car-ui-lib/car-ui-lib/src/androidTest/java/com/android/car/ui/recyclerview/ContentLimitingAdapterTest.java

/*
 * Copyright (C) 2020 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.car.ui.recyclerview;

import static com.google.common.truth.Truth.assertThat;

import android.widget.LinearLayout;

import androidx.recyclerview.widget.RecyclerView;
import androidx.test.rule.ActivityTestRule;

import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;

public class ContentLimitingAdapterTest {

    @Rule
    public ActivityTestRule<CarUiRecyclerViewTestActivity> mActivityRule =
            new ActivityTestRule<>(CarUiRecyclerViewTestActivity.class);

    private ContentLimitingAdapter<TestViewHolder> mContentLimitingAdapter;

    @Before
    public void setUp() {
        mContentLimitingAdapter = new TestContentLimitingAdapter(50);
    }

    @Test
    public void setMaxItem_toLowerThanTotalItems() {
        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(50);
        RecyclerView.ViewHolder last = getItemAtPosition(49);
        isTestViewHolderWithText(last, "Item 49");

        // Switch to limited
        mContentLimitingAdapter.setMaxItems(20);

        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(21);
        RecyclerView.ViewHolder secondToLast = getItemAtPosition(19);
        isTestViewHolderWithText(secondToLast, "Item 19");

        last = getItemAtPosition(20);
        assertThat(last).isInstanceOf(ScrollingLimitedViewHolder.class);

        // Switch back to unlimited
        mContentLimitingAdapter.setMaxItems(-1);

        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(50);
        last = getItemAtPosition(49);
        isTestViewHolderWithText(last, "Item 49");
    }

    @Test
    public void setMaxItem_toOne() {
        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(50);
        RecyclerView.ViewHolder last = getItemAtPosition(49);
        isTestViewHolderWithText(last, "Item 49");

        mContentLimitingAdapter.setMaxItems(1);

        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(2);
        RecyclerView.ViewHolder secondToLast = getItemAtPosition(0);
        isTestViewHolderWithText(secondToLast, "Item 0");

        last = getItemAtPosition(1);
        assertThat(last).isInstanceOf(ScrollingLimitedViewHolder.class);

        // Switch back to unlimited
        mContentLimitingAdapter.setMaxItems(-1);

        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(50);
        last = getItemAtPosition(49);
        isTestViewHolderWithText(last, "Item 49");
    }

    @Test
    public void setMaxItem_toZero() {
        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(50);
        RecyclerView.ViewHolder last = getItemAtPosition(49);
        isTestViewHolderWithText(last, "Item 49");

        mContentLimitingAdapter.setMaxItems(0);

        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(1);
        last = getItemAtPosition(0);
        assertThat(last).isInstanceOf(ScrollingLimitedViewHolder.class);

        // Switch back to unlimited
        mContentLimitingAdapter.setMaxItems(-1);

        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(50);
        last = getItemAtPosition(49);
        isTestViewHolderWithText(last, "Item 49");
    }

    @Test
    public void setMaxItem_toHigherThanTotalItems() {
        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(50);
        RecyclerView.ViewHolder last = getItemAtPosition(49);
        isTestViewHolderWithText(last, "Item 49");

        mContentLimitingAdapter.setMaxItems(70);

        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(50);
        RecyclerView.ViewHolder secondToLast = getItemAtPosition(48);
        isTestViewHolderWithText(secondToLast, "Item 48");

        last = getItemAtPosition(49);
        isTestViewHolderWithText(last, "Item 49");

        // Switch back to unlimited
        mContentLimitingAdapter.setMaxItems(-1);

        assertThat(mContentLimitingAdapter.getItemCount()).isEqualTo(50);
        last = getItemAtPosition(49);
        isTestViewHolderWithText(last, "Item 49");
    }

    private RecyclerView.ViewHolder getItemAtPosition(int position) {
        int viewType = mContentLimitingAdapter.getItemViewType(position);
        RecyclerView.ViewHolder viewHolder =
                mContentLimitingAdapter.createViewHolder(
                        new LinearLayout(mActivityRule.getActivity().getApplicationContext()),
                        viewType);
        mContentLimitingAdapter.bindViewHolder(viewHolder, position);
        return viewHolder;
    }

    private void isTestViewHolderWithText(RecyclerView.ViewHolder secondToLast, String s) {
        assertThat(secondToLast).isInstanceOf(TestViewHolder.class);
        TestViewHolder testViewHolder = (TestViewHolder) secondToLast;
        assertThat(testViewHolder.getText()).isEqualTo(s);
    }
}