test: basic signet tests

test/functional/test_framework/p2p.py

@@ -109,6 +109,7 @@ MAGIC_BYTES = {
     "mainnet": b"\xf9\xbe\xb4\xd9",   # mainnet
     "testnet3": b"\x0b\x11\x09\x07",  # testnet3
     "regtest": b"\xfa\xbf\xb5\xda",   # regtest
+    "signet": b"\x0a\x03\xcf\x40",    # signet
 }