okhttp: cleanup channel in channel builder tests

okhttp/src/test/java/io/grpc/okhttp/OkHttpChannelBuilderTest.java

@@ -24,10 +24,12 @@
 
 import com.squareup.okhttp.ConnectionSpec;
 import io.grpc.ChannelLogger;
+import io.grpc.ManagedChannel;
 import io.grpc.internal.ClientTransportFactory;
 import io.grpc.internal.FakeClock;
 import io.grpc.internal.GrpcUtil;
 import io.grpc.internal.SharedResourceHolder;
+import io.grpc.testing.GrpcCleanupRule;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.Socket;
@@ -46,11 +48,13 @@
 public class OkHttpChannelBuilderTest {
 
   @Rule public final ExpectedException thrown = ExpectedException.none();
+  @Rule public final GrpcCleanupRule grpcCleanupRule = new GrpcCleanupRule();
 
   @Test
   public void authorityIsReadable() {
     OkHttpChannelBuilder builder = OkHttpChannelBuilder.forAddress("original", 1234);
-    assertEquals("original:1234", builder.build().authority());
+    ManagedChannel channel = grpcCleanupRule.register(builder.build());
+    assertEquals("original:1234", channel.authority());
   }
 
   @Test
@@ -68,7 +72,8 @@ public void overrideAuthorityIsReadableForTarget() {
   private void overrideAuthorityIsReadableHelper(OkHttpChannelBuilder builder,
       String overrideAuthority) {
     builder.overrideAuthority(overrideAuthority);
-    assertEquals(overrideAuthority, builder.build().authority());
+    ManagedChannel channel = grpcCleanupRule.register(builder.build());
+    assertEquals(overrideAuthority, channel.authority());
   }
 
   @Test