com/android/setupwizardlib/test/BottomScrollViewTest.java

/*
 * Copyright (C) 2015 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.android.setupwizardlib.test;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

import android.content.Context;
import android.view.View;
import android.support.test.InstrumentationRegistry;
import android.support.test.filters.SmallTest;
import android.support.test.runner.AndroidJUnit4;
import com.android.setupwizardlib.view.BottomScrollView;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(AndroidJUnit4.class)
@SmallTest
public class BottomScrollViewTest {

  private TestBottomScrollListener mListener;

  @Before
  public void setUp() throws Exception {
    mListener = new TestBottomScrollListener();
  }

  @Test
  public void testNoNeedScroll() {
    createScrollView(20);
    assertTrue("Scroll should not be required", mListener.mScrolledToBottom);
  }

  @Test
  public void testNeedScroll() {
    createScrollView(110);
    assertFalse("Scroll should be required", mListener.mScrolledToBottom);
  }

  @Test
  public void testScrollToBottom() {
    final BottomScrollView bottomScrollView = createScrollView(110);

    assertFalse("Scroll should be required", mListener.mScrolledToBottom);

    bottomScrollView.scrollTo(0, 10);
    assertTrue("Should already be scrolled to bottom", mListener.mScrolledToBottom);
  }

  @Test
  public void testScrollThreshold() {
    final BottomScrollView bottomScrollView = createScrollView(110);
    assertEquals("Scroll threshold should be 10", 10, bottomScrollView.getScrollThreshold());
  }

  private BottomScrollView createScrollView(final int childHeight) {
    final Context context = InstrumentationRegistry.getContext();
    final BottomScrollView bottomScrollView = new TestBottomScrollView(context);
    bottomScrollView.setBottomScrollListener(mListener);

    final View child = new TestChildView(context, childHeight);

    child.measure(0, 0); // TestChildView's measured dimensions doesn't depend on the arguments
    bottomScrollView.addView(child);
    bottomScrollView.layout(0, 0, 100, 100);

    return bottomScrollView;
  }

  private static class TestChildView extends View {

    private static final int WIDTH = 10;
    private int mHeight;

    TestChildView(Context context, int height) {
      super(context);
      mHeight = height;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
      setMeasuredDimension(WIDTH, mHeight);
    }

    public void setHeight(int height) {
      mHeight = height;
    }
  }

  private static class TestBottomScrollView extends BottomScrollView {

    TestBottomScrollView(Context context) {
      super(context);
    }

    @Override
    public boolean post(Runnable action) {
      // Post all runnables synchronously so that tests can check the callbacks.
      action.run();
      return true;
    }
  }

  private static class TestBottomScrollListener implements BottomScrollView.BottomScrollListener {

    boolean mScrolledToBottom = true;

    @Override
    public void onScrolledToBottom() {
      mScrolledToBottom = true;
    }

    @Override
    public void onRequiresScroll() {
      mScrolledToBottom = false;
    }
  }
}