[cloud][tests] fixtures for placebo to test AWS modules using boto3 (#21253)

* [cloud][tests] Create fixtures for using placebo to test boto3-using modules

* Use pytest's importorskip instead of manually skipping on missing deps

* Fix imports in cloudformation module

* Delete unused code

* Add maybe_sleep fixtures to speed up recorded test runs

* Build basic placebo-CFN tests

* Commit placebo recordings of basic stack operations

* Add placebo to test-requires

* Allow unit tests to run regardless of environment by setting a default region

* Use explicit relative import for Python 3 compat

* Use __name__ attribute that works on Python 2 and 3

lib/ansible/modules/cloud/amazon/cloudformation.py

@@ -237,6 +237,8 @@ except ImportError:
 
 # import a class, otherwise we'll use a fully qualified path
 from ansible.module_utils.ec2 import AWSRetry
+from ansible.module_utils.basic import AnsibleModule
+import ansible.module_utils.ec2
 
 def boto_exception(err):
     '''generic error message handler'''
@@ -250,17 +252,6 @@ def boto_exception(err):
     return error
 
 
-def boto_version_required(version_tuple):
-    parts = boto3.__version__.split('.')
-    boto_version = []
-    try:
-        for part in parts:
-            boto_version.append(int(part))
-    except ValueError:
-        boto_version.append(-1)
-    return tuple(boto_version) >= tuple(version_tuple)
-
-
 def get_stack_events(cfn, stack_name):
     '''This event data was never correct, it worked as a side effect. So the v2.3 format is different.'''
     ret = {'events':[], 'log':[]}
@@ -507,10 +498,6 @@ def main():
             'directly to the CloudFormation API.')]
     module.exit_json(**result)
 
-# import module snippets
-from ansible.module_utils.basic import AnsibleModule
-import ansible.module_utils.ec2
-
 
 if __name__ == '__main__':
     main()