Yes we can test WCMUsePojo using AEM Mocks. To Mock the get methods of WCMUsePojo you need to mock the Bindings. Take a look of below sample class.
public class SampleTest {
@Rule
public AemContext aemContext = new AemContext();
Sample obj = new Sample();
Resource resource = mock(Resource.class);
SlingHttpServletRequest request = mock(SlingHttpServletRequest.class);
Bindings bindings = mock(Bindings.class);
@Before
public void setUp() throws Exception {
aemContext.load().json("/json-import-samples/content.json", "/content/sih");
when(bindings.get("request")).thenReturn(request);
when(request.getResourceResolver()).thenReturn(aemContext.resourceResolver());
when(bindings.get("inheritedPageProperties")).thenReturn(aemContext.resourceResolver().getResource("/content/sih/en/jcr:content").getValueMap());
when(bindings.get("properties")).thenReturn(aemContext.resourceResolver().getResource("/content/sih/en/jcr:content/header/topheader").getValueMap());
}
@Test
//Write test method
}