我的JUnit测试删除操作是否正确？

Question

I want to write JUnit test for delete operation that call delete method ORMLite library (it is not important). I'm mocking behaviour of ORMLite API in my tests. But I'm not sure that I created the correct test and that I'm really testing delete operation.

So, I have defined some datasource class with operations create(List<Object> o), read(Object o), delete (Object o) . Here is simplified code.

class ObjectDataSource {

    public void create (List<Object> o) {
        ormapi.create(o);    
    }

    public List<Object> read (Object o ) {
        return ormapi.queryForMatching(o);
    }

    public void delete (Object o) {
        ormapi.delete(o);
    }

}

Now,I here is created JUnit test. It's testing that Object was really removed.

@Test
public void readTest() {
    // ormlite api init
    RuntimeExceptionDao<Object, Integer> dao = mock(RuntimeExceptionDao.class);
    ObjectDbHelper dbHelper = new ObjectDbHelper(context, dao);
    ObjectDataSource dataSource = new ObjectDataSource(context, dbHelper);

    // data init
    Object object = new Object() {{ setId(47); }};
    Object completeObject = new Object {{ setId(47); setObjectName("test object"); }}
    List<Object> list = ArrayList<Object>();
    list.add(completeObject);

    // api mocking
    when(dao.queryForMatching(object)).thenReturn(new ArrayList<Object>());

    // testing
    dataSource.create(list);
    dataSource.delete(object);
    List<Object> readList = dataSource.read(object);
    Assert.assertEquals(new ArrayList<Object>(), readList);
}

Answer 1

You ought to be checking that delete() has been called. You probably need something like:

@Test
public void readTest() {
    // ormlite api init
    RuntimeExceptionDao<Object, Integer> dao = mock(RuntimeExceptionDao.class);
    ObjectDbHelper dbHelper = new ObjectDbHelper(context, dao);
    ObjectDataSource dataSource = new ObjectDataSource(context, dbHelper);

    // data init
    Object object = new Object() {{ setId(47); }};
    Object completeObject = new Object {{ setId(47); setObjectName("test object"); }}
    List<Object> list = ArrayList<Object>();
    list.add(completeObject);

    // testing
    dataSource.create(list);
    dataSource.delete(object);

    // verify that ObjectDataSource class correctly invokes delete
    // method on DAO:
    verify(dao).delete(object);
}

I see no benefit in calling dataSource.read() and testing the result, since you've faked that result with your mocked DAO object. It doesn't really tell you anything. It's like setting int x = 5; and then checking x is 5 .

Also, your test is very misleadingly named if your intention is to check deletion works... Something like deleteTest might be a better name :-)