Fix SonarConnectionMock by overriding virtual method

Summary: SonarConnection should have an `error` function; this stubs out the mock to have this, allowing creation for tests.

Reviewed By: jknoxville

Differential Revision: D8878130

fbshipit-source-id: 9e0f45dac4ba31ee650dfd46dcee51207cc7a9b4

xplat/SonarTestLib/SonarConnectionMock.h

@@ -26,6 +26,9 @@ class SonarConnectionMock : public SonarConnection {
     receivers_[method] = receiver;
   }
 
+  void error(const std::string& message, const std::string& stacktrace)
+      override {}
+
   std::map<std::string, folly::dynamic> sent_;
   std::map<std::string, SonarReceiver> receivers_;
 };