Refactor EppMetrics into the EppMetric value type

This change refactors EppMetrics from the mutable self-exporting thing that it
was into a real value type EppMetric, and delegates exporting functionality to the
BigQueryMetricsEnqueuer.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=132387660

javatests/google/registry/monitoring/whitebox/BigQueryMetricsEnqueuerTest.java

@@ -0,0 +1,111 @@
+// 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.whitebox;
+
+import static google.registry.bigquery.BigqueryUtils.toBigqueryTimestamp;
+import static google.registry.testing.TaskQueueHelper.assertTasksEnqueued;
+import static org.mockito.Mockito.when;
+
+import com.google.api.services.bigquery.model.TableFieldSchema;
+import com.google.appengine.api.modules.ModulesService;
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import google.registry.testing.AppEngineRule;
+import google.registry.testing.InjectRule;
+import google.registry.testing.TaskQueueHelper.TaskMatcher;
+import org.joda.time.DateTime;
+import org.junit.Before;
+import org.junit.Rule;
+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 BigQueryMetricsEnqueuer}. */
+@RunWith(MockitoJUnitRunner.class)
+public class BigQueryMetricsEnqueuerTest {
+
+  @Rule
+  public final InjectRule inject = new InjectRule();
+
+  @Rule
+  public final AppEngineRule appEngine = AppEngineRule.builder()
+      .withDatastore()
+      .withLocalModules()
+      .withTaskQueue()
+      .build();
+
+  @Mock ModulesService modulesService;
+
+  private BigQueryMetricsEnqueuer enqueuer;
+
+  @Before
+  public void setUp() {
+    enqueuer = new BigQueryMetricsEnqueuer();
+    enqueuer.modulesService = modulesService;
+    when(modulesService.getVersionHostname(Matchers.anyString(), Matchers.anyString()))
+        .thenReturn("1.backend.test.localhost");
+  }
+
+  @Test
+  public void testExport() throws Exception {
+    TestMetric metric =
+        TestMetric.create(
+            DateTime.parse("1984-12-18TZ"), DateTime.parse("1984-12-18TZ").plusMillis(1));
+
+    enqueuer.export(metric, "laffo");
+
+    assertTasksEnqueued("bigquery-streaming-metrics",
+        new TaskMatcher()
+            .url("/_dr/task/metrics")
+            .header("Host", "1.backend.test.localhost")
+            .param("tableId", "test")
+            .param("startTime", "472176000.000000")
+            .param("endTime", "472176000.001000")
+            .param("insertId", "laffo"));
+  }
+
+  /** A stub implementation of {@link BigQueryMetric}. */
+  @AutoValue
+  abstract static class TestMetric implements BigQueryMetric {
+
+    static TestMetric create(DateTime startTimestamp, DateTime endTimestamp) {
+      return new AutoValue_BigQueryMetricsEnqueuerTest_TestMetric(startTimestamp, endTimestamp);
+    }
+
+    @Override
+    public String getTableId() {
+      return "test";
+    }
+
+    @Override
+    public ImmutableList<TableFieldSchema> getSchemaFields() {
+      return null;
+    }
+
+    @Override
+    public ImmutableMap<String, String> getBigQueryRowEncoding() {
+      return ImmutableMap.of(
+          "startTime", toBigqueryTimestamp(getStartTimestamp()),
+          "endTime", toBigqueryTimestamp(getEndTimestamp()));
+    }
+
+    abstract DateTime getStartTimestamp();
+
+    abstract DateTime getEndTimestamp();
+  }
+}