在Java中，如何模拟使用ServiceLoader加载的服务? [英] In Java, how can I mock a service loaded using ServiceLoader?

问题描述

我有一个遗留Java应用程序，该应用程序具有类似这样的代码

I have a legacy Java application that has code something like this

ServiceLoader.load(SomeInterface.class)

，我想提供SomeInterface的模拟实现以供此代码使用.我使用了模拟嘲笑框架.

and I want to provide a mock implementation of SomeInterface for this code to use. I use the mockito mocking framework.

不幸的是，我无法更改旧版代码，也不想静态添加任何内容(例如，向META-INF添加内容).

Unfortunately I am unable to change the legacy code, and I do not wish to add anything statically (eg. adding things to META-INF).

是否有一种简单的方法可以在测试中执行此操作，即在测试运行时?

Is there an easy way to do this from within the test, ie. at runtime of the test?

推荐答案

您可以使用 PowerMockito 与Mockito一起模拟静态方法:

You can use PowerMockito along with Mockito to mock static methods:

@RunWith(PowerMockRunner.class)
@PrepareForTest(ServiceLoader.class)
public class PowerMockingStaticTest
{
    @Mock
    private ServiceLoader mockServiceLoader;

    @Before
    public void setUp()
    {
        PowerMockito.mockStatic(ServiceLoader.class);
        Mockito.when(ServiceLoader.load(Mockito.any(Class.class))).thenReturn(mockServiceLoader);
    }

    @Test
    public void test()
    {
        Assert.assertEquals(mockServiceLoader, ServiceLoader.load(Object.class));
    }
}

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