Improve StackValidationFailed resp param_groups

Use StackValidationFailed exception's parameters
error and path in parameter groups validation for
fuller error message: which error has been raised,
where this error has been raised and why.
This patch relies on topic [1].

[1]: https://review.openstack.org/#/q/status:merged+project:openstack/heat+branch:master+topic:improve-validation-error,n,z
Change-Id: I2b1b096b314b52b2a51d09c47c46b902e6647c59

heat/engine/parameter_groups.py

@@ -45,34 +45,46 @@ class ParameterGroups(object):
         LOG.debug(self.parameter_names)
         if self.parameter_groups:
             if not isinstance(self.parameter_groups, list):
-                raise exception.StackValidationFailed(message=_(
-                    'The %s should be a list.') % PARAMETER_GROUPS)
+                raise exception.StackValidationFailed(
+                    error=_('Parameter Groups error'),
+                    path=[PARAMETER_GROUPS],
+                    message=_('The %s should be a list.') % PARAMETER_GROUPS)
 
             # Loop through groups and validate parameters
             grouped_parameters = []
             for group in self.parameter_groups:
                 parameters = group.get(PARAMETERS)
                 if parameters is None:
-                    raise exception.StackValidationFailed(message=_(
-                        'The %s must be provided for '
-                        'each parameter group.') % PARAMETERS)
+                    raise exception.StackValidationFailed(
+                        error=_('Parameter Groups error'),
+                        path=[PARAMETER_GROUPS, group.get('label')],
+                        message=_('The %s must be provided for '
+                                  'each parameter group.') % PARAMETERS)
 
                 if not isinstance(parameters, list):
-                    raise exception.StackValidationFailed(message=_(
-                        'The %s of parameter group '
-                        'should be a list.') % PARAMETERS)
+                    raise exception.StackValidationFailed(
+                        error=_('Parameter Groups error'),
+                        path=[PARAMETER_GROUPS, group.get('label')],
+                        message=_('The %s of parameter group '
+                                  'should be a list.') % PARAMETERS)
 
                 for param in parameters:
                     # Check if param has been added to a previous group
                     if param in grouped_parameters:
-                        raise exception.StackValidationFailed(message=_(
-                            'The %s parameter must be assigned to one '
-                            'parameter group only.') % param)
+                        raise exception.StackValidationFailed(
+                            error=_('Parameter Groups error'),
+                            path=[PARAMETER_GROUPS, group.get('label')],
+                            message=_(
+                                'The %s parameter must be assigned to one '
+                                'parameter group only.') % param)
                     else:
                         grouped_parameters.append(param)
 
                     # Check that grouped parameter references a valid Parameter
                     if param not in self.parameter_names:
-                        raise exception.StackValidationFailed(message=_(
-                            'The grouped parameter %s does not reference '
-                            'a valid parameter.') % param)
+                        raise exception.StackValidationFailed(
+                            error=_('Parameter Groups error'),
+                            path=[PARAMETER_GROUPS, group.get('label')],
+                            message=_(
+                                'The grouped parameter %s does not reference '
+                                'a valid parameter.') % param)

heat/tests/test_validate.py

@@ -1407,8 +1407,11 @@ class validateTest(common.HeatTestCase):
         exc = self.assertRaises(exception.StackValidationFailed,
                                 stack.validate)
 
-        self.assertEqual(_('The InstanceType parameter must be assigned to '
-                         'one parameter group only.'), six.text_type(exc))
+        self.assertEqual(_('Parameter Groups error : '
+                           'parameter_groups.Database '
+                           'Group: The InstanceType parameter must be '
+                           'assigned to one parameter group only.'),
+                         six.text_type(exc))
 
     def test_validate_invalid_parameter_in_group(self):
         t = template_format.parse(test_template_invalid_parameter_name)
@@ -1422,8 +1425,10 @@ class validateTest(common.HeatTestCase):
         exc = self.assertRaises(exception.StackValidationFailed,
                                 stack.validate)
 
-        self.assertEqual(_('The grouped parameter SomethingNotHere does not '
-                         'reference a valid parameter.'),
+        self.assertEqual(_('Parameter Groups error : '
+                           'parameter_groups.Database Group: The grouped '
+                           'parameter SomethingNotHere does not '
+                           'reference a valid parameter.'),
                          six.text_type(exc))
 
     def test_validate_no_parameters_in_group(self):
@@ -1433,7 +1438,8 @@ class validateTest(common.HeatTestCase):
         exc = self.assertRaises(exception.StackValidationFailed,
                                 stack.validate)
 
-        self.assertEqual(_('The parameters must be provided for each '
+        self.assertEqual(_('Parameter Groups error : parameter_groups.Server '
+                           'Group: The parameters must be provided for each '
                            'parameter group.'), six.text_type(exc))
 
     def test_validate_parameter_groups_not_list(self):
@@ -1443,7 +1449,8 @@ class validateTest(common.HeatTestCase):
         exc = self.assertRaises(exception.StackValidationFailed,
                                 stack.validate)
 
-        self.assertEqual(_('The parameter_groups should be '
+        self.assertEqual(_('Parameter Groups error : parameter_groups: '
+                           'The parameter_groups should be '
                            'a list.'), six.text_type(exc))
 
     def test_validate_parameters_not_list(self):
@@ -1453,7 +1460,9 @@ class validateTest(common.HeatTestCase):
         exc = self.assertRaises(exception.StackValidationFailed,
                                 stack.validate)
 
-        self.assertEqual(_('The parameters of parameter group should be '
+        self.assertEqual(_('Parameter Groups error : '
+                           'parameter_groups.Server Group: '
+                           'The parameters of parameter group should be '
                            'a list.'), six.text_type(exc))
 
     def test_validate_allowed_values_integer(self):