material-components_material-components-android/tests/javatests/com/google/android/material/tabs/TabLayoutPoolingTest.java

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.android.material.tabs;

import static org.junit.Assert.assertTrue;

import android.app.Activity;
import androidx.test.annotation.UiThreadTest;
import androidx.test.filters.SmallTest;
import androidx.test.rule.ActivityTestRule;
import androidx.test.runner.AndroidJUnit4;
import com.google.android.material.testapp.R;
import com.google.android.material.testapp.TabLayoutPoolingActivity;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(AndroidJUnit4.class)
public class TabLayoutPoolingTest {

  @Rule
  public final ActivityTestRule<TabLayoutPoolingActivity> activityTestRule =
      new ActivityTestRule<>(TabLayoutPoolingActivity.class);

  @UiThreadTest
  @SmallTest
  @Test
  public void testUsingTabsFromOtherInstance() {
    final Activity activity = activityTestRule.getActivity();

    // TabLayout1 has items added via the layout, so we'll just check they're
    // there first
    final TabLayout tabLayout1 = activity.findViewById(R.id.tabs_1);
    assertTrue(tabLayout1.getTabCount() > 0);

    // Now remove all tabs. TabLayout will pool the Tab instances...
    tabLayout1.removeAllTabs();

    // Now add some tabs to the second TabLayout and make sure that we don't crash
    final TabLayout tabLayout2 = activity.findViewById(R.id.tabs_2);
    tabLayout2.addTab(tabLayout2.newTab());
    tabLayout2.addTab(tabLayout2.newTab());
    tabLayout2.addTab(tabLayout2.newTab());
  }
}