模拟其他静态方法中的静态方法

Question

我有一个小类，它返回由位于我的类路径中的message_xx.properties填充的属性对象：

public class PropertiesUtils {
  public static Properties loadProperties(Locale locale) {
    try {
      ClassLoader loader = getClassLoader();
      Properties properties = new Properties();
      String filePath = "messages_" + locale.getLanguage().toLowerCase() + ".properties";
      InputStream is = loader.getResourceAsStream(filePath);
      properties.load(is);
      is.close();
      return properties;
    } catch (Exception e) {
      log.error("Error loading properties by locale "+locale, e);
      return null;
    }
  }
  public static ClassLoader getClassLoader(){
    return PropertiesUtils.class.getClassLoader();
  }
}

一切正常，但我想为此创建单元测试。我想模拟方法"getClassLoader"以返回一些我想要的junit测试上下文中的特定输入流。

@RunWith(PowerMockRunner.class)
@PrepareForTest(value=PropertiesUtils.class)
public class PropertiesUtilsTest {
    @Mock
    private Locale zuluLocale;
    @Mock
    private Locale etruscanLocale;
    @Mock
    private ClassLoader mockClassLoader;
    @Before
    public void init(){
        Mockito.when(zuluLocale.getLanguage()).thenReturn("zulu");
        Mockito.when(etruscanLocale.getLanguage()).thenReturn("etruscan");
        Mockito.when(mockClassLoader.getResourceAsStream("messages_zulu.properties")).thenReturn(IOUtils.toInputStream("2=esal"));
        Mockito.when(mockClassLoader.getResourceAsStream("messages_etruscan.properties")).thenReturn(IOUtils.toInputStream("2=ezimbili"));
        PowerMockito.mockStatic(PropertiesUtils.class);
        PowerMockito.when(PropertiesUtils.getClassLoader()).thenReturn(mockClassLoader);
    }
    @After
    public void finalize(){
        zuluLocale = null;
        etruscanLocale = null;
    }
    @Test
    public void loadPropertiesTest(){
        Assert.assertNull(PropertiesUtils.loadProperties(new Locale("en")));
        Assert.assertNotNull(PropertiesUtils.loadProperties(zuluLocale));
        Assert.assertNotNull(PropertiesUtils.loadProperties(etruscanLocale));
        Assert.assertEquals("esal", PropertiesUtils.loadProperties(zuluLocale).getProperty("2"));
        Assert.assertEquals("ezimbili", PropertiesUtils.loadProperties(etruscanLocale).getProperty("2"));
    }
}

此测试失败，因为断言失败错误在行中：

Assert.assertNotNull(PropertiesUtils.loadProperties(zuluLocale));

Answer 1

好吧，这是假的，问题，我需要做的就是：

PowerMockito.when(PropertiesUtils.loadProperties(zuluLocale)).thenCallRealMethod();
PowerMockito.when(PropertiesUtils.loadProperties(etruscanLocale)).thenCallRealMethod();