How to mock a static method inside a factory class - unit-testing

Question

I need to mock the behavior of a static method inside a non-static factory class. The implementation of the class is:
ABCFactory.java
public class ABCFactory extends BaseUserFactory
{
private static final ABCFactory factory = new ABCFactory();
public static final ABCFactory getFactory()
{
return factory;
}
public Context getContext(String authority)
{
return (Context)createInstance(authority);
}
private ABCFactory()
{
}
protected Class getInterface()
{
return ABCFactory.class;
}
}
Now, this class is used in my code to get the profile something like:
Document.java:
Profile profile = ABCFactory.getFactory().getContext(authority).currentProfile();
I need to mock the ABCFactory class so that I can send my own context/profile object as a return type while testing. I've tried a bunch of methods but nothing seems to work here. Here's what I tried in my junit test class.
Try 1:
DocumentTest.java
ABCFactory mockABCFactory = Mockito.mock(ABCFactory.class);
ServiceProviderRegistrar.getRegistrar().bind(ABCFactory.class).toMockInstance(mockABCFactory);
Mockito.when(mockABCFactory .getFactory()).thenReturn(null);
Mockito.when(mockABCFactory .getContext(domain)).thenReturn(null);
Error:
org.mockito.exceptions.misusing.MissingMethodInvocationException:
when() requires an argument which has to be 'a method call on a mock'.
For example:
when(mock.getArticles()).thenReturn(articles);
Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
Those methods cannot be stubbed/verified.
2. inside when() you don't call method on mock but on some other object.
Try 2: (Using PowerMock to avoid the new call.
DocumentTest.java
ABCFactory mockABCFactory = Mockito.mock(ABCFactory.class);
ServiceProviderRegistrar.getRegistrar().bind(ABCFactory.class).toMockInstance(mockABCFactory);
try
{
PowerMockito.whenNew(ABCFactory.class).withNoArguments().thenReturn(mockABCFactory);
PowerMockito.when(ABCFactory.getFactory()).thenReturn(mockABCFactory);
}
catch (Exception e)
{
e.printStackTrace();
}
Mockito.when(mockABCFactory.getContext(domain)).thenReturn(null);
Error:
org.mockito.exceptions.misusing.MissingMethodInvocationException:
when() requires an argument which has to be 'a method call on a mock'.
For example:
when(mock.getArticles()).thenReturn(articles);
Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
Those methods cannot be stubbed/verified.
2. inside when() you don't call method on mock but on some other object.
at org.powermock.api.mockito.PowerMockito.when(PowerMockito.java:490)
Try 3: (Used PowerMock.mockStatic)
DocumentTest.java
ABCFactory mockABCFactory= Mockito.mock(ABCFactory.class);
ServiceProviderRegistrar.getRegistrar().bind(ABCFactory.class).toMockInstance(mockABCFactory);
try
{
PowerMockito.whenNew(ABCFactory.class).withNoArguments().thenReturn(mockABCFactory);
PowerMockito.mockStatic(ABCFactory.class);
PowerMockito.when(ABCFactory.getFactory()).thenReturn(mockABCFactory);
}
catch (Exception e)
{
e.printStackTrace();
}
Mockito.when(mockABCFactory.getContext(domain)).thenReturn(null);
Error:
org.mockito.exceptions.misusing.MissingMethodInvocationException:
when() requires an argument which has to be 'a method call on a mock'.
For example:
when(mock.getArticles()).thenReturn(articles);
Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
Those methods cannot be stubbed/verified.
2. inside when() you don't call method on mock but on some other object.
at org.powermock.api.mockito.PowerMockito.when(PowerMockito.java:490)
What am I missing here. I have tried several other ways but ABCFactory.getFactory() always returns a new object but not my mocked object. How do I mock the behavior of ABCFactory class without changing its implementation?! Please help.

Answer 1

Did you use following annotations.
#RunWith(PowerMockRunner.class)
#PrepareForTest( ABCFactory.class )
I tried and following code works.
DocumentTest.class
#RunWith(PowerMockRunner.class)
#PrepareForTest( ABCFactory.class )
public class DocumentTest
{
/** Unit under test. */
private Document user;
#Before public void setUp() {
user = new Document();
ABCFactory abc = ABCFactory.getFactory();
PowerMockito.mockStatic(ABCFactory.class);
PowerMockito.when(ABCFactory.getFactory()).thenReturn(abc);
}
#Test public void testABC() {
assertEquals("", user.useFactory() );
}
}
Document class
public class Document
{
public String useFactory(){
String profile = ABCFactory.getFactory().getContext("");
return profile;
}
}