Make metrics export run on backend module

This fixes a previous issue where metrics generated on the
tools/backend modules weren't being successfully exported to BigQuery.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=119047757

javatests/com/google/domain/registry/flows/BUILD

@@ -31,6 +31,7 @@ java_library(
         "//java/com/google/domain/registry/flows",
         "//java/com/google/domain/registry/mapreduce",
         "//java/com/google/domain/registry/model",
+        "//java/com/google/domain/registry/monitoring/whitebox",
         "//java/com/google/domain/registry/request",
         "//java/com/google/domain/registry/security",
         "//java/com/google/domain/registry/security:servlets",

javatests/com/google/domain/registry/flows/EppServletTestCase.java

@@ -28,12 +28,14 @@ import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import com.google.appengine.api.modules.ModulesService;
 import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.domain.registry.model.ofy.Ofy;
 import com.google.domain.registry.model.registrar.Registrar;
 import com.google.domain.registry.model.tmch.ClaimsListShard.ClaimsListSingleton;
+import com.google.domain.registry.monitoring.whitebox.Metrics;
 import com.google.domain.registry.security.XsrfProtectedServlet;
 import com.google.domain.registry.testing.FakeClock;
 import com.google.domain.registry.testing.FakeServletInputStream;
@@ -74,6 +76,9 @@ public abstract class EppServletTestCase<S extends HttpServlet> {
   @Mock
   HttpServletResponse rsp;
 
+  @Mock
+  ModulesService modulesService;
+
   HttpSession session;
 
   FakeClock clock = new FakeClock();
@@ -96,6 +101,8 @@ public abstract class EppServletTestCase<S extends HttpServlet> {
   public final void init() throws Exception {
     inject.setStaticField(Ofy.class, "clock", clock);  // For transactional flows.
     inject.setStaticField(FlowRunner.class, "clock", clock);  // For non-transactional flows.
+    inject.setStaticField(Metrics.class, "modulesService", modulesService);
+    when(modulesService.getVersionHostname("backend", null)).thenReturn("backend.hostname");
 
     // Create RegistryData for all TLDs used in these tests.
     // We want to create all of these even for tests that don't use them to make sure that

javatests/com/google/domain/registry/monitoring/whitebox/MetricsTest.java

@@ -27,10 +27,10 @@ import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.junit.runners.JUnit4;
+import org.mockito.runners.MockitoJUnitRunner;
 
 /** Unit tests for {@link Metrics}. */
-@RunWith(JUnit4.class)
+@RunWith(MockitoJUnitRunner.class)
 public class MetricsTest {
 
   @Rule
@@ -39,6 +39,7 @@ public class MetricsTest {
   @Rule
   public final AppEngineRule appEngine = AppEngineRule.builder()
       .withDatastore()
+      .withLocalModules()
       .withTaskQueue()
       .build();
 
@@ -60,6 +61,7 @@ public class MetricsTest {
     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")