content: /*
   * Copyright (C) 2018 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.server.backup.encryption.chunking;
  
  import static com.google.common.truth.Truth.assertThat;
  
  import static org.mockito.Mockito.mock;
  import static org.mockito.Mockito.verify;
  import static org.testng.Assert.assertThrows;
  
  import android.platform.test.annotations.Presubmit;
  
  import org.junit.After;
  import org.junit.Before;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.robolectric.RobolectricTestRunner;
  
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.util.Locale;
  
  /** Tests for {@link SingleStreamDiffScriptWriter}. */
  @RunWith(RobolectricTestRunner.class)
  @Presubmit
  public class SingleStreamDiffScriptWriterTest {
      private static final int MAX_CHUNK_SIZE_IN_BYTES = 256;
      /** By default this Locale does not use Arabic numbers for %d formatting. */
      private static final Locale HINDI = new Locale("hi", "IN");
  
      private Locale mDefaultLocale;
      private ByteArrayOutputStream mOutputStream;
      private SingleStreamDiffScriptWriter mDiffScriptWriter;
  
      @Before
      public void setUp() {
          mDefaultLocale = Locale.getDefault();
          mOutputStream = new ByteArrayOutputStream();
          mDiffScriptWriter =
                  new SingleStreamDiffScriptWriter(mOutputStream, MAX_CHUNK_SIZE_IN_BYTES);
      }
  
      @After
      public void tearDown() {
          Locale.setDefault(mDefaultLocale);
      }
  
      @Test
      public void writeChunk_withNegativeStart_throwsException() {
          assertThrows(
                  IllegalArgumentException.class,
                  () -> mDiffScriptWriter.writeChunk(-1, 50));
      }
  
      @Test
      public void writeChunk_withZeroLength_throwsException() {
          assertThrows(
                  IllegalArgumentException.class,
                  () -> mDiffScriptWriter.writeChunk(0, 0));
      }
  
      @Test
      public void writeChunk_withExistingBytesInBuffer_writesBufferFirst()
              throws IOException {
          String testString = "abcd";
          writeStringAsBytesToWriter(testString, mDiffScriptWriter);
  
          mDiffScriptWriter.writeChunk(0, 20);
          mDiffScriptWriter.flush();
  
          // Expected format: length of abcd, newline, abcd, newline, chunk start - chunk end
          assertThat(mOutputStream.toString("UTF-8")).isEqualTo(
                  String.format("%d\n%s\n%d-%d\n", testString.length(), testString, 0, 19));
      }
  
      @Test
      public void writeChunk_overlappingPreviousChunk_combinesChunks() throws IOException {
          mDiffScriptWriter.writeChunk(3, 4);
  
          mDiffScriptWriter.writeChunk(7, 5);
          mDiffScriptWriter.flush();
  
          assertThat(mOutputStream.toString("UTF-8")).isEqualTo(String.format("3-11\n"));
      }
  
      @Test
      public void writeChunk_formatsByteIndexesUsingArabicNumbers() throws Exception {
          Locale.setDefault(HINDI);
  
          mDiffScriptWriter.writeChunk(0, 12345);
          mDiffScriptWriter.flush();
  
          assertThat(mOutputStream.toString("UTF-8")).isEqualTo("0-12344\n");
      }
  
      @Test
      public void flush_flushesOutputStream() throws IOException {
          ByteArrayOutputStream mockOutputStream = mock(ByteArrayOutputStream.class);
          SingleStreamDiffScriptWriter diffScriptWriter =
                  new SingleStreamDiffScriptWriter(mockOutputStream, MAX_CHUNK_SIZE_IN_BYTES);
  
          diffScriptWriter.flush();
  
          verify(mockOutputStream).flush();
      }
  
      private void writeStringAsBytesToWriter(String string, SingleStreamDiffScriptWriter writer)
              throws IOException {
          byte[] bytes = string.getBytes("UTF-8");
          for (int i = 0; i < bytes.length; i++) {
              writer.writeByte(bytes[i]);
          }
      }
  }
  