sdks/java/core/src/test/java/org/apache/beam/sdk/coders/MapCoderTest.java

/*
 * 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.hamcrest.Matchers.equalTo;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.assertTrue;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
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.sdk.values.TypeDescriptor;
import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableMap;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Unit tests for {@link MapCoder}. */
@RunWith(JUnit4.class)
public class MapCoderTest {

  private static final Coder<Map<Integer, String>> TEST_CODER =
      MapCoder.of(VarIntCoder.of(), StringUtf8Coder.of());

  private static final List<Map<Integer, String>> TEST_VALUES =
      Arrays.asList(
          Collections.emptyMap(),
          new TreeMap<>(
              new ImmutableMap.Builder<Integer, String>().put(1, "hello").put(-1, "foo").build()));

  @Test
  public void testDecodeEncodeContentsInSameOrder() throws Exception {
    for (Map<Integer, String> value : TEST_VALUES) {
      CoderProperties.coderDecodeEncodeEqual(TEST_CODER, value);
    }
  }

  @Test
  public void testCoderIsSerializableWithWellKnownCoderType() throws Exception {
    CoderProperties.coderSerializable(
        MapCoder.of(GlobalWindow.Coder.INSTANCE, GlobalWindow.Coder.INSTANCE));
  }

  /**
   * Generated data to check that the wire format has not changed. To regenerate, see {@link
   * org.apache.beam.sdk.coders.PrintBase64Encodings}.
   */
  private static final List<String> TEST_ENCODINGS =
      Arrays.asList("AAAAAA", "AAAAAv____8PA2ZvbwFoZWxsbw");

  @Test
  public void testWireFormatEncode() throws Exception {
    CoderProperties.coderEncodesBase64(TEST_CODER, TEST_VALUES, TEST_ENCODINGS);
  }

  @Rule public ExpectedException thrown = ExpectedException.none();

  @Test
  public void encodeNullThrowsCoderException() throws Exception {
    thrown.expect(CoderException.class);
    thrown.expectMessage("cannot encode a null Map");

    CoderUtils.encodeToBase64(TEST_CODER, null);
  }

  @Test
  public void testStructuralValueDecodeEncodeEqual() throws Exception {
    MapCoder<byte[], Integer> coder = MapCoder.of(ByteArrayCoder.of(), VarIntCoder.of());
    Map<byte[], Integer> value = Collections.singletonMap(new byte[] {1, 2, 3, 4}, 1);
    CoderProperties.structuralValueDecodeEncodeEqual(coder, value);
  }

  @Test
  public void testNotConsistentWithEquals() {
    MapCoder<Integer, byte[]> coder = MapCoder.of(VarIntCoder.of(), ByteArrayCoder.of());
    assertFalse(coder.consistentWithEquals());
  }

  @Test
  public void testConsistentWithEquals() {
    MapCoder<Integer, Integer> coder = MapCoder.of(VarIntCoder.of(), VarIntCoder.of());
    assertTrue(coder.consistentWithEquals());
  }

  @Test
  public void testEncodedTypeDescriptor() throws Exception {
    TypeDescriptor<Map<Integer, String>> typeDescriptor =
        new TypeDescriptor<Map<Integer, String>>() {};
    assertThat(TEST_CODER.getEncodedTypeDescriptor(), equalTo(typeDescriptor));
  }
}