Need help to write a unit test using Mockito and JUnit4

Question

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

public class MyFragmentPresenterImpl { 
      public Boolean isValid(String value         


        

Answer 1

This is a known issue as mentioned by @Exception. In my case, I also stumbled upon same situation but on advice of senior dev decided to use Strings.isNullOrEmpty() instead of TextUtils.isEmpty(). It turned out to be a nice way to avoid it.

Update: I should better mention it that this utility function Strings.isNullOrEmpty() requires Guava library.

Answer 2

You should use Robolectric:

testImplementation "org.robolectric:robolectric:3.4.2"

And then

@RunWith(RobolectricTestRunner::class)
class TestClass {
    ...
}

Answer 3

As a followup to Johnny's answer, to catch TextUtils.isEmpty(null) calls as well, you could use this piece of code.

PowerMockito.mockStatic(TextUtils.class);
PowerMockito.when(TextUtils.isEmpty(any()))
    .thenAnswer((Answer<Boolean>) invocation -> {
        Object s = invocation.getArguments()[0];
        return s == null || s.length() == 0;
    });

Answer 4

Use PowerMockito

Add this above your class name, and include any other CUT class names (classes under test)

@RunWith(PowerMockRunner.class)
@PrepareForTest({TextUtils.class})
public class ContactUtilsTest
{

Add this to your @Before

@Before
public void setup(){
    PowerMockito.mockStatic(TextUtils.class);
    mMyFragmentPresenter=new MyFragmentPresenterImpl();
}

This will make PowerMockito return default values for methods within TextUtils

You would also have to add the relevant gradle depedencies

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"