Add unittests and fix bugs

* Improved error messages
* Improved checking of user input

Signed-off-by: Jhon Honce <jhonce@redhat.com>

Closes: #978
Approved by: mheon

contrib/python/test/test_client.py

@@ -0,0 +1,37 @@
+from __future__ import absolute_import
+
+import unittest
+from unittest.mock import patch
+
+import podman
+from podman.client import BaseClient, Client, LocalClient, RemoteClient
+
+
+class TestClient(unittest.TestCase):
+    def setUp(self):
+        pass
+
+    @patch('podman.libs.system.System.ping', return_value=True)
+    def test_local(self, mock_ping):
+        p = Client(
+            uri='unix:/run/podman',
+            interface='io.projectatomic.podman',
+        )
+
+        self.assertIsInstance(p._client, LocalClient)
+        self.assertIsInstance(p._client, BaseClient)
+
+        mock_ping.assert_called_once()
+
+    @patch('os.path.isfile', return_value=True)
+    @patch('podman.libs.system.System.ping', return_value=True)
+    def test_remote(self, mock_ping, mock_isfile):
+        p = Client(
+            uri='unix:/run/podman',
+            interface='io.projectatomic.podman',
+            remote_uri='ssh://user@hostname/run/podmain/podman',
+            identity_file='~/.ssh/id_rsa')
+
+        self.assertIsInstance(p._client, BaseClient)
+        mock_ping.assert_called_once()
+        mock_isfile.assert_called_once()