Added occurrences of requirements validation

Added validation check for occurrences property value of requirements.
Included unit testcases

Change-Id: I6e4fc6769464a3973db5b778d0d318ab7525510e
Partially Implements: blueprint tosca-requirement-changes

toscaparser/nodetemplate.py

@@ -13,8 +13,10 @@
 
 import logging
 
+from toscaparser.common.exception import InvalidPropertyValueError
 from toscaparser.common.exception import TypeMismatchError
 from toscaparser.common.exception import UnknownFieldError
+from toscaparser.dataentity import DataEntity
 from toscaparser.elements.interfaces import CONFIGURE
 from toscaparser.elements.interfaces import CONFIGURE_SHORTNAME
 from toscaparser.elements.interfaces import InterfacesDef
@@ -180,9 +182,28 @@ class NodeTemplate(EntityTemplate):
                 for r1, value in req.items():
                     if isinstance(value, dict):
                         self._validate_requirements_keys(value)
+                        self._validate_requirements_properties(value)
                         allowed_reqs.append(r1)
                 self._common_validate_field(req, allowed_reqs, 'Requirements')
 
+    def _validate_requirements_properties(self, requirements):
+        # TODO(anyone): Only occurences property of the requirements is
+        # validated here. Validation of other requirement properties are being
+        # validated in different files. Better to keep all the requirements
+        # properties validation here.
+        for key, value in requirements.items():
+            if key == 'occurrences':
+                self._validate_occurrences(value)
+                break
+
+    def _validate_occurrences(self, occurrences):
+        DataEntity.validate_datatype('list', occurrences)
+        for value in occurrences:
+            DataEntity.validate_datatype('integer', value)
+        if len(occurrences) != 2 or not (0 <= occurrences[0] <= occurrences[1]) \
+            or occurrences[1] == 0:
+            raise InvalidPropertyValueError(what=(occurrences))
+
     def _validate_requirements_keys(self, requirement):
         for key in requirement.keys():
             if key not in self.REQUIREMENTS_SECTION:

toscaparser/tests/test_toscatplvalidation.py

@@ -450,6 +450,33 @@ class ToscaTemplateValidationTest(TestCase):
                                                 exception.UnknownFieldError,
                                                 expectedmessage)
 
+    def test_node_template_requirements_with_wrong_occurrences_keyname(self):
+        """Incorrect node template requirements keyname
+
+        Node template requirements keyname 'occurrences' given as
+        'occurences'.
+        """
+        tpl_snippet = '''
+        node_templates:
+          mysql_database:
+            type: tosca.nodes.Database
+            requirements:
+              - host:
+                  node: mysql_dbms
+              - log_endpoint:
+                  node: logstash
+                  capability: log_endpoint
+                  relationship:
+                    type: tosca.relationships.ConnectsTo
+                  occurences: [0, UNBOUNDED]
+        '''
+        expectedmessage = ('Requirements of template mysql_database '
+                           'contain(s) unknown field: "occurences", refer'
+                           ' to the definition to verify valid values.')
+        self._single_node_template_content_test(tpl_snippet,
+                                                exception.UnknownFieldError,
+                                                expectedmessage)
+
     def test_node_template_requirements_with_multiple_wrong_keynames(self):
         """Node templates given with multiple wrong requirements keynames."""
         tpl_snippet = '''
@@ -494,6 +521,98 @@ class ToscaTemplateValidationTest(TestCase):
                                                 exception.UnknownFieldError,
                                                 expectedmessage)
 
+    def test_node_template_requirements_invalid_occurrences(self):
+        tpl_snippet = '''
+        node_templates:
+          server:
+            type: tosca.nodes.Compute
+            requirements:
+              - log_endpoint:
+                  capability: log_endpoint
+                  occurrences: [0, -1]
+        '''
+        expectedmessage = ('Value of property "[0, -1]" is invalid.')
+        self._single_node_template_content_test(
+            tpl_snippet,
+            exception.InvalidPropertyValueError,
+            expectedmessage)
+
+        tpl_snippet = '''
+        node_templates:
+          server:
+            type: tosca.nodes.Compute
+            requirements:
+              - log_endpoint:
+                  capability: log_endpoint
+                  occurrences: [a, w]
+        '''
+        expectedmessage = ('"a" is not an integer')
+        self._single_node_template_content_test(
+            tpl_snippet,
+            ValueError,
+            expectedmessage)
+
+        tpl_snippet = '''
+        node_templates:
+          server:
+            type: tosca.nodes.Compute
+            requirements:
+              - log_endpoint:
+                  capability: log_endpoint
+                  occurrences: -1
+        '''
+        expectedmessage = ('"-1" is not a list')
+        self._single_node_template_content_test(
+            tpl_snippet,
+            ValueError,
+            expectedmessage)
+
+        tpl_snippet = '''
+        node_templates:
+          server:
+            type: tosca.nodes.Compute
+            requirements:
+              - log_endpoint:
+                  capability: log_endpoint
+                  occurrences: [5, 1]
+        '''
+        expectedmessage = ('Value of property "[5, 1]" is invalid.')
+        self._single_node_template_content_test(
+            tpl_snippet,
+            exception.InvalidPropertyValueError,
+            expectedmessage)
+
+        tpl_snippet = '''
+        node_templates:
+          server:
+            type: tosca.nodes.Compute
+            requirements:
+              - log_endpoint:
+                  capability: log_endpoint
+                  occurrences: [0, 0]
+        '''
+        expectedmessage = ('Value of property "[0, 0]" is invalid.')
+        self._single_node_template_content_test(
+            tpl_snippet,
+            exception.InvalidPropertyValueError,
+            expectedmessage)
+
+    def test_node_template_requirements_valid_occurrences(self):
+        tpl_snippet = '''
+        node_templates:
+          server:
+            type: tosca.nodes.Compute
+            requirements:
+              - log_endpoint:
+                  capability: log_endpoint
+                  occurrences: [2, 2]
+        '''
+        expectedmessage = ''
+        self._single_node_template_content_test(
+            tpl_snippet,
+            None,
+            expectedmessage)
+
     def test_node_template_capabilities(self):
         tpl_snippet = '''
         node_templates: