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.transforms;
  
  import static org.hamcrest.MatcherAssert.assertThat;
  import static org.hamcrest.Matchers.instanceOf;
  import static org.junit.Assert.assertEquals;
  
  import java.io.Serializable;
  import org.apache.beam.sdk.coders.BigEndianLongCoder;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.KvCoder;
  import org.apache.beam.sdk.coders.NullableCoder;
  import org.apache.beam.sdk.coders.StringUtf8Coder;
  import org.apache.beam.sdk.coders.VarLongCoder;
  import org.apache.beam.sdk.testing.NeedsRunner;
  import org.apache.beam.sdk.testing.PAssert;
  import org.apache.beam.sdk.testing.TestPipeline;
  import org.apache.beam.sdk.values.KV;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.TimestampedValue;
  import org.joda.time.Instant;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.junit.rules.ExpectedException;
  import org.junit.runner.RunWith;
  import org.junit.runners.JUnit4;
  
  /** Unit tests for {@link Latest} {@link PTransform} and {@link Combine.CombineFn}. */
  @RunWith(JUnit4.class)
  public class LatestTest implements Serializable {
  
    @Rule public final transient TestPipeline p = TestPipeline.create();
    @Rule public transient ExpectedException thrown = ExpectedException.none();
  
    @Test
    @Category(NeedsRunner.class)
    public void testGloballyEventTimestamp() {
      PCollection<String> output =
          p.apply(
                  Create.timestamped(
                      TimestampedValue.of("foo", new Instant(100)),
                      TimestampedValue.of("bar", new Instant(300)),
                      TimestampedValue.of("baz", new Instant(200))))
              .apply(Latest.globally());
  
      PAssert.that(output).containsInAnyOrder("bar");
      p.run();
    }
  
    @Test
    public void testGloballyOutputCoder() {
      p.enableAbandonedNodeEnforcement(false);
  
      BigEndianLongCoder inputCoder = BigEndianLongCoder.of();
  
      PCollection<Long> output =
          p.apply(Create.of(1L, 2L).withCoder(inputCoder)).apply(Latest.globally());
  
      Coder<Long> outputCoder = output.getCoder();
      assertThat(outputCoder, instanceOf(NullableCoder.class));
      assertEquals(inputCoder, ((NullableCoder<?>) outputCoder).getValueCoder());
    }
  
    @Test
    @Category(NeedsRunner.class)
    public void testGloballyEmptyCollection() {
      PCollection<Long> emptyInput = p.apply(Create.empty(VarLongCoder.of()));
      PCollection<Long> output = emptyInput.apply(Latest.globally());
  
      PAssert.that(output).containsInAnyOrder((Long) null);
      p.run();
    }
  
    @Test
    @Category(NeedsRunner.class)
    public void testPerKeyEventTimestamp() {
      PCollection<KV<String, String>> output =
          p.apply(
                  Create.timestamped(
                      TimestampedValue.of(KV.of("A", "foo"), new Instant(100)),
                      TimestampedValue.of(KV.of("B", "bar"), new Instant(300)),
                      TimestampedValue.of(KV.of("A", "baz"), new Instant(200))))
              .apply(Latest.perKey());
  
      PAssert.that(output).containsInAnyOrder(KV.of("B", "bar"), KV.of("A", "baz"));
      p.run();
    }
  
    @Test
    public void testPerKeyOutputCoder() {
      p.enableAbandonedNodeEnforcement(false);
  
      KvCoder<String, Long> inputCoder = KvCoder.of(StringUtf8Coder.of(), BigEndianLongCoder.of());
  
      PCollection<KV<String, Long>> output =
          p.apply(Create.of(KV.of("foo", 1L)).withCoder(inputCoder)).apply(Latest.perKey());
  
      assertEquals("Should use input coder for outputs", inputCoder, output.getCoder());
    }
  
    @Test
    @Category(NeedsRunner.class)
    public void testPerKeyEmptyCollection() {
      PCollection<KV<String, String>> output =
          p.apply(Create.empty(KvCoder.of(StringUtf8Coder.of(), StringUtf8Coder.of())))
              .apply(Latest.perKey());
  
      PAssert.that(output).empty();
      p.run();
    }
  }
  