五. Mock静态私有方法
被测试类如下所示。
public class MockStaticPrivateMethod {
public static boolean isTrue() {
return returnTrue();
}
private static boolean returnTrue() {
return true;
}
}
被测试类中有一个静态公共方法isTrue(),在isTrue() 方法中会调用MockStaticPrivateMethod的静态私有方法returnTrue()。测试程序如下所示。
@RunWith(PowerMockRunner.class)
@PrepareForTest(MockStaticPrivateMethod.class)
public class PowerMockTest {
@Test
public void mockStaticPrivate() throws Exception {
PowerMockito.mockStatic(MockStaticPrivateMethod.class);
PowerMockito.when(MockStaticPrivateMethod.class, "returnTrue")
.thenReturn(false);
PowerMockito.when(MockStaticPrivateMethod.isTrue()).thenCallRealMethod();
assertThat(MockStaticPrivateMethod.isTrue(), is(false));
}
}
同样测试代码对业务代码造成了入侵,可以使用Whitebox来方便的调用静态私有方法,如下所示。
public class MockStaticPrivateMethod {
private static boolean returnTrue() {
return true;
}
}
@RunWith(PowerMockRunner.class)
@PrepareForTest(MockStaticPrivateMethod.class)
public class PowerMockTest {
@Test
public void mockStaticPrivate() throws Exception {
PowerMockito.mockStatic(MockStaticPrivateMethod.class);
PowerMockito.when(MockStaticPrivateMethod.class, "returnTrue")
.thenReturn(false);
assertThat(Whitebox.invokeMethod(MockStaticPrivateMethod.class, "returnTrue"),
is(false));
}
}
六. Whitebox使用
1. 设置对象私有字段
使用Whitebox可以方便的设置对象(静态)私有字段值。被测试类如下所示。
public class WhiteboxHelp {
private boolean flag = true;
public boolean isTrue() {
return flag;
}
}
被测试类WhiteboxHelp有一个私有字段flag,同时WhiteboxHelp的isTrue() 方法会返回flag的值。测试类如下所示。
public class PowerMockTest {
@Test
public void whiteboxPrivateField() {
WhiteboxHelp whiteboxHelp = new WhiteboxHelp();
Whitebox.setInternalState(whiteboxHelp, "flag", false);
assertThat(whiteboxHelp.isTrue(), is(false));
}
}
仅使用Whitebox时不需要添加@RunWith和@PrepareForTest注解,同时对于上面例子如果flag是静态变量,那么设置静态变量值时需要使用Whitebox.setInternalState(WhiteboxHelp.class, "flag", false)。
特别注意:如果WhiteboxHelp的flag字段是静态的,则无法使用Whitebox设置flag字段的值。
2. 调用私有方法
使用Whitebox也可以方便的调用对象(静态)私有方法。被测试类如下所示。
public class WhiteboxHelp {
private boolean isTrue() {
return true;
}
}
测试类如下所示。
public class PowerMockTest {
@Test
public void whiteboxPrivateMethod() throws Exception {
WhiteboxHelp whiteboxHelp = new WhiteboxHelp();
assertThat(Whitebox.invokeMethod(whiteboxHelp, "isTrue"), is(true));
}
}
对于上面例子,如果isTrue() 是静态私有方法,那么调用静态私有方法时的语句为:assertThat(Whitebox.invokeMethod(WhiteboxHelp.class, "isTrue"), is(true))。
七. Answer-Mock
针对同一方法多次被调用且不同入参需要Mock不同出参的情况,可以使用Answer。
被测试类如下所示。
public class AnswerHelp {
public String convert(int num) {
return StringUtils.EMPTY;
}
}
测试类如下所示。
@RunWith(PowerMockRunner.class)
@PrepareForTest(AnswerHelp.class)
public class PowerMockTest {
@Test
public void answer() {
AnswerHelp answerHelp = PowerMockito.mock(AnswerHelp.class);
Answer<String> answer = new Answer<String>() {
@Override
public String answer(InvocationOnMock invocation) {
int num = (Integer) invocation.getArguments()[0];
if (num == 0) {
return "zero";
} else if (num == 1) {
return "one";
}
return StringUtils.EMPTY;
}
};
PowerMockito.when(answerHelp.convert(anyInt())).thenAnswer(answer);
assertThat(answerHelp.convert(0), is("zero"));
assertThat(answerHelp.convert(1), is("one"));
}
}
其中Answer的泛型类型需要与answer() 方法的返回值类型一致,且通过InvocationOnMock的getArguments() 可以获取mock实例调用的方法所有入参,callRealMethod() 可以调用真实方法,getMethod() 可以获取mock实例调用的方法,getMock() 可以获取mock实例。同时,还可以使用org.mockito.BDDMockito.given来实现相同的效果,如下所示。
public class AnswerHelp {
public String convert(int num) {
return StringUtils.EMPTY;
}
}
@RunWith(PowerMockRunner.class)
@PrepareForTest(AnswerHelp.class)
public class PowerMockTest {
@Test
public void answer() {
AnswerHelp answerHelp = PowerMockito.mock(AnswerHelp.class);
Answer<String> answer = new Answer<String>() {
@Override
public String answer(InvocationOnMock invocation) {
int num = (Integer) invocation.getArguments()[0];
if (num == 0) {
return "zero";
} else if (num == 1) {
return "one";
}
return StringUtils.EMPTY;
