Use run_test() for service.is_masked()

Followup 3a027cc, we should expect exit code 0 or 1 here.

Author: philpep

testinfra/modules/service.py

@@ -152,7 +152,7 @@ def is_valid(self):
 
     @property
     def is_masked(self):
-        cmd = self.run("systemctl is-enabled %s", self.name)
+        cmd = self.run_test("systemctl is-enabled %s", self.name)
         return cmd.rc == 0 and cmd.stdout.strip() == "masked"