[qa] test_framework: Exit when tmpdir exists

qa/rpc-tests/test_framework/test_framework.py

@@ -139,16 +139,11 @@ class BitcoinTestFramework(object):
 
         success = False
         try:
-            if not os.path.isdir(self.options.tmpdir):
+            os.makedirs(self.options.tmpdir, exist_ok=False)
-                os.makedirs(self.options.tmpdir)
             self.setup_chain()
-
             self.setup_network()
-
             self.run_test()
-
             success = True
-
         except JSONRPCException as e:
             print("JSONRPC error: "+e.error['message'])
             traceback.print_tb(sys.exc_info()[2])