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/VirtualMetricTest.java

@@ -0,0 +1,64 @@
+// 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 com.google.common.base.Suppliers;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import org.joda.time.Instant;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Unit tests for {@link VirtualMetric}. */
+@RunWith(JUnit4.class)
+public class VirtualMetricTest {
+
+  private final VirtualMetric<String> metric =
+      new VirtualMetric<>(
+          "/metric",
+          "description",
+          "vdn",
+          ImmutableSet.of(LabelDescriptor.create("label1", "bar")),
+          Suppliers.ofInstance(
+              ImmutableMap.of(
+                  ImmutableList.of("label_value1"), "value1",
+                  ImmutableList.of("label_value2"), "value2")),
+          String.class);
+
+  @Test
+  public void testGetCardinality_afterGetTimestampedValues_returnsLastCardinality() {
+    metric.getTimestampedValues();
+    assertThat(metric.getCardinality()).isEqualTo(2);
+  }
+
+  @Test
+  public void testGetCardinality_beforeGetTimestampedValues_returnsZero() {
+    assertThat(metric.getCardinality()).isEqualTo(0);
+  }
+
+  @Test
+  public void testGetTimestampedValues_returnsValues() {
+    assertThat(metric.getTimestampedValues(new Instant(1337)))
+        .containsExactly(
+            MetricPoint.create(
+                metric, ImmutableList.of("label_value1"), new Instant(1337), "value1"),
+            MetricPoint.create(
+                metric, ImmutableList.of("label_value2"), new Instant(1337), "value2"));
+  }
+}