如何用PowerMockito 测试静态方法

假如有下面一个类DemoStatic，它里面定义了各种静态方法，这些静态方法可能是一些Utilities方法，辅助其它的类。

package mock.demo;

public class DemoStatic {

public static String sayHello() {
return "Hello";
}

public static String saySomething(String word) {
return word;
}

public static void sayAgain() {
System.out.println(getMyWord());
}

private static String getMyWord() {
return "This is my word";
}
}

首先，我们写一个测试类DemoStaticTest.java, 如下：

@RunWith(PowerMockRunner.class)
@PrepareForTest({DemoStatic.class})
public class DemoStaticTest {

}

注意在类的前面要加这个annotation:

@PrepareForTest({DemoStatic.class})

其次，需要在你的项目中加入下面的maven依赖：

<dependency>
<groupId>org.powermock</groupId>
<artifactId>powermock-api-mockito</artifactId>
<version>1.4.10</version>
</dependency>
<dependency>
<groupId>org.powermock</groupId>
<artifactId>powermock-module-junit4</artifactId>
<version>1.4.10</version>
</dependency>

• Mock 无参数的静态方法

@Test
public void testMockSayHello() {
PowerMockito.spy(DemoStatic.class);
PowerMockito.when(DemoStatic.sayHello()).thenReturn("my hello");

System.out.println(DemoStatic.sayHello());  // my hello
}

• Mock 带参数的静态方法

@Test
public void testSaySomething() throws Exception {
PowerMockito.spy(DemoStatic.class);
PowerMockito.when(DemoStatic.class, "saySomething", Mockito.anyString()).thenReturn("something to say!");

System.out.println(DemoStatic.saySomething("say hello")); //something to say!
}

• Mock private 静态方法

@Test
public void testMockPrivate() throws Exception {
PowerMockito.spy(DemoStatic.class);
PowerMockito.when(DemoStatic.class, "getMyWord").thenReturn("Nothing to say");

DemoStatic.sayAgain(); //Nothing to say
}