content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.beam.sdk.coders;
  
  import static org.junit.Assert.assertArrayEquals;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  
  import java.util.Arrays;
  import java.util.List;
  import org.apache.beam.sdk.testing.CoderProperties;
  import org.apache.beam.sdk.transforms.windowing.GlobalWindow;
  import org.apache.beam.sdk.util.CoderUtils;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.junit.runners.JUnit4;
  
  /** Tests for {@link LengthPrefixCoder}. */
  @RunWith(JUnit4.class)
  public class LengthPrefixCoderTest {
    private static final StructuredCoder<byte[]> TEST_CODER =
        LengthPrefixCoder.of(ByteArrayCoder.of());
  
    private static final List<byte[]> TEST_VALUES =
        Arrays.asList(
            new byte[] {0xa, 0xb, 0xc}, new byte[] {0xd, 0x3}, new byte[] {0xd, 0xe}, new byte[] {});
  
    /**
     * Generated data to check that the wire format has not changed. To regenerate, see {@link
     * org.apache.beam.sdk.coders.PrintBase64Encodings}.
     */
    private static final ImmutableList<String> TEST_ENCODINGS =
        ImmutableList.of("AwoLDA", "Ag0D", "Ag0O", "AA");
  
    @Test
    public void testCoderSerializable() throws Exception {
      CoderProperties.coderSerializable(TEST_CODER);
    }
  
    @Test
    public void testCoderIsSerializableWithWellKnownCoderType() throws Exception {
      CoderProperties.coderSerializable(LengthPrefixCoder.of(GlobalWindow.Coder.INSTANCE));
    }
  
    @Test
    public void testEncodedSize() throws Exception {
      assertEquals(5L, TEST_CODER.getEncodedElementByteSize(TEST_VALUES.get(0)));
    }
  
    @Test
    public void testObserverIsCheap() throws Exception {
      LengthPrefixCoder<Double> coder = LengthPrefixCoder.of(DoubleCoder.of());
      assertTrue(coder.isRegisterByteSizeObserverCheap(5.0));
    }
  
    @Test
    public void testObserverIsNotCheap() throws Exception {
      LengthPrefixCoder<List<String>> coder =
          LengthPrefixCoder.of(ListCoder.of(StringUtf8Coder.of()));
      assertFalse(coder.isRegisterByteSizeObserverCheap(ImmutableList.of("hi", "test")));
    }
  
    @Test
    public void testDecodeEncodeEquals() throws Exception {
      for (byte[] value : TEST_VALUES) {
        CoderProperties.coderDecodeEncodeEqual(TEST_CODER, value);
      }
    }
  
    @Test
    public void testRegisterByteSizeObserver() throws Exception {
      CoderProperties.testByteCount(
          LengthPrefixCoder.of(VarIntCoder.of()), Coder.Context.NESTED, new Integer[] {0, 10, 1000});
    }
  
    @Test
    public void testStructuralValueConsistentWithEquals() throws Exception {
      for (byte[] value1 : TEST_VALUES) {
        for (byte[] value2 : TEST_VALUES) {
          CoderProperties.structuralValueConsistentWithEquals(TEST_CODER, value1, value2);
        }
      }
    }
  
    @Test
    public void testWireFormatEncode() throws Exception {
      CoderProperties.coderEncodesBase64(TEST_CODER, TEST_VALUES, TEST_ENCODINGS);
    }
  
    @Test
    public void testMultiCoderCycle() throws Exception {
      LengthPrefixCoder<Long> lengthPrefixedValueCoder =
          LengthPrefixCoder.of(BigEndianLongCoder.of());
  
      LengthPrefixCoder<byte[]> lengthPrefixedBytesCoder = LengthPrefixCoder.of(ByteArrayCoder.of());
  
      // [0x08, 0, 0, 0, 0, 0, 0, 0, 0x16]
      byte[] userEncoded = CoderUtils.encodeToByteArray(lengthPrefixedValueCoder, 22L);
  
      // [0, 0, 0, 0, 0, 0, 0, 0x16]
      byte[] decodedToBytes = CoderUtils.decodeFromByteArray(lengthPrefixedBytesCoder, userEncoded);
  
      // [0x08, 0, 0, 0, 0, 0, 0, 0, 0x16]
      byte[] reencodedBytes = CoderUtils.encodeToByteArray(lengthPrefixedBytesCoder, decodedToBytes);
  
      long userDecoded = CoderUtils.decodeFromByteArray(lengthPrefixedValueCoder, reencodedBytes);
  
      assertFalse(
          "Length-prefix decoding to bytes should drop the length",
          Arrays.equals(userEncoded, decodedToBytes));
      assertArrayEquals(userEncoded, reencodedBytes);
      assertEquals(22L, userDecoded);
    }
  }
  