问题描述

在使用 Mockito 和 JUnit4 为以下代码编写单元测试时需要帮助，

Need help to write a unit test for the below code using Mockito and JUnit4,

public class MyFragmentPresenterImpl { 
      public Boolean isValid(String value) {
        return !(TextUtils.isEmpty(value));
      }
}

我尝试了以下方法:MyFragmentPresenter mMyFragmentPresenter

I tried below method: MyFragmentPresenter mMyFragmentPresenter

@Before
public void setup(){
    mMyFragmentPresenter=new MyFragmentPresenterImpl();
}

@Test
public void testEmptyValue() throws Exception {
    String value=null;
    assertFalse(mMyFragmentPresenter.isValid(value));
}

但它返回以下异常，

java.lang.RuntimeException: android.text.TextUtils 中的方法 isEmpty没有被嘲笑.有关详细信息，请参阅 http://g.co/androidstudio/not-mocked.在android.text.TextUtils.isEmpty(TextUtils.java) at ....

java.lang.RuntimeException: Method isEmpty in android.text.TextUtils not mocked. See http://g.co/androidstudio/not-mocked for details. at android.text.TextUtils.isEmpty(TextUtils.java) at ....

推荐答案

由于JUnit TestCase类不能使用Android相关的API，我们不得不Mock它.
使用 PowerMockito 模拟静态类.

Because of JUnit TestCase class cannot use Android related APIs, we have to Mock it.
Use PowerMockito to Mock the static class.

在您的测试用例类上方添加两行，

Add two lines above your test case class,

@RunWith(PowerMockRunner.class)
@PrepareForTest(TextUtils.class)
public class YourTest
{

}

还有设置代码

@Before
public void setup() {
    PowerMockito.mockStatic(TextUtils.class);
    PowerMockito.when(TextUtils.isEmpty(any(CharSequence.class))).thenAnswer(new Answer<Boolean>() {
        @Override
        public Boolean answer(InvocationOnMock invocation) throws Throwable {
            CharSequence a = (CharSequence) invocation.getArguments()[0];
            return !(a != null && a.length() > 0);
        }
    });
}

用我们自己的逻辑实现 TextUtils.isEmpty().

That implement TextUtils.isEmpty() with our own logic.

另外，在 app.gradle 文件中添加依赖项.

Also, add dependencies in app.gradle files.

testCompile "org.powermock:powermock-module-junit4:1.6.2"
testCompile "org.powermock:powermock-module-junit4-rule:1.6.2"
testCompile "org.powermock:powermock-api-mockito:1.6.2"
testCompile "org.powermock:powermock-classloading-xstream:1.6.2"

感谢 Behelit 和 Exception 的回答.

Thanks Behelit's and Exception's answer.

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