Ruby wrapping of core credentials API change.
diff --git a/src/ruby/spec/channel_spec.rb b/src/ruby/spec/channel_spec.rb
index 25cefcd..b4d2b94 100644
--- a/src/ruby/spec/channel_spec.rb
+++ b/src/ruby/spec/channel_spec.rb
@@ -40,7 +40,7 @@
   let(:cq) { GRPC::Core::CompletionQueue.new }
 
   def create_test_cert
-    GRPC::Core::Credentials.new(load_test_certs[0])
+    GRPC::Core::ChannelCredentials.new(load_test_certs[0])
   end
 
   shared_examples '#new' do