Add docstrings to User and Group .exists properties.

Author: disser

testinfra/modules/group.py

@@ -22,6 +22,15 @@ def __init__(self, name=None):
 
     @property
     def exists(self):
+        """Test if group exists
+
+        >>> host.group("wheel").exists
+        True
+        >>> host.group("nosuchgroup").exists
+        False
+
+        """
+
         return self.run_expect([0, 2], "getent group %s", self.name).rc == 0
 
     @property

testinfra/modules/user.py

@@ -34,6 +34,15 @@ def name(self):
 
     @property
     def exists(self):
+        """Test if user exists
+
+        >>> host.user("root").exists
+        True
+        >>> host.user("nosuchuser").exists
+        False
+
+        """
+
         return self.run_test("id %s", self.name).rc == 0
 
     @property
@@ -145,6 +154,15 @@ def name(self):
 
     @property
     def exists(self):
+        """Test if user exists
+
+        >>> host.user("Administrator").exists
+        True
+        >>> host.user("nosuchuser").exists
+        False
+
+        """
+
         return self.run_test("net user %s", self.name).rc == 0
 
     @property