Hi I really hope you can help me, I feel like I've been pulling my hair out for days.
I'm trying to write unit tests for a method A. Method A calls a static method B. I want to mock static method B.
I know this has been asked before, but I feel Android has matured since then, and there must be a way to do such a simple task without re-writing the methods I want to test.
Here is an example, first the method I want to test:
public String getUserName(Context context, HelperUtils helper) {
if(helper == null){
helper = new HelperUtils();
}
int currentUserId = helper.fetchUsernameFromInternet(context);
if (currentUserId == 1) {
return "Bob";
} else {
return "Unknown";
}
}
Next the static method I want to mock:
public class HelperUtils {
public static int fetchUsernameFromInternet(Context context) {
int userid = 0;
Log.i("HelperUtils ", "hello");
return userid;
}
}
In other languages this is so easy but I just can't make it work in Android. I've tried Mockito, but it appears static methods aren't supported
HelperUtils helper = Mockito.mock(HelperUtils.class);
Mockito.when(helper.fetchUsernameFromInternet(getContext())).thenReturn(1);
This errors
org.mockito.exceptions.misusing.MissingMethodInvocationException
I've tried Powermock but I'm not completely sure this is supported by Android. I managed to get powermock running using androidCompile in my gradle file but I get this error:
Error:Execution failed for task ':app:dexDebugAndroidTest'. com.android.ide.common.process.ProcessException:
Not to mention PowerMockito.mockStatic(HelperUtils.class);
Doesn't return anything, so I don't know what to pass into my getUsername method!
Any help would be so very much appreciated.
Static methods aren't related to any object - your helper.fetchUsernameFromInternet(...)
is the same (but a bit confusing) as HelperUtils.fetchUsernameFromInternet(...)
- you should even get a compiler warning due to this helper.fetchUsernameFromInternet
.
What's more, instead of Mockito.mock
to mock static methods you have to use: @RunWith(...)
, @PrepareForTest(...)
and then PowerMockito.mockStatic(...)
- complete example is here: PowerMockito mock single static method and return object
In other words - mocking static methods (and also constructors) is a bit tricky. Better solution is:
if you can change HelperUtils
, make that method non-static and now you can mock HelperUtils
with the usual Mockito.mock
if you can't change HelperUtils
, create a wrapper class which delegates to the original HelperUtils
, but doesn't have static
methods, and then also use usual Mockito.mock
(this idea is sometimes called "don't mock types you don't own")