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Validating ActionFile Operations in SmartTube's ExoPlayer Implementation

This test suite validates the functionality of ActionFile, a core component in ExoPlayer’s offline download system. It focuses on file handling, data integrity, and error conditions when managing download actions.

Test Coverage Overview

The test suite provides comprehensive coverage of ActionFile operations including:

File loading scenarios with valid and invalid data
Action count verification (zero, one, and multiple actions)
Version compatibility checks
Error handling for incomplete/corrupt files

Key edge cases include handling of incomplete headers, unsupported versions, and empty action files.

Implementation Analysis

The testing approach utilizes JUnit4 with AndroidJUnit4 runner for Android-specific context handling. The implementation follows AAA (Arrange-Act-Assert) pattern with setUp/tearDown lifecycle hooks for test isolation.

Notable patterns include temporary file management, test data generation, and expected vs actual comparisons using Truth assertions.

Technical Details

Testing infrastructure includes:

JUnit4 test framework with AndroidJUnit4 runner
Google Truth assertion library
TestUtil for test data generation
ApplicationProvider for Android context access
Temporary file management using ExoPlayer’s Util class

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Proper test isolation through @Before/@After hooks
Comprehensive error case coverage
Clear test method naming conventions
Efficient test resource cleanup
Focused test cases with single responsibility

yuliskov/smarttube

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

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

import android.net.Uri;
import androidx.test.core.app.ApplicationProvider;
import androidx.test.ext.junit.runners.AndroidJUnit4;
import com.google.android.exoplayer2.testutil.TestUtil;
import com.google.android.exoplayer2.util.Util;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Collections;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

/** Unit tests for {@link ActionFile}. */
@SuppressWarnings("deprecation")
@RunWith(AndroidJUnit4.class)
public class ActionFileTest {

  private File tempFile;
  private DownloadRequest expectedAction1;
  private DownloadRequest expectedAction2;

  @Before
  public void setUp() throws Exception {
    tempFile = Util.createTempFile(ApplicationProvider.getApplicationContext(), "ExoPlayerTest");
    expectedAction1 =
        buildExpectedRequest(Uri.parse("http://test1.uri"), TestUtil.buildTestData(16));
    expectedAction2 =
        buildExpectedRequest(Uri.parse("http://test2.uri"), TestUtil.buildTestData(32));
  }

  @After
  public void tearDown() throws Exception {
    tempFile.delete();
  }

  @Test
  public void testLoadNoDataThrowsIOException() throws Exception {
    ActionFile actionFile = getActionFile("offline/action_file_no_data.exi");
    try {
      actionFile.load();
      Assert.fail();
    } catch (IOException e) {
      // Expected exception.
    }
  }

  @Test
  public void testLoadIncompleteHeaderThrowsIOException() throws Exception {
    ActionFile actionFile = getActionFile("offline/action_file_incomplete_header.exi");
    try {
      actionFile.load();
      Assert.fail();
    } catch (IOException e) {
      // Expected exception.
    }
  }

  @Test
  public void testLoadZeroActions() throws Exception {
    ActionFile actionFile = getActionFile("offline/action_file_zero_actions.exi");
    DownloadRequest[] actions = actionFile.load();
    assertThat(actions).isNotNull();
    assertThat(actions).hasLength(0);
  }

  @Test
  public void testLoadOneAction() throws Exception {
    ActionFile actionFile = getActionFile("offline/action_file_one_action.exi");
    DownloadRequest[] actions = actionFile.load();
    assertThat(actions).hasLength(1);
    assertThat(actions[0]).isEqualTo(expectedAction1);
  }

  @Test
  public void testLoadTwoActions() throws Exception {
    ActionFile actionFile = getActionFile("offline/action_file_two_actions.exi");
    DownloadRequest[] actions = actionFile.load();
    assertThat(actions).hasLength(2);
    assertThat(actions[0]).isEqualTo(expectedAction1);
    assertThat(actions[1]).isEqualTo(expectedAction2);
  }

  @Test
  public void testLoadUnsupportedVersion() throws Exception {
    ActionFile actionFile = getActionFile("offline/action_file_unsupported_version.exi");
    try {
      actionFile.load();
      Assert.fail();
    } catch (IOException e) {
      // Expected exception.
    }
  }

  private ActionFile getActionFile(String fileName) throws IOException {
    // Copy the test data from the asset to where the ActionFile expects it to be.
    byte[] actionFileBytes =
        TestUtil.getByteArray(ApplicationProvider.getApplicationContext(), fileName);
    try (FileOutputStream output = new FileOutputStream(tempFile)) {
      output.write(actionFileBytes);
    }
    // Load the action file.
    return new ActionFile(tempFile);
  }

  private static DownloadRequest buildExpectedRequest(Uri uri, byte[] data) {
    return new DownloadRequest(
        /* id= */ uri.toString(),
        DownloadRequest.TYPE_PROGRESSIVE,
        uri,
        /* streamKeys= */ Collections.emptyList(),
        /* customCacheKey= */ null,
        data);
  }
}