    private FileStorageProperties createFileStorageProperties() {
        final FileStorageProperties fileStorageProperties = new FileStorageProperties();
        fileStorageProperties.setUploadDir(UPLOAD_DIR);
        return fileStorageProperties;
    }
}

我相信我遵循了我阅读过的教程和问题中的每一步。我使用：

@RunWith(PowerMockRunner.class),
@PrepareForTest({Files.class}),
PowerMockito.mockStatic(Files.class),
和PowerMockito.when(Files.createDirectories(Mockito.any())).thenThrow(new IOException());.

仍然，在测试期间没有抛出异常并且失败。非常感谢您的帮助，因为我觉得我错过了一些非常简单的东西，只是看不到它。

Answer 1

发件人：https://github.com/powermock/powermock/wiki/Mock-System

Normally you would prepare the class that contains the static methods (let's call it X) you like to mock but because it's impossible for PowerMock to prepare a system class for testing so another approach has to be taken. So instead of preparing X you prepare the class that calls the static methods in X!

基本上，我们模拟 class 对系统 class 的使用，而不是不可模拟的系统 class 本身。

@PrepareForTest({Files.class})

在不模拟任何系统的情况下执行此操作的另一种非 Powermock 方法 class 是创建一个辅助方法，@Spy 原始 class，并专门模拟该辅助方法以抛出异常。

when(spy.doSomethingWithSystemClasses()).thenThrow(new Exception("Foo");

PowerMock 不会模拟静态方法在 Spring-Boot 应用程序中抛出异常

PowerMock won't mock static method to throw an Exception in a Spring-Boot application

java

spring-boot

mockito

powermockito