Add tests for UTMP methods

kitty_tests/utmp.py

@@ -0,0 +1,13 @@
+from sys import platform
+
+if platform in ('linux', 'linux2'):
+    import subprocess
+    import re
+    from kitty.fast_data_types import num_users
+    from . import BaseTest
+
+    class UTMPTest(BaseTest):
+        def test_num_users(self):
+            # who -q is the control
+            expected = subprocess.run(['who'], capture_output=True).stdout.decode('utf-8').count('\n')
+            self.ae(num_users(), expected)