Add test to expose http_client_asio bug

Author: Thomas Schaub

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

@@ -27,6 +27,9 @@
 #include "cpprest/http_listener.h"
 #endif
 
+#include <chrono>
+#include <thread>
+
 using namespace web;
 using namespace utility;
 using namespace concurrency;
@@ -400,6 +403,36 @@ TEST_FIXTURE(uri_address, cancel_while_downloading_data)
 }
 #endif
 
+// Try to connect to a server on a closed port and cancel the operation.
+TEST_FIXTURE(uri_address, cancel_bad_port)
+{
+    // http_client_asio has a bug where, when canceled, it will cancel only the
+    // current connection but then go and try the next address from the list of
+    // resolved addresses, i.e., it won't actually cancel as long as there are
+    // more addresses to try. Consequently, it will not report the task as being
+    // canceled. This is easiest to observe when trying to connect to a server
+    // that does not respond on a certain port, otherwise the timing might be
+    // tricky.
+
+    // We need to connect to a URI for which there are multiple addresses
+    // associated (i.e., multiple A records).
+    web::http::uri uri(U("https://microsoft.com:442/"));
+
+    // Send request.
+    http_client c(uri);
+    web::http::http_request r;
+    auto cts = pplx::cancellation_token_source();
+    auto ct = cts.get_token();
+    auto t = c.request(r, ct);
+
+    // Make sure that the client already finished resolving before canceling,
+    // otherwise the bug might not be triggered.
+    std::this_thread::sleep_for(std::chrono::seconds(1));
+    cts.cancel();
+
+    VERIFY_THROWS_HTTP_ERROR_CODE(t.get(), std::errc::operation_canceled);
+}
+
 } // SUITE(connections_and_errors)
 
 }}}}