嗨我建立一个简单的RecycleView适配器,我试图测试适配器的所有方法,但onCreateViewHolder对我来说是困难的.
@Override
public NewsViewHolder onCreateViewHolder(ViewGroup parent,int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.fragment_news,parent,false);
return new NewsViewHolder(v);
}
我尝试使用mockito构建一个viewGroup类的模拟,并在调用getContext()时返回MockContext的间谍,但似乎是因为我返回一个MockContext,LayoutInflater.from()返回一个空指针异常.
这是我的考验
@Test
public void testOnCreateViewHolder() throws Exception {
ViewGroup vg = mock(ViewGroup.class);
MockContext mockContext = new MockContext();
MockContext spyContext = spy(mockContext);
when(vg.getContext()).thenReturn(spyContext);
NewsViewHolder vh = adapter.onCreateViewHolder(vg,0);
Assert.assertNotNull("Response cant be null",vh);
}
提前致谢.
解决方法
当我遇到同样的问题时,我遇到了这个问题.我最终自己解决了这个问题.
假设您有一个简单的onCreateViewHolder,如下所示：
@Override
public TeamsViewHolder onCreateViewHolder(ViewGroup parent,int viewType) {
return new NewsViewHolder(LayoutInflater
.from(parent.getContext())
.inflate(R.layout.fragment_news_view_holder,false)
);
}
使用PowerMock模拟LayoutInflater的静态实例.在下面的代码段中,我使用编号注释注释了为使这项工作需要采取的所有步骤：
import android.test.mock.MockContext;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.powermockrunner;
import static junit.framework.Assert.assertEquals;
import static junit.framework.Assert.assertNotNull;
import static org.mockito.Matchers.anyInt;
import static org.mockito.Matchers.eq;
import static org.mockito.Mockito.when;
import static org.powermock.api.mockito.powermockito.mockStatic;
// 1. signal JUnit to run this test powermockrunner
@RunWith(powermockrunner.class)
// 2. signal PowerMock to prepare the static instance of LayoutInflater for testing
@PrepareForTest({LayoutInflater.class})
public class NewsRecyclerViewAdapterTest {
// 3. LayoutInflater.from(context) returns an inflater,// so we need to mock that one
@Mock
LayoutInflater mockInflater;
@Mock
View mockView;
@Mock
ViewGroup mockParent;
private int dummyTestId;
private MockContext mockContext;
private NewsRecyclerViewAdapter adapter;
@Before
public void setUp() throws Exception {
MockitoAnnotations.initMocks(this);
dummyTestId = 0x10000;
// 4. mock the static LayoutInflater in "LayoutInflater.from()"
// so that we can ask it to return a mockInflater that we moked above
mockStatic(LayoutInflater.class);
mockContext = new MockContext();
adapter = new NewsRecyclerViewAdapter(Arrays.asList(new NewsItem(),new NewsItem(),new NewsItem()));
}
@Test
public void onCreateViewHolderShouldReturnAValidViewHolder() throws Exception {
// 5. mock the context that comes from parent ViewGroup
when(mockParent.getContext()).thenReturn(mockContext);
// 6. mock the inflater that is returned by LayoutInflater.from()
when(LayoutInflater.from(mockContext)).thenReturn(mockInflater);
// 7. pass anyInt() as a resource id to care of R.layout.fragment_news_view_holder in onCreateViewHolder()
when(mockInflater.inflate(anyInt(),eq(mockParent),eq(false))).thenReturn(mockView);
// call onCreateViewHolder() to act
NewsViewHolder viewHolder = adapter.onCreateViewHolder(mockParent,dummyTestId);
// OKAY straightfoward right?
assertNotNull(viewHolder);
// this is not very important but I recommend it,// it just returns the view sent to NewsViewHolder
// and verify it against the mockView that you inflated above
assertEquals(viewHolder.getItemView(),mockView);
}
}