android - findFragmentByTag的单元测试条件

Android Studio 3.2 Canary 2
Build #AI-173.4591728, built on February 8, 2018
JRE: 1.8.0_152-release-1024-b01 amd64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Linux 4.14.18-300.fc27.x86_64

我有以下 Activity ，我想对 fragment 已连接的情况进行单元测试，并应返回非null值。并且应该落入else条件:

这是我的 Activity :

public class BillingActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.billing_container);

        if(getSupportFragmentManager().findFragmentByTag(BillingView.TAG) == null) {
            final FragmentTransaction fragmentTransaction =
                    getSupportFragmentManager().beginTransaction();

            fragmentTransaction.add(
                    R.id.billing_view_container,
                    BillingView.newInstance(),
                    BillingView.TAG);

            fragmentTransaction.commit();
        }
        else {
            Timber.d("Fragment already attached");
        }
    }
}

测试类是这样的:我可以编写测试来附加一个 fragment ，但是当 fragment 已经附加并且应该返回非null时，我想测试条件。

class BillingActivityTest: BaseRobolectricTestRunner() {
    private lateinit var billingActivity: BillingActivity

    @Before
    fun setup() {
        billingActivity = Robolectric.buildActivity(BillingActivity::class.java)
                .create()
                .start()
                .get()
    }

    @Test
    fun testBillingActivityIsNotNullValue() {
        assertThat(billingActivity, `is`(notNullValue()))
    }

    @Test
    fun testBillingFragmentHasStarted() {
        val actualFragment = billingActivity
                .supportFragmentManager
                .findFragmentByTag(BillingView.TAG)

        assertThat(actualFragment.tag, `is`(BillingView.TAG))
    }

    @Test
    fun testBillingFragmentAlreadyAttached() {
        /* how to test */
    }
}

感谢您的任何建议，

最佳答案

只要方法you've chosen(使用 recreate() )能够复制您所请求的行为，它将起作用。我相信这是目前为止最短的方法。

但是，我不能将其视为纯粹的单元测试，因为实际上您在作弊，因为显然您对 Activity 的recreate()操作不感兴趣(这也可能会有副作用)。

如果您要执行纯单元测试，那么这里是这样做的方法。宣布 Activity 为:
class MainActivity : AppCompatActivity() { internal var fragmentManagerRetriever = FragmentManagerRetriever() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) val fragmentManager = fragmentManagerRetriever.getFragmentManager(this) if (fragmentManager.findFragmentByTag("TAG") == null) { val fragmentTransaction = fragmentManager.beginTransaction() fragmentTransaction.add(SomeFragment(), "TAG") fragmentTransaction.commit() } } }FragmentManagerRetriever就是这样简单:
class FragmentManagerRetriever { public FragmentManager getFragmentManager(FragmentActivity activity) { return activity.getSupportFragmentManager(); } }
然后，您就可以执行纯单元测试了:
@Test fun nullCase() { val activityController = Robolectric.buildActivity(MainActivity::class.java) val activity = activityController.get() val fragmentManagerRetriever = mock(FragmentManagerRetriever::class.java) val fragmentManager = mock(FragmentManager::class.java) val fragmentTransaction = mock(FragmentTransaction::class.java) activity.fragmentManagerRetriever = fragmentManagerRetriever `when`(fragmentManagerRetriever.getFragmentManager(activity)).thenReturn(fragmentManager) `when`(fragmentManager.findFragmentByTag("TAG")).thenReturn(null) `when`(fragmentManager.beginTransaction()).thenReturn(fragmentTransaction) activityController.create() val inOrder = Mockito.inOrder(fragmentTransaction) inOrder.verify(fragmentTransaction).add(ArgumentMatchers.any(SomeFragment::class.java), ArgumentMatchers.eq("TAG")) inOrder.verify(fragmentTransaction).commit() }
并测试非空的情况:
@Test fun nonNullCase() { val activityController = Robolectric.buildActivity(MainActivity::class.java) val activity = activityController.get() val fragmentManagerRetriever = mock(FragmentManagerRetriever::class.java) val fragmentManager = mock(FragmentManager::class.java) val fragmentTransaction = mock(FragmentTransaction::class.java) activity.fragmentManagerRetriever = fragmentManagerRetriever `when`(fragmentManagerRetriever.getFragmentManager(activity)).thenReturn(fragmentManager) `when`(fragmentManager.findFragmentByTag("TAG")).thenReturn(mock(Fragment::class.java)) activityController.create() verifyZeroInteractions(fragmentTransaction) }

关于android - findFragmentByTag的单元测试条件，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/48812927/