[Resolves #570] Improve Stack.__repr__()

Previously, dict and list types were contained within strings in
sceptre.stack.Stack.__repr__(). This commit removes the strings so that
a stack.__repr__() can be used to create a stack using eval().

In order to properly compare stacks a custom `__eq__` and therefore
`__hash__` implementations were added to Stack. Adding a correct `__eq__`
method to Stack allowed testing of Stack objects that were created from
`eval()` of the stack `__repr__`.

sceptre/stack.py

@@ -145,21 +145,27 @@ def __init__(
  def __repr__(self):
  return (
  "sceptre.stack.Stack("
- "name='{name}', project_code='{project_code}', "
- "template_path='{template_path}', region='{region}', "
- "template_bucket_name='{template_bucket_name}', "
- "template_key_prefix='{template_key_prefix}', "
- "required_version='{required_version}', "
- "profile='{profile}', "
- "sceptre_user_data='{sceptre_user_data}', "
- "parameters='{parameters}', "
- "hooks='{hooks}', s3_details='{s3_details}', "
- "dependencies='{dependencies}', role_arn='{role_arn}', "
- "protected='{protected}', tags='{tags}', "
- "external_name='{external_name}', "
- "notifications='{notifications}', on_failure='{on_failure}', "
- "stack_timeout='{stack_timeout}', "
- "stack_group_config='{stack_group_config}'"
+ "name={name}, "
+ "project_code={project_code}, "
+ "template_path={template_path}, "
+ "region={region}, "
+ "template_bucket_name={template_bucket_name}, "
+ "template_key_prefix={template_key_prefix}, "
+ "required_version={required_version}, "
+ "profile={profile}, "
+ "sceptre_user_data={sceptre_user_data}, "
+ "parameters={parameters}, "
+ "hooks={hooks}, "
+ "s3_details={s3_details}, "
+ "dependencies={dependencies}, "
+ "role_arn={role_arn}, "
+ "protected={protected}, "
+ "tags={tags}, "
+ "external_name={external_name}, "
+ "notifications={notifications}, "
+ "on_failure={on_failure}, "
+ "stack_timeout={stack_timeout}, "
+ "stack_group_config={stack_group_config}"
  ")".format(
  name=self.name,
  project_code=self.project_code,
@@ -188,6 +194,34 @@ def __repr__(self):
  def __str__(self):
  return self.name
 
+ def __eq__(self, stack):
+ return (
+ self.name == stack.name and
+ self.project_code == stack.project_code and
+ self.template_path == stack.template_path and
+ self.region == stack.region and
+ self.template_bucket_name == stack.template_bucket_name and
+ self.template_key_prefix == stack.template_key_prefix and
+ self.required_version == stack.required_version and
+ self.profile == stack.profile and
+ self.sceptre_user_data == stack.sceptre_user_data and
+ self.parameters == stack.parameters and
+ self.hooks == stack.hooks and
+ self.s3_details == stack.s3_details and
+ self.dependencies == stack.dependencies and
+ self.role_arn == stack.role_arn and
+ self.protected == stack.protected and
+ self.tags == stack.tags and
+ self.external_name == stack.external_name and
+ self.notifications == stack.notifications and
+ self.on_failure == stack.on_failure and
+ self.stack_timeout == stack.stack_timeout and
+ self.stack_group_config == stack.stack_group_config
+ )
+
+ def __hash__(self):
+ return hash(str(self))
+
  @property
  def template(self):
  """

tests/test_stack.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 
+import importlib
 from mock import sentinel, MagicMock
 
 from sceptre.stack import Stack
@@ -59,23 +60,38 @@ def test_initiate_stack(self):
  def test_repr(self):
  assert self.stack.__repr__() == \
  "sceptre.stack.Stack(" \
- "name='sentinel.stack_name', " \
- "project_code='sentinel.project_code', " \
- "template_path='sentinel.template_path', " \
- "region='sentinel.region', " \
- "template_bucket_name='sentinel.template_bucket_name', "\
- "template_key_prefix='sentinel.template_key_prefix', "\
- "required_version='sentinel.required_version', "\
- "profile='sentinel.profile', " \
- "sceptre_user_data='sentinel.sceptre_user_data', " \
- "parameters='{'key1': 'val1'}', "\
- "hooks='{}', s3_details='None', " \
- "dependencies='sentinel.dependencies', "\
- "role_arn='sentinel.role_arn', " \
- "protected='False', tags='{'tag1': 'val1'}', " \
- "external_name='sentinel.external_name', " \
- "notifications='[sentinel.notification]', " \
- "on_failure='sentinel.on_failure', " \
- "stack_timeout='sentinel.stack_timeout', " \
- "stack_group_config='{}'" \
+ "name=sentinel.stack_name, " \
+ "project_code=sentinel.project_code, " \
+ "template_path=sentinel.template_path, " \
+ "region=sentinel.region, " \
+ "template_bucket_name=sentinel.template_bucket_name, "\
+ "template_key_prefix=sentinel.template_key_prefix, "\
+ "required_version=sentinel.required_version, "\
+ "profile=sentinel.profile, " \
+ "sceptre_user_data=sentinel.sceptre_user_data, " \
+ "parameters={'key1': 'val1'}, "\
+ "hooks={}, "\
+ "s3_details=None, " \
+ "dependencies=sentinel.dependencies, "\
+ "role_arn=sentinel.role_arn, "\
+ "protected=False, "\
+ "tags={'tag1': 'val1'}, "\
+ "external_name=sentinel.external_name, " \
+ "notifications=[sentinel.notification], " \
+ "on_failure=sentinel.on_failure, " \
+ "stack_timeout=sentinel.stack_timeout, " \
+ "stack_group_config={}" \
  ")"
+
+ def test_repr_can_eval_correctly(self):
+ sceptre = importlib.import_module('sceptre')
+ mock = importlib.import_module('mock')
+ evaluated_stack = eval(
+ repr(self.stack),
+ {
+ 'sceptre': sceptre,
+ 'sentinel': mock.mock.sentinel
+ }
+ )
+ assert isinstance(evaluated_stack, Stack)
+ assert evaluated_stack.__eq__(self.stack)