如何对LiveData转换进行单元测试

import androidx.arch.core.executor.testing.InstantTaskExecutorRule;
import androidx.lifecycle.LiveData;
import androidx.lifecycle.Observer;
import androidx.lifecycle.Transformations;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;

@RunWith(MockitoJUnitRunner.class)
public class LiveDataTransformationTest {

    @Rule
    public InstantTaskExecutorRule instantTaskExecutorRule = new InstantTaskExecutorRule();

    private LiveData<Integer> sourceLiveData;
    private LiveData<String> transformedLiveData;

    @Mock
    private Observer<String> observer;

    @Before
    public void setup() {
        sourceLiveData = new LiveData<>();
        transformedLiveData = Transformations.map(sourceLiveData, input -> "Transformed: " + input);
        transformedLiveData.observeForever(observer);
    }

    @Test
    public void testLiveDataTransformation() {
        sourceLiveData.setValue(10);
        Assert.assertEquals("Transformed: 10", transformedLiveData.getValue());
    }
}