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Testing ClearKey DRM Data Adjustments in SmartTube

This test suite validates the ClearKeyUtil class functionality in ExoPlayer’s DRM implementation, focusing on request and response data adjustments across different Android SDK versions. The tests ensure proper handling of key formats and character replacements for DRM operations.

Test Coverage Overview

The test suite provides comprehensive coverage of ClearKeyUtil’s data adjustment functionality:

Single key response data adjustments for SDK 26
Multi-key response data handling
Request data modifications for different SDK versions
Character replacement validation for DRM keys

Implementation Analysis

The testing approach utilizes JUnit4 with AndroidJUnit4 runner and Robolectric for Android environment simulation. Tests are structured to verify both SDK version 26 and 27 behaviors, using @Config annotations to control the test environment.

Key patterns include byte array comparisons and JSON string manipulation verification.

Technical Details

Testing tools and configuration:

JUnit4 test framework
Robolectric for Android SDK simulation
Truth assertion library for precise comparisons
SDK version-specific configurations (@Config annotations)
UTF-8 byte array handling utilities

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Clear test method naming conventions
Isolated test cases for different scenarios
Comprehensive SDK version coverage
Well-defined test data constants
Proper assertion usage with descriptive messages

yuliskov/smarttube

exoplayer-amzn-2.10.6/library/core/src/test/java/com/google/android/exoplayer2/drm/ClearKeyUtilTest.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.drm;

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

import androidx.test.ext.junit.runners.AndroidJUnit4;
import com.google.android.exoplayer2.util.Util;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.robolectric.annotation.Config;

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

  private static final byte[] SINGLE_KEY_RESPONSE =
      Util.getUtf8Bytes(
          "{"
              + "\"keys\":["
              + "{"
              + "\"k\":\"abc_def-\","
              + "\"kid\":\"ab_cde-f\","
              + "\"kty\":\"o_c-t\","
              + "\"ignored\":\"ignored\""
              + "}"
              + "],"
              + "\"ignored\":\"ignored\""
              + "}");
  private static final byte[] MULTI_KEY_RESPONSE =
      Util.getUtf8Bytes(
          "{"
              + "\"keys\":["
              + "{"
              + "\"k\":\"abc_def-\","
              + "\"kid\":\"ab_cde-f\","
              + "\"kty\":\"oct\","
              + "\"ignored\":\"ignored\""
              + "},{"
              + "\"k\":\"ghi_jkl-\","
              + "\"kid\":\"gh_ijk-l\","
              + "\"kty\":\"oct\""
              + "}"
              + "],"
              + "\"ignored\":\"ignored\""
              + "}");
  private static final byte[] KEY_REQUEST =
      Util.getUtf8Bytes(
          "{"
              + "\"kids\":["
              + "\"abc+def/\","
              + "\"ab+cde/f\""
              + "],"
              + "\"type\":\"temporary\""
              + "}");

  @Config(sdk = 26)
  @Test
  public void testAdjustSingleKeyResponseDataV26() {
    // Everything but the keys should be removed. Within each key only the k, kid and kty parameters
    // should remain. Any "-" and "_" characters in the k and kid values should be replaced with "+"
    // and "/".
    byte[] expected =
        Util.getUtf8Bytes(
            "{"
                + "\"keys\":["
                + "{"
                + "\"k\":\"abc/def+\",\"kid\":\"ab/cde+f\",\"kty\":\"o_c-t\""
                + "}"
                + "]"
                + "}");
    assertThat(ClearKeyUtil.adjustResponseData(SINGLE_KEY_RESPONSE)).isEqualTo(expected);
  }

  @Config(sdk = 26)
  @Test
  public void testAdjustMultiKeyResponseDataV26() {
    // Everything but the keys should be removed. Within each key only the k, kid and kty parameters
    // should remain. Any "-" and "_" characters in the k and kid values should be replaced with "+"
    // and "/".
    byte[] expected =
        Util.getUtf8Bytes(
            "{"
                + "\"keys\":["
                + "{"
                + "\"k\":\"abc/def+\",\"kid\":\"ab/cde+f\",\"kty\":\"oct\""
                + "},{"
                + "\"k\":\"ghi/jkl+\",\"kid\":\"gh/ijk+l\",\"kty\":\"oct\""
                + "}"
                + "]"
                + "}");
    assertThat(ClearKeyUtil.adjustResponseData(MULTI_KEY_RESPONSE)).isEqualTo(expected);
  }

  @Config(sdk = 27)
  @Test
  public void testAdjustResponseDataV27() {
    // Response should be unchanged.
    assertThat(ClearKeyUtil.adjustResponseData(SINGLE_KEY_RESPONSE)).isEqualTo(SINGLE_KEY_RESPONSE);
  }

  @Config(sdk = 26)
  @Test
  public void testAdjustRequestDataV26() {
    // We expect "+" and "/" to be replaced with "-" and "_" respectively, for "kids".
    byte[] expected =
        Util.getUtf8Bytes(
            "{"
                + "\"kids\":["
                + "\"abc-def_\","
                + "\"ab-cde_f\""
                + "],"
                + "\"type\":\"temporary\""
                + "}");
    assertThat(ClearKeyUtil.adjustRequestData(KEY_REQUEST)).isEqualTo(expected);
  }

  @Config(sdk = 27)
  @Test
  public void testAdjustRequestDataV27() {
    // Request should be unchanged.
    assertThat(ClearKeyUtil.adjustRequestData(KEY_REQUEST)).isEqualTo(KEY_REQUEST);
  }

}