[backport#16551] test: Pass down correct chain name in tests

Summary:
bitcoin/bitcoin@fa31dc1

---

Partial backport of Core [[bitcoin/bitcoin#16551 | PR16551]]

Test Plan:
  ./test/functional/test_runner.py

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D6430

test/functional/test_framework/mininode.py

@@ -115,7 +115,7 @@ def __init__(self):
     def is_connected(self):
         return self._transport is not None
 
-    def peer_connect(self, dstaddr, dstport, net="regtest"):
+    def peer_connect(self, dstaddr, dstport, *, net):
         assert not self.is_connected
         self.dstaddr = dstaddr
         self.dstport = dstport

test/functional/test_framework/test_node.py

@@ -481,7 +481,7 @@ def add_p2p_connection(self, p2p_conn, *, wait_for_verack=True, **kwargs):
         if 'dstaddr' not in kwargs:
             kwargs['dstaddr'] = '127.0.0.1'
 
-        p2p_conn.peer_connect(**kwargs)()
+        p2p_conn.peer_connect(**kwargs, net=self.chain)()
         self.p2ps.append(p2p_conn)
         if wait_for_verack:
             p2p_conn.wait_for_verack()

test/functional/test_framework/util.py

@@ -335,14 +335,22 @@ def initialize_datadir(dirname, n, chain):
     datadir = get_datadir_path(dirname, n)
     if not os.path.isdir(datadir):
         os.makedirs(datadir)
+    # Translate chain name to config name
+    if chain == 'testnet3':
+        chain_name_conf_arg = 'testnet'
+        chain_name_conf_section = 'test'
+    else:
+        chain_name_conf_arg = chain
+        chain_name_conf_section = chain
     with open(os.path.join(datadir, "bitcoin.conf"), 'w', encoding='utf8') as f:
-        f.write("{}=1\n".format(chain))
-        f.write("[{}]\n".format(chain))
+        f.write("{}=1\n".format(chain_name_conf_arg))
+        f.write("[{}]\n".format(chain_name_conf_section))
         f.write("port=" + str(p2p_port(n)) + "\n")
         f.write("rpcport=" + str(rpc_port(n)) + "\n")
         f.write("server=1\n")
         f.write("keypool=1\n")
         f.write("discover=0\n")
+        f.write("dnsseed=0\n")
         f.write("listenonion=0\n")
         f.write("usecashaddr=1\n")
         os.makedirs(os.path.join(datadir, 'stderr'), exist_ok=True)