Preserve explicit Paramiko username

test/test_backends.py

@@ -13,6 +13,7 @@
 import operator
 import os
 import tempfile
+from io import StringIO
 
 import pytest
 
@@ -621,6 +622,25 @@ def test_ssh_hostspec(hostspec, expected):
     assert command == expected
 
 
+def test_paramiko_ssh_config_does_not_override_explicit_user():
+    import paramiko
+
+    from testinfra.backend.paramiko import ParamikoBackend
+
+    ssh_config = paramiko.SSHConfig()
+    ssh_config.parse(StringIO("Host *\n  User configuser\n"))
+
+    backend = ParamikoBackend("explicit@example.com")
+    cfg = {"username": backend.host.user}
+    backend._load_ssh_config(paramiko.SSHClient(), cfg, ssh_config)
+    assert cfg["username"] == "explicit"
+
+    backend = ParamikoBackend("example.com")
+    cfg = {"username": backend.host.user}
+    backend._load_ssh_config(paramiko.SSHClient(), cfg, ssh_config)
+    assert cfg["username"] == "configuser"
+
+
 def test_get_hosts():
     # Hosts returned by get_host must be deduplicated (by name & kwargs) and in
     # same order as asked

testinfra/backend/paramiko.py

@@ -68,7 +68,8 @@ def _load_ssh_config(
             if key == "hostname":
                 cfg[key] = value
             elif key == "user":
-                cfg["username"] = value
+                if cfg.get("username") is None:
+                    cfg["username"] = value
             elif key == "port":
                 cfg[key] = int(value)
             elif key == "identityfile":