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Testing PSSH Atom Construction and Validation in SmartTube

This test suite validates the functionality of PsshAtomUtil in ExoPlayer’s MP4 extractor, focusing on PSSH (Protection System Specific Header) atom construction and parsing. The tests ensure proper handling of DRM-related data structures used in protected media content.

Test Coverage Overview

The test suite provides coverage for PSSH atom construction and validation in ExoPlayer’s MP4 processing pipeline.

Key areas tested include:

PSSH atom structure generation
Widevine DRM system ID handling
Scheme data packaging
Atom length and type verification
Version and flags parsing

Implementation Analysis

The testing approach employs JUnit with AndroidJUnit4 runner for Android-specific test execution. The implementation uses byte-level verification to ensure correct PSSH atom construction, with explicit validation of each atom component including length, type, version, flags, and system ID.

The tests utilize ParsableByteArray for precise byte manipulation and Truth assertions for verification.

Technical Details

Testing infrastructure includes:

JUnit test framework with AndroidJUnit4 runner
Google Truth assertion library
ParsableByteArray for byte manipulation
ExoPlayer’s C.WIDEVINE_UUID constant
Custom atom parsing utilities

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Atomic test methods with single responsibility
Comprehensive verification of binary data structures
Clear test method naming conventions
Proper use of assertion libraries
Efficient test data generation

yuliskov/smarttube

exoplayer-amzn-2.10.6/library/core/src/test/java/com/google/android/exoplayer2/extractor/mp4/PsshAtomUtilTest.java

            
/*
 * Copyright (C) 2017 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.mp4;

import static com.google.android.exoplayer2.C.WIDEVINE_UUID;
import static com.google.android.exoplayer2.extractor.mp4.Atom.TYPE_pssh;
import static com.google.android.exoplayer2.extractor.mp4.Atom.parseFullAtomFlags;
import static com.google.android.exoplayer2.extractor.mp4.Atom.parseFullAtomVersion;
import static com.google.common.truth.Truth.assertThat;

import androidx.test.ext.junit.runners.AndroidJUnit4;
import com.google.android.exoplayer2.C;
import com.google.android.exoplayer2.util.ParsableByteArray;
import java.util.UUID;
import org.junit.Test;
import org.junit.runner.RunWith;

/** Tests for {@link PsshAtomUtil}. */
@RunWith(AndroidJUnit4.class)
public final class PsshAtomUtilTest {

  @Test
  public void testBuildPsshAtom() {
    byte[] schemeData = new byte[]{0, 1, 2, 3, 4, 5};
    byte[] psshAtom = PsshAtomUtil.buildPsshAtom(C.WIDEVINE_UUID, schemeData);
    // Read the PSSH atom back and assert its content is as expected.
    ParsableByteArray parsablePsshAtom = new ParsableByteArray(psshAtom);
    assertThat(parsablePsshAtom.readUnsignedIntToInt()).isEqualTo(psshAtom.length); // length
    assertThat(parsablePsshAtom.readInt()).isEqualTo(TYPE_pssh); // type
    int fullAtomInt = parsablePsshAtom.readInt(); // version + flags
    assertThat(parseFullAtomVersion(fullAtomInt)).isEqualTo(0);
    assertThat(parseFullAtomFlags(fullAtomInt)).isEqualTo(0);
    UUID systemId = new UUID(parsablePsshAtom.readLong(), parsablePsshAtom.readLong());
    assertThat(systemId).isEqualTo(WIDEVINE_UUID);
    assertThat(parsablePsshAtom.readUnsignedIntToInt()).isEqualTo(schemeData.length);
    byte[] psshSchemeData = new byte[schemeData.length];
    parsablePsshAtom.readBytes(psshSchemeData, 0, schemeData.length);
    assertThat(psshSchemeData).isEqualTo(schemeData);
  }

}