Test and refactor argument parsing

This patch does not change functionality of the argument parsing
function, but does make it easier to test. While argparse has its own
tests within the standard library and the `args` function could
theoretically be excluded, including these simple tests provide the
coverage we need without introducing the possibility of skipping over
code that might be added later.

Change-Id: I8ee11480ca6e46748fe19fcc19b92aded8a39c39

playbooks/inventory/dynamic_inventory.py

@@ -22,6 +22,7 @@ import netaddr
 import os
 import Queue
 import random
+import sys
 import tarfile
 import uuid
 import yaml
@@ -86,7 +87,7 @@ class MultipleIpForHostError(Exception):
         return self.message
 
 
-def args():
+def args(arg_list):
     """Setup argument Parsing."""
     parser = argparse.ArgumentParser(
         usage='%(prog)s',
@@ -105,7 +106,7 @@ def args():
         action='store_true'
     )
 
-    return vars(parser.parse_args())
+    return vars(parser.parse_args(arg_list))
 
 
 def get_ip_address(name, ip_q):
@@ -1142,6 +1143,6 @@ def main(all_args):
     return dynamic_inventory_json
 
 if __name__ == '__main__':
-    all_args = args()
+    all_args = args(sys.argv[1:])
     output = main(all_args)
     print(output)

tests/test_inventory.py

@@ -47,6 +47,21 @@ def get_inventory():
         cleanup()
 
 
+class TestArgParser(unittest.TestCase):
+    def test_no_args(self):
+        arg_dict = di.args([])
+        self.assertEqual(arg_dict['config'], None)
+        self.assertEqual(arg_dict['list'], False)
+
+    def test_list_arg(self):
+        arg_dict = di.args(['--list'])
+        self.assertEqual(arg_dict['list'], True)
+
+    def test_config_arg(self):
+        arg_dict = di.args(['--config', '/etc/openstack_deploy'])
+        self.assertEqual(arg_dict['config'], '/etc/openstack_deploy')
+
+
 class TestAnsibleInventoryFormatConstraints(unittest.TestCase):
     inventory = None