rpc: Add wait argument to stop

src/rpc/client.cpp

@@ -162,6 +162,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "rescanblockchain", 1, "stop_height"},
     { "createwallet", 1, "disable_private_keys"},
     { "getnodeaddresses", 0, "count"},
+    { "stop", 0, "wait" },
 };
 // clang-format on
 

src/rpc/server.cpp

@@ -227,6 +227,9 @@ UniValue help(const JSONRPCRequest& jsonRequest)
 UniValue stop(const JSONRPCRequest& jsonRequest)
 {
     // Accept the deprecated and ignored 'detach' boolean argument
+    // Also accept the hidden 'wait' integer argument (milliseconds)
+    // For instance, 'stop 1000' makes the call wait 1 second before returning
+    // to the client (intended for testing)
     if (jsonRequest.fHelp || jsonRequest.params.size() > 1)
         throw std::runtime_error(
             RPCHelpMan{"stop",
@@ -235,6 +238,9 @@ UniValue stop(const JSONRPCRequest& jsonRequest)
     // Event loop will exit after current HTTP requests have been handled, so
     // this reply will get back to the client.
     StartShutdown();
+    if (jsonRequest.params[0].isNum()) {
+        MilliSleep(jsonRequest.params[0].get_int());
+    }
     return "Bitcoin server stopping";
 }
 
@@ -264,7 +270,7 @@ static const CRPCCommand vRPCCommands[] =
   //  --------------------- ------------------------  -----------------------  ----------
     /* Overall control/query calls */
     { "control",            "help",                   &help,                   {"command"}  },
-    { "control",            "stop",                   &stop,                   {}  },
+    { "control",            "stop",                   &stop,                   {"wait"}  },
     { "control",            "uptime",                 &uptime,                 {}  },
 };
 // clang-format on