diff --git a/tools/test-networkmanager-service.py b/tools/test-networkmanager-service.py
index 9002f26b36..8221804143 100755
--- a/tools/test-networkmanager-service.py
+++ b/tools/test-networkmanager-service.py
@@ -288,8 +288,15 @@ class Util:
         return (Util.ip_addr_ntop(a, family), family)
 
     @staticmethod
-    def eprint(*args, **kwargs):
-        print(*args, file=sys.stderr, **kwargs)
+    def log(message):
+        if gl.log_file:
+            try:
+                gl.log_file.write(message + "\n")
+                gl.log_file.flush()
+            except Exception:
+                pass
+        else:
+            print(message, file=sys.stderr)
 
     @staticmethod
     def variant_from_dbus(val):
@@ -308,9 +315,9 @@ class Util:
         if isinstance(val, dbus.Array):
             try:
                 if val.signature == "s":
-                    return GLib.Variant("as", [Util.variant_from_dbus(x) for x in val])
+                    return GLib.Variant("as", [str(x) for x in val])
                 if val.signature == "b":
-                    return GLib.Variant("ab", [Util.variant_from_dbus(x) for x in val])
+                    return GLib.Variant("ab", [bool(x) for x in val])
                 if val.signature == "y":
                     return GLib.Variant("ay", [int(x) for x in val])
                 if val.signature == "u":
@@ -342,8 +349,7 @@ class Util:
                     )
             except Exception as e:
                 raise Exception(
-                    "Cannot convert array element to type '%s': %s"
-                    % (val.signature, e.message)
+                    "Cannot convert array element to type '%s': %s" % (val.signature, e)
                 )
         if isinstance(val, dbus.Dictionary):
             if val.signature == "ss":
@@ -2884,6 +2890,26 @@ class ObjectManager(dbus.service.Object):
         return managed_objects
 
 
+def setup_log_file():
+    """
+    Get environment variable for the log file , if any
+    We accept a %p placeholder to replace with the pid of the current
+    process
+    """
+    try:
+        log_file_name = os.environ["NM_TEST_NETWORKMANAGER_SERVICE_LOGFILE"]
+    except KeyError:
+        return None
+    if "%p" in log_file_name:
+        log_file_name = log_file_name.replace("%p", str(os.getpid()))
+    try:
+        log_file = open(log_file_name, "w")
+    except Exception:
+        log_file = None
+
+    return log_file
+
+
 ###############################################################################
 
 
@@ -2895,6 +2921,7 @@ def main():
     global gl
     gl = Global()
 
+    gl.log_file = setup_log_file()
     gl.mainloop = GLib.MainLoop()
     gl.bus = dbus.SessionBus()
     gl.force_activation_failure = {}
@@ -2927,7 +2954,8 @@ def main():
     gl.settings.unexport()
     gl.manager.unexport()
     gl.object_manager.remove_from_connection()
-
+    if gl.log_file:
+        gl.log_file.close()
     sys.exit(0)