How to use the runway.cfngin.stack.Stack function in runway

def test_execute_plan_no_persist(self):
        """Test execute plan with no persistent graph."""
        context = Context(config=self.config)
        context.put_persistent_graph = mock.MagicMock()
        vpc = Stack(
            definition=generate_definition('vpc', 1),
            context=context)
        bastion = Stack(
            definition=generate_definition('bastion', 1, requires=[vpc.name]),
            context=context)

        calls = []

        def _launch_stack(stack, status=None):
            calls.append(stack.fqn)
            return COMPLETE

        graph = Graph.from_steps([Step(vpc, _launch_stack),
                                  Step(bastion, _launch_stack)])
        plan = Plan(description="Test", graph=graph, context=context)

        plan.execute(walk)

        self.assertEqual(calls, ['namespace-vpc.1', 'namespace-bastion.1'])

def test_execute_plan_cancelled(self):
        """Test execute plan cancelled."""
        vpc = Stack(
            definition=generate_definition('vpc', 1),
            context=self.context)
        bastion = Stack(
            definition=generate_definition('bastion', 1, requires=[vpc.name]),
            context=self.context)

        calls = []

        def fn(stack, status=None):
            calls.append(stack.fqn)
            if stack.fqn == vpc_step.name:
                raise CancelExecution
            return COMPLETE

        vpc_step = Step(vpc, fn)
        bastion_step = Step(bastion, fn)

def test_execute_plan(self):
        """Test execute plan."""
        context = Context(config=self.config)
        context.put_persistent_graph = mock.MagicMock()
        vpc = Stack(
            definition=generate_definition('vpc', 1),
            context=context)
        bastion = Stack(
            definition=generate_definition('bastion', 1, requires=[vpc.name]),
            context=context)
        removed = Stack(
            definition=generate_definition('removed', 1, requires=[]),
            context=context)
        context._persistent_graph = Graph.from_steps([removed])

        calls = []

        def _launch_stack(stack, status=None):
            calls.append(stack.fqn)
            return COMPLETE

        def _destroy_stack(stack, status=None):
            calls.append(stack.fqn)
            return COMPLETE

def test_execute_plan_failed(self):
        """Test execute plan failed."""
        vpc = Stack(
            definition=generate_definition('vpc', 1),
            context=self.context)
        bastion = Stack(
            definition=generate_definition('bastion', 1, requires=[vpc.name]),
            context=self.context)
        db = Stack(
            definition=generate_definition('db', 1),
            context=self.context)

        calls = []

        def fn(stack, status=None):
            calls.append(stack.fqn)
            if stack.name == vpc_step.name:
                return FAILED
            return COMPLETE

        vpc_step = Step(vpc, fn)
        bastion_step = Step(bastion, fn)
        db_step = Step(db, fn)

        graph = Graph.from_steps([vpc_step, bastion_step, db_step])

def test_build_graph_cyclic_dependencies(self):
        """Test build graph cyclic dependencies."""
        vpc = Stack(
            definition=generate_definition(
                'vpc', 1),
            context=self.context)
        db = Stack(
            definition=generate_definition(
                'db', 1, requires=['app.1']),
            context=self.context)
        app = Stack(
            definition=generate_definition(
                'app', 1, requires=['db.1']),
            context=self.context)

        with self.assertRaises(GraphError) as expected:
            Graph.from_steps([Step(vpc, None), Step(db, None), Step(app, None)])
        message = ("Error detected when adding 'db.1' "
                   "as a dependency of 'app.1': graph is "
                   "not acyclic")
        self.assertEqual(str(expected.exception), message)

def test_plan_reverse(self):
        """Test plan reverse."""
        vpc = Stack(
            definition=generate_definition('vpc', 1),
            context=self.context)
        bastion = Stack(
            definition=generate_definition('bastion', 1, requires=[vpc.name]),
            context=self.context)
        graph = Graph.from_steps([Step(vpc, fn=None), Step(bastion, fn=None)])
        plan = Plan(description="Test", graph=graph, reverse=True)

        # order is different between python2/3 so can't compare dicts
        result_graph_dict = plan.graph.to_dict()
        self.assertEqual(set(), result_graph_dict.get('bastion.1'))
        self.assertEqual(set(['bastion.1']), result_graph_dict.get('vpc.1'))

def test_execute_plan_filtered(self):
        """Test execute plan filtered."""
        vpc = Stack(
            definition=generate_definition('vpc', 1),
            context=self.context)
        db = Stack(
            definition=generate_definition('db', 1, requires=[vpc.name]),
            context=self.context)
        app = Stack(
            definition=generate_definition('app', 1, requires=[db.name]),
            context=self.context)

        calls = []

        def fn(stack, status=None):
            calls.append(stack.fqn)
            return COMPLETE

        context = mock.MagicMock()

def test_execute_plan(self):
        """Test execute plan."""
        context = Context(config=self.config)
        context.put_persistent_graph = mock.MagicMock()
        vpc = Stack(
            definition=generate_definition('vpc', 1),
            context=context)
        bastion = Stack(
            definition=generate_definition('bastion', 1, requires=[vpc.name]),
            context=context)
        removed = Stack(
            definition=generate_definition('removed', 1, requires=[]),
            context=context)
        context._persistent_graph = Graph.from_steps([removed])

        calls = []

        def _launch_stack(stack, status=None):
            calls.append(stack.fqn)
            return COMPLETE

        def _destroy_stack(stack, status=None):
            calls.append(stack.fqn)
            return COMPLETE

        graph = Graph.from_steps([Step(removed, _destroy_stack),
                                  Step(vpc, _launch_stack),

def test_execute_plan_filtered(self):
        """Test execute plan filtered."""
        vpc = Stack(
            definition=generate_definition('vpc', 1),
            context=self.context)
        db = Stack(
            definition=generate_definition('db', 1, requires=[vpc.name]),
            context=self.context)
        app = Stack(
            definition=generate_definition('app', 1, requires=[db.name]),
            context=self.context)

        calls = []

        def fn(stack, status=None):
            calls.append(stack.fqn)
            return COMPLETE

        context = mock.MagicMock()
        context.persistent_graph_locked = False
        context.stack_names = ['db.1']
        graph = Graph.from_steps([Step(vpc, fn), Step(db, fn), Step(app, fn)])

This function will be ran multiple times until the step
                is "done".
            watch_func (Callable): an optional function that will be
                called to "tail" the step action.

        Returns:
            :class:`Step`

        """
        # pylint: disable=import-outside-toplevel
        from runway.cfngin.config import Stack as StackConfig
        from runway.cfngin.stack import Stack

        stack_def = StackConfig({'name': stack_name,
                                 'requires': requires or []})
        stack = Stack(stack_def, context)
        return cls(stack, fn=fn, watch_func=watch_func)