Display help when ran without any arguments

CONTRIBUTORS.md

@@ -0,0 +1,5 @@
+Gistit contributors
+===================
+
+Hanish K H <hanish0019<at>gmail<dot>com>
+

gistit.py

@@ -98,6 +98,9 @@ def make_parser():
 def main():
     parser = make_parser()
     args = parser.parse_args()
+    if args.command is None:
+        parser.print_help()
+        sys.exit(1)
     command = args.func
     sys.exit(command(args))
 
@@ -335,3 +338,18 @@ def test_token(self):
 
     def test_create(self):
         self.assertReadmeContainsOutput(['create', '-h'])
+
+class SimpleRun(unittest.TestCase):
+    def setUp(self):
+        cmd_args = [sys.executable, 'gistit.py', '--help']
+        self.help_output_lines = subprocess.Popen(
+            cmd_args,
+            stdout=subprocess.PIPE).communicate()[0].decode('utf-8')
+
+    def test_no_args(self):
+        cmd_args = [sys.executable, 'gistit.py']
+        self.test_output_lines = subprocess.Popen(
+            cmd_args,
+            stdout=subprocess.PIPE).communicate()[0].decode('utf-8')
+        self.assertTrue(self.help_output_lines == self.test_output_lines)
+