Split basic units (#33510)

Split the one monolithic test for basic.py into several files

* Split test_basic.py along categories.
  This is preliminary to get a handle on things.  Eventually we may want
  to further split it so each file is only testing a single function.
* Cleanup unused imports from splitting test_basic.py
* Port atomic_move test to pytest.
  Working on getting rid of need to maintain procenv
* Split a test of symbolic_mode_to_octal to follow unittest best practices
  Each test should only invoke the function under test once
* Port test_argument_spec to pytest.
* Fix suboptions failure

test/units/module_utils/basic/test_dict_converters.py

@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+# (c) 2012-2014, Michael DeHaan <michael.dehaan@gmail.com>
+# (c) 2016 Toshio Kuratomi <tkuratomi@ansible.com>
+# (c) 2017 Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
+from units.mock.procenv import ModuleTestCase
+
+from ansible.module_utils.six.moves import builtins
+
+realimport = builtins.__import__
+
+
+class TestTextifyContainers(ModuleTestCase):
+    def test_module_utils_basic_json_dict_converters(self):
+        from ansible.module_utils.basic import json_dict_unicode_to_bytes, json_dict_bytes_to_unicode
+
+        test_data = dict(
+            item1=u"Fóo",
+            item2=[u"Bár", u"Bam"],
+            item3=dict(sub1=u"Súb"),
+            item4=(u"föo", u"bär", u"©"),
+            item5=42,
+        )
+        res = json_dict_unicode_to_bytes(test_data)
+        res2 = json_dict_bytes_to_unicode(res)
+
+        self.assertEqual(test_data, res2)