Fix more http test build fails in certain configurations (microsoft#1332)

Author: garethsb

Release/tests/functional/http/client/client_construction.cpp

@@ -173,7 +173,7 @@ SUITE(client_construction)
         VERIFY_ARE_EQUAL(baseclient2.base_uri(), m_uri);
     }
 
-#if defined(CPPREST_FORCE_HTTP_LISTENER_ASIO)
+#if !defined(_WIN32) && !defined(__cplusplus_winrt) || defined(CPPREST_FORCE_HTTP_CLIENT_ASIO)
 
     // Verify that the callback of sslcontext is called for HTTPS
     TEST_FIXTURE(uri_address, ssl_context_callback_https)

Release/tests/functional/http/listener/listener_construction_tests.cpp

@@ -549,9 +549,13 @@ XzJTD4slrGSJrcpLt/g/Jqqdjg==
         listener.open().wait();
 
         client::http_client_config client_config;
+#if !defined(_WIN32) && !defined(__cplusplus_winrt) || defined(CPPREST_FORCE_HTTP_CLIENT_ASIO)
         client_config.set_ssl_context_callback(
             [&](boost::asio::ssl::context& ctx) { ctx.add_certificate_authority(cert); });
-
+#else
+        // in this build configuration, with WinHTTP-based http_client, this test will fail unless the self-signed
+        // cert is added to the Windows certificate store (or certificate validation is disabled in client_config)
+#endif
         client::http_client client(m_secure_uri, client_config);
         http_request msg(methods::GET);
         msg.set_request_uri(U("/"));