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Testing VorbisBitArray Operations in SmartTube ExoPlayer Integration

This test suite validates the VorbisBitArray class functionality in ExoPlayer’s OGG extractor, focusing on bit-level operations and data manipulation for Vorbis audio processing. The tests ensure accurate bit reading, position tracking, and boundary handling.

Test Coverage Overview

The test suite provides comprehensive coverage of VorbisBitArray operations:

Bit-level reading and manipulation testing
Position tracking and management verification
32-bit integer reading capabilities
Boundary condition handling for bit operations
Edge cases for bit skipping and position setting

Implementation Analysis

The testing approach employs JUnit with AndroidJUnit4 runner, utilizing systematic verification of bit operations.

Key patterns include:

Byte array initialization using TestUtil
Sequential bit operation verification
Position tracking validation
Boundary condition testing

Technical Details

Testing infrastructure includes:

JUnit test framework
AndroidJUnit4 test runner
Google Truth assertion library
TestUtil for byte array creation
Custom VorbisBitArray implementation testing

Best Practices Demonstrated

The test suite exemplifies strong testing practices:

Granular test methods for specific functionality
Comprehensive edge case coverage
Clear test method naming
Systematic bit-level validation
Effective use of assertion libraries

yuliskov/smarttube

exoplayer-amzn-2.10.6/library/core/src/test/java/com/google/android/exoplayer2/extractor/ogg/VorbisBitArrayTest.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.exoplayer2.extractor.ogg;

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

import androidx.test.ext.junit.runners.AndroidJUnit4;
import com.google.android.exoplayer2.testutil.TestUtil;
import org.junit.Test;
import org.junit.runner.RunWith;

/** Unit test for {@link VorbisBitArray}. */
@RunWith(AndroidJUnit4.class)
public final class VorbisBitArrayTest {

  @Test
  public void testReadBit() {
    VorbisBitArray bitArray = new VorbisBitArray(TestUtil.createByteArray(0x5c, 0x50));
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.readBit()).isFalse();
  }

  @Test
  public void testSkipBits() {
    VorbisBitArray bitArray = new VorbisBitArray(TestUtil.createByteArray(0xF0, 0x0F));
    bitArray.skipBits(10);
    assertThat(bitArray.getPosition()).isEqualTo(10);
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.readBit()).isFalse();
    bitArray.skipBits(1);
    assertThat(bitArray.getPosition()).isEqualTo(14);
    assertThat(bitArray.readBit()).isFalse();
    assertThat(bitArray.readBit()).isFalse();
  }

  @Test
  public void testGetPosition() throws Exception {
    VorbisBitArray bitArray = new VorbisBitArray(TestUtil.createByteArray(0xF0, 0x0F));
    assertThat(bitArray.getPosition()).isEqualTo(0);
    bitArray.readBit();
    assertThat(bitArray.getPosition()).isEqualTo(1);
    bitArray.readBit();
    bitArray.readBit();
    bitArray.skipBits(4);
    assertThat(bitArray.getPosition()).isEqualTo(7);
  }

  @Test
  public void testSetPosition() throws Exception {
    VorbisBitArray bitArray = new VorbisBitArray(TestUtil.createByteArray(0xF0, 0x0F));
    assertThat(bitArray.getPosition()).isEqualTo(0);
    bitArray.setPosition(4);
    assertThat(bitArray.getPosition()).isEqualTo(4);
    bitArray.setPosition(15);
    assertThat(bitArray.readBit()).isFalse();
  }

  @Test
  public void testReadInt32() {
    VorbisBitArray bitArray = new VorbisBitArray(TestUtil.createByteArray(0xF0, 0x0F, 0xF0, 0x0F));
    assertThat(bitArray.readBits(32)).isEqualTo(0x0FF00FF0);
    bitArray = new VorbisBitArray(TestUtil.createByteArray(0x0F, 0xF0, 0x0F, 0xF0));
    assertThat(bitArray.readBits(32)).isEqualTo(0xF00FF00F);
  }

  @Test
  public void testReadBits() throws Exception {
    VorbisBitArray bitArray = new VorbisBitArray(TestUtil.createByteArray(0x03, 0x22));
    assertThat(bitArray.readBits(2)).isEqualTo(3);
    bitArray.skipBits(6);
    assertThat(bitArray.readBits(2)).isEqualTo(2);
    bitArray.skipBits(2);
    assertThat(bitArray.readBits(2)).isEqualTo(2);
    bitArray.reset();
    assertThat(bitArray.readBits(16)).isEqualTo(0x2203);
  }

  @Test
  public void testRead4BitsBeyondBoundary() throws Exception {
    VorbisBitArray bitArray = new VorbisBitArray(TestUtil.createByteArray(0x2e, 0x10));
    assertThat(bitArray.readBits(7)).isEqualTo(0x2e);
    assertThat(bitArray.getPosition()).isEqualTo(7);
    assertThat(bitArray.readBits(4)).isEqualTo(0x0);
  }

  @Test
  public void testReadBitsBeyondByteBoundaries() throws Exception {
    VorbisBitArray bitArray = new VorbisBitArray(TestUtil.createByteArray(0xFF, 0x0F, 0xFF, 0x0F));
    assertThat(bitArray.readBits(32)).isEqualTo(0x0FFF0FFF);

    bitArray.reset();
    bitArray.skipBits(4);
    assertThat(bitArray.readBits(16)).isEqualTo(0xF0FF);

    bitArray.reset();
    bitArray.skipBits(6);
    assertThat(bitArray.readBits(12)).isEqualTo(0xc3F);

    bitArray.reset();
    bitArray.skipBits(6);
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.readBit()).isTrue();
    assertThat(bitArray.bitsLeft()).isEqualTo(24);

    bitArray.reset();
    bitArray.skipBits(10);
    assertThat(bitArray.readBits(5)).isEqualTo(3);
    assertThat(bitArray.getPosition()).isEqualTo(15);
  }

  @Test
  public void testReadBitsIllegalLengths() throws Exception {
    VorbisBitArray bitArray = new VorbisBitArray(TestUtil.createByteArray(0x03, 0x22, 0x30));

    // reading zero bits gets 0 without advancing position
    // (like a zero-bit read is defined to yield zer0)
    assertThat(bitArray.readBits(0)).isEqualTo(0);
    assertThat(bitArray.getPosition()).isEqualTo(0);
    bitArray.readBit();
    assertThat(bitArray.getPosition()).isEqualTo(1);
  }

}