Add a test for RLS, too

Author: ejona86

rls/src/test/java/io/grpc/rls/RlsLoadBalancerTest.java

@@ -42,6 +42,7 @@
 import io.grpc.ConnectivityStateInfo;
 import io.grpc.EquivalentAddressGroup;
 import io.grpc.ForwardingChannelBuilder2;
+import io.grpc.Grpc;
 import io.grpc.InternalManagedChannelBuilder;
 import io.grpc.LoadBalancer.CreateSubchannelArgs;
 import io.grpc.LoadBalancer.Helper;
@@ -371,8 +372,10 @@ public void metricsWithRealChannel() throws Exception {
         .build());
 
     StreamRecorder<Void> recorder = StreamRecorder.create();
+    CallOptions callOptions = CallOptions.DEFAULT
+        .withOption(Grpc.CALL_OPTION_CUSTOM_LABEL, "customvalue");
     StreamObserver<Void> requestObserver = ClientCalls.asyncClientStreamingCall(
-        channel.newCall(fakeSearchMethod, CallOptions.DEFAULT), recorder);
+        channel.newCall(fakeSearchMethod, callOptions), recorder);
     requestObserver.onCompleted();
     assertThat(recorder.awaitCompletion(10, TimeUnit.SECONDS)).isTrue();
     assertThat(recorder.getError()).isNull();
@@ -382,7 +385,7 @@ public void metricsWithRealChannel() throws Exception {
         eq(1L),
         eq(Arrays.asList("directaddress:///fake-bigtable.googleapis.com", "localhost:8972",
             "defaultTarget", "complete")),
-        eq(Arrays.asList("")));
+        eq(Arrays.asList("customvalue")));
   }
 
   @Test