Fix failing assert in connect RPC (#5235)

src/test/rpc/Connect_test.cpp

@@ -0,0 +1,59 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2025 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <test/jtx.h>
+#include <xrpl/protocol/jss.h>
+
+namespace ripple {
+
+class Connect_test : public beast::unit_test::suite
+{
+    void
+    testErrors()
+    {
+        testcase("Errors");
+
+        using namespace test::jtx;
+
+        {
+            // standalone mode should fail
+            Env env{*this};
+            BEAST_EXPECT(env.app().config().standalone());
+
+            auto const result = env.rpc("json", "connect", "{}");
+            BEAST_EXPECT(result[jss::result][jss::status] == "error");
+            BEAST_EXPECT(result[jss::result].isMember(jss::error));
+            BEAST_EXPECT(result[jss::result][jss::error] == "notSynced");
+            BEAST_EXPECT(
+                result[jss::result][jss::error_message] ==
+                "Not synced to the network.");
+        }
+    }
+
+public:
+    void
+    run() override
+    {
+        testErrors();
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(Connect, rpc, ripple);
+
+}  // namespace ripple

src/xrpld/rpc/handlers/Connect.cpp

@@ -38,7 +38,9 @@ Json::Value
 doConnect(RPC::JsonContext& context)
 {
     if (context.app.config().standalone())
-        return "cannot connect in standalone mode";
+    {
+        return RPC::make_error(rpcNOT_SYNCED);
+    }
 
     if (!context.params.isMember(jss::ip))
         return RPC::missing_field_error(jss::ip);