}
};
given(answerHelp.convert(anyInt())).willAnswer(answer);
assertThat(answerHelp.convert(0), is("zero"));
assertThat(answerHelp.convert(1), is("one"));
}
}
八. Spy公共方法
先给出一个示例,再对Spy进行解释。被测试类如下所示。
public class SpyPublicMethod {
public boolean isTrue1() {
return true;
}
public boolean isTrue2() {
return true;
}
}
测试类如下所示。
public class PowerMockTest {
@Test
public void spyPublic() {
SpyPublicMethod spy = PowerMockito.spy(new SpyPublicMethod());
PowerMockito.doReturn(false).when(spy).isTrue1();
assertThat(spy.isTrue1(), is(false));
assertThat(spy.isTrue2(), is(true));
}
}
Spy公共方法时需要使用PowerMockito.spy(方法所在类的实例) 获取Spy出来的对象,这里称之为spy实例,不对spy实例进行任何操作的情况下,spy实例与真实实例是完全一样的。同时由于spy实例与真实实例完全一样,因此在对spy实例进行打桩时使用doReturn() 和thenReturn() 是存在差别的:使用doReturn(返回值) 时不会执行真实方式,直接返回返回值;使用thenReturn(返回值) 时会先执行一遍真实方法,然后返回返回值。通常情况下Spy需要配合doReturn() 使用,用于抑制真实方法的执行,防止执行真实方法时报错。
同时,打桩时使用doReturn() 和thenReturn() 的语法存在差别,上面例子中打桩时如果使用的语句为PowerMockito.doReturn(false).when(spy.isTrue1()),会导致编译时正常,运行时报错的现象。下表对打桩时doReturn() 和thenReturn() 的语法进行了对比。
最后,Spy也和Mock一样,可以配合whenNew() 进行使用。
九. Spy私有方法
被测试类如下如下所示。
public class SpyPrivateMethod {
public boolean isTrue() {
return returnTrue();
}
public boolean returnTrue() {
return true;
}
}
测试类如下所示。
@RunWith(PowerMockRunner.class)
@PrepareForTest(SpyPrivateMethod.class)
public class PowerMockTest {
@Test
public void spyPrivate() throws Exception {
SpyPrivateMethod spyPrivateMethod = PowerMockito.spy(new SpyPrivateMethod());
PowerMockito.doReturn(false).when(spyPrivateMethod, "returnTrue");
assertThat(spyPrivateMethod.isTrue(), is(false));
}
}
十. Spy静态方法
1. Spy静态公共方法
被测试类如下所示。
public class SpyStaticPublicMethod {
public static boolean isTrue() {
return true;
}
}
测试类如下所示。
@RunWith(PowerMockRunner.class)
@PrepareForTest(SpyStaticPublicMethod.class)
public class PowerMockTest {
@Test
public void spyStaticPublic() throws Exception {
PowerMockito.spy(SpyStaticPublicMethod.class);
PowerMockito.doReturn(false).when(SpyStaticPublicMethod.class, "isTrue");
assertThat(SpyStaticPublicMethod.isTrue(), is(false));
}
}
2. Spy静态私有方法
被测试类如下所示。
public class SpyStaticPrivateMethod {
public static boolean isTrue() {
return returnTrue();
}
private static boolean returnTrue() {
return true;
}
}
测试类如下所示。
@RunWith(PowerMockRunner.class)
@PrepareForTest(SpyStaticPrivateMethod.class)
public class PowerMockTest {
@Test
public void spyStaticPrivate() throws Exception {
PowerMockito.spy(SpyStaticPrivateMethod.class);
PowerMockito.doReturn(false).when(SpyStaticPrivateMethod.class, "returnTrue");
assertThat(SpyStaticPrivateMethod.isTrue(), is(false));
}
}
十一. Answer-Spy
被测试类如下所示。
public class AnswerHelp {
public String convert(int num) {
return StringUtils.EMPTY;
}
}
测试类如下所示。
@RunWith(PowerMockRunner.class)
@PrepareForTest(AnswerHelp.class)
public class PowerMockTest {
@Test
public void answer() {
AnswerHelp answerHelp = PowerMockito.spy(new AnswerHelp());
Answer<String> answer = new Answer<String>() {
@Override
public String answer(InvocationOnMock invocation) {
int num = (Integer) invocation.getArguments()[0];
if (num == 0) {
return "zero";
} else if (num == 1) {
return "one";
}
return StringUtils.EMPTY;
}
};
PowerMockito.doAnswer(answer).when(answerHelp).convert(anyInt());
assertThat(answerHelp.convert(0), is("zero"));
assertThat(answerHelp.convert(1), is("one"));
}
@Test
public void given_when_then_bdd() {
AnswerHelp answerHelp = PowerMockito.spy(new AnswerHelp());
Answer<String> answer = new Answer<String>() {
@Override
public String answer(InvocationOnMock invocation) {
int num = (Integer) invocation.getArguments()[0];
if (num == 0) {
return "zero";
} else if (num == 1) {
return "one";
}
return StringUtils.EMPTY;
}
};
given(answerHelp.convert(anyInt())).willAnswer(answer);
assertThat(answerHelp.convert(0), is("zero"));
assertThat(answerHelp.convert(1), is("one"));
}
}
总结
本文内容不用于商业目的,如涉及知识产权问题,请权利人联系51Testing小编(021-64471599-8017),我们将立即处理