Add more tests to external code repo

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=131406104

javatests/google/registry/monitoring/metrics/MetricExporterTest.java

@@ -0,0 +1,130 @@
+// Copyright 2016 The Domain Registry Authors. All Rights Reserved.
+//
+// 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 google.registry.monitoring.metrics;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.junit.Assert.fail;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import com.google.common.base.Optional;
+import com.google.common.collect.ImmutableList;
+import com.google.common.util.concurrent.Service.State;
+import java.io.IOException;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Matchers;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+
+/** Unit tests for {@link MetricExporter}. */
+@RunWith(MockitoJUnitRunner.class)
+public class MetricExporterTest {
+
+  @Mock private MetricWriter writer;
+  @Mock private MetricPoint<?> point;
+  private MetricExporter exporter;
+  private BlockingQueue<Optional<ImmutableList<MetricPoint<?>>>> writeQueue;
+  private final Optional<ImmutableList<MetricPoint<?>>> poisonPill = Optional.absent();
+  private final Optional<ImmutableList<MetricPoint<?>>> emptyBatch =
+      Optional.of(ImmutableList.<MetricPoint<?>>of());
+
+  @Before
+  public void setUp() throws Exception {
+    writeQueue = new ArrayBlockingQueue<>(1);
+    exporter = new MetricExporter(writeQueue, writer, Executors.defaultThreadFactory());
+  }
+
+  @Test
+  public void testRun_takesFromQueue_whileRunning() throws Exception {
+    exporter.startAsync().awaitRunning();
+
+    insertAndAssert(emptyBatch);
+    // Insert more batches to verify that the exporter hasn't gotten stuck
+    insertAndAssert(emptyBatch);
+    insertAndAssert(emptyBatch);
+
+    assertThat(exporter.state()).isEqualTo(State.RUNNING);
+  }
+
+  @Test
+  public void testRun_terminates_afterPoisonPill() throws Exception {
+    exporter.startAsync().awaitRunning();
+
+    insertAndAssert(poisonPill);
+    try {
+      exporter.awaitTerminated(500, TimeUnit.MILLISECONDS);
+    } catch (TimeoutException timeout) {
+      fail("MetricExporter did not reach the TERMINATED state after receiving a poison pill");
+    }
+
+    assertThat(exporter.state()).isEqualTo(State.TERMINATED);
+  }
+
+  @Test
+  public void testRun_staysRunning_afterIOException() throws Exception {
+    Optional<ImmutableList<MetricPoint<?>>> threeBatch =
+        Optional.of(ImmutableList.of(point, point, point));
+    doThrow(new IOException()).when(writer).write(Matchers.<MetricPoint<?>>any());
+    exporter.startAsync();
+
+    insertAndAssert(threeBatch);
+    // Insert another batch in order to block until the exporter has processed the last one
+    insertAndAssert(threeBatch);
+    // Insert another to make sure the exporter hasn't gotten stuck
+    insertAndAssert(threeBatch);
+
+    assertThat(exporter.state()).isNotEqualTo(State.FAILED);
+  }
+
+  @Test
+  public void testRun_writesMetrics() throws Exception {
+    Optional<ImmutableList<MetricPoint<?>>> threeBatch =
+        Optional.of(ImmutableList.of(point, point, point));
+    exporter.startAsync();
+
+    insertAndAssert(threeBatch);
+    // Insert another batch in order to block until the exporter has processed the last one
+    insertAndAssert(threeBatch);
+
+    // Force the exporter to finish so that the verify counts below are deterministic
+    insertAndAssert(poisonPill);
+    try {
+      exporter.awaitTerminated(500, TimeUnit.MILLISECONDS);
+    } catch (TimeoutException timeout) {
+      fail("MetricExporter did not reach the TERMINATED state after receiving a poison pill");
+    }
+
+    assertThat(exporter.state()).isNotEqualTo(State.FAILED);
+    verify(writer, times(6)).write(point);
+    verify(writer, times(2)).flush();
+  }
+
+  /**
+   * Helper method to insert into the {@link BlockingQueue} and assert that the item has been
+   * enqueued.
+   */
+  private void insertAndAssert(Optional<ImmutableList<MetricPoint<?>>> batch) throws Exception {
+    boolean isTaken = writeQueue.offer(batch, 500, TimeUnit.MILLISECONDS);
+    assertThat(isTaken).isTrue();
+  }
+}