Powermock私有方法

简单笔记下，如有以下待测方法callSumXX，其调用了private方法sumXX

可以直接mock掉callSumXX，传送门：Mockito在Maven junit测试中的应用

如果方法中还有其他待测逻辑等原因不能直接mock掉的话，这里就需要去mock被调用的private方法。

public class Calculator {
    private int sumXX(int a, int b) {
		return a + b;
	}
    
    public int callSumXX(int a, int b){
    	return sumXX(a, b);
    }
}

1.powermock private method的方法

spy被测类：

Calculator powerMock = PowerMockito.spy(new Calculator());

构造返回：

PowerMockito.when(powerMock, "sumXX", 1, 2).thenReturn(2);

断言：

assertEquals(2, powerMock.callSumXX(1, 2));

完整代码如下：

@RunWith(PowerMockRunner.class)
@PrepareForTest({Calculator.class})
public class CalculatorTest {
	
	private Calculator test;

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
	}

	@AfterClass
	public static void tearDownAfterClass() throws Exception {
	}

	@Before
	public void setUp() throws Exception {
		test = new Calculator();
	}

	@After
	public void tearDown() throws Exception {
	}

	@Test
	public void testSumXX() throws Exception {
		Calculator powerMock = PowerMockito.spy(new Calculator());
		PowerMockito.when(powerMock, "sumXX", 1, 2).thenReturn(2);
		assertEquals(2, powerMock.callSumXX(1, 2));
	}
}

测试发现pass了

说明private方法sumXX被成功mock（1+2=2）

2.需要注意的几个问题

a.需要加入@RunWith和@PrepareForTest，见上面的完整代码

b.PowerMockito需要配合Mockito使用，这里版本有对应关系要求：

Mockito                     | PowerMock
------------------------------------------------------------------------------
2.0.0-beta - 2.0.42-beta    |   1.6.5+
------------------------------------------------------------------------------
1.10.19                     |   1.6.4
1.10.8 - 1.10.x             |   1.6.2+
1.9.5-rc1 - 1.9.5           |   1.5.0 - 1.5.6
1.9.0-rc1 & 1.9.0           |   1.4.10 - 1.4.12
1.8.5                       |   1.3.9 - 1.4.9
1.8.4                       |   1.3.7 & 1.3.8
1.8.3                       |   1.3.6
1.8.1 & 1.8.2               |   1.3.5
1.8                         |   1.3
1.7                         |   1.2.5

否则可能出现错误如：
java.lang.NoSuchMethodError:org.mockito.internal.creation.MockSettingsImpl.setMockName(Lorg/mockito/mock/MockName;)Lorg/mockito/internal/creation/settings/CreationSettings

c.maven中powermock的引入：

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <powermock.version>1.6.4</powermock.version>
  </properties>
	<dependency>
      <groupId>org.powermock</groupId>
      <artifactId>powermock-module-junit4</artifactId>
      <version>${powermock.version}</version>
      <scope>test</scope>
   </dependency>
   <dependency>
      <groupId>org.powermock</groupId>
      <artifactId>powermock-api-mockito</artifactId>
      <version>${powermock.version}</version>
      <scope>test</scope>
   </dependency>