1 files changed, 16 insertions, 1 deletions
diff --git a/test/functional/test_framework/test_node.py b/test/functional/test_framework/test_node.py
index 8585972cb3..b515538a1a 100755
--- a/test/functional/test_framework/test_node.py
+++ b/test/functional/test_framework/test_node.py
@@ -387,6 +387,21 @@ class TestNode():
     def wait_until_stopped(self, timeout=BITCOIND_PROC_WAIT_TIMEOUT):
         wait_until_helper(self.is_node_stopped, timeout=timeout, timeout_factor=self.timeout_factor)
 
+    def replace_in_config(self, replacements):
+        """
+        Perform replacements in the configuration file.
+        The substitutions are passed as a list of search-replace-tuples, e.g.
+            [("old", "new"), ("foo", "bar"), ...]
+        """
+        with open(self.bitcoinconf, 'r', encoding='utf8') as conf:
+            conf_data = conf.read()
+        for replacement in replacements:
+            assert_equal(len(replacement), 2)
+            old, new = replacement[0], replacement[1]
+            conf_data = conf_data.replace(old, new)
+        with open(self.bitcoinconf, 'w', encoding='utf8') as conf:
+            conf.write(conf_data)
+
     @property
     def chain_path(self) -> Path:
         return Path(self.datadir) / self.chain
@@ -730,7 +745,7 @@ class TestNodeCLI():
             p_args += [command]
         p_args += pos_args + named_args
         self.log.debug("Running bitcoin-cli {}".format(p_args[2:]))
-        process = subprocess.Popen(p_args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
+        process = subprocess.Popen(p_args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
         cli_stdout, cli_stderr = process.communicate(input=self.input)
         returncode = process.poll()
         if returncode: