Simulate the lora up/downlinks to and fro from Chirpstack Server without actual device

Is there any way that we can simulate the lora uplink and downlink messages to and fro from Chirpstack Server without existence of actual gateway and Lora-end device. Please suggest the way arround that we can recieve uplink of our running Chirpstack server without actual device/gateway if similar code or application or simulator is available for testing purpose

Search the forum for LoRaWAN simulator. There are a few options.