Android提供商测试

Question

我正在尝试测试Android内容提供商。我正在编写类似于此处给出的代码，插入数据库然后查询数据库， 但有时而且并非总是如此，返回的游标有0行。可能是什么问题？

public class MyProviderTestCase extends ProviderTestCase2<MyProvider> {

private MockContentResolver mMockResolver;
    ....
public MyProviderTestCase() {
    super(MyProvider.class, "com.example.MyProvider");
}

protected void setUp() throws Exception {
    super.setUp();
    mMockResolver = getMockContentResolver();
}

protected void tearDown() throws Exception {
    super.tearDown();
}

@SmallTest
public void testInsertAndUpdate() {
    ...
    SomeObject someObject = ...;
    Uri insertedUri = mMockResolver.insert(MyrProvider.URI, someObject.createContentValues());

    assertNotNull(insertedUri);
    Log.d("test insert and update and delete:inserteduri", insertedUri+"");

    Cursor c = mMockResolver.query(MyProvider.URI, null, null, null, null);
    assertNotNull(c);

    assertTrue(c.moveToFirst());// This assertion fails sometimes
}

}