Handle association set ends with same entity sets

In the metadata document, it is allowed to declare same Entity Sets in
different ends of one Association Set. Therefore, we cannot utilize
dictionary to store such ends (values can be overwritten).

In this commit, there is added a new class AssociationSetEndRole which
represents one end within the Association Set. End roles are stored in
a list, in the same manner like end roles in the Association. Also,
each end now contains a reference to a corresponding entity set.

Author: lubosmj

pyodata/v2/model.py

@@ -898,17 +898,19 @@ def from_etree(schema_nodes):
                         'Association {} does not exist in namespace {}'
                         .format(assoc_set.association_type_name, assoc_set.association_type_namespace))
 
-                for key, value in list(assoc_set.end_roles.items()):
-                    # Check if entity set exists in current scheme
+                for end in assoc_set.end_roles:
+                    # Check if an entity set exists in the current scheme
+                    # and add a reference to the corresponding entity set
                     try:
-                        schema.entity_set(key, namespace)
+                        entity_set = schema.entity_set(end.entity_set_name, namespace)
+                        end.entity_set = entity_set
                     except KeyError:
                         raise PyODataModelError('EntitySet {} does not exist in Schema Namespace {}'
-                                                .format(key, namespace))
+                                                .format(end.entity_set_name, namespace))
                     # Check if role is defined in Association
-                    if assoc_set.association_type.end_by_role(value) is None:
+                    if assoc_set.association_type.end_by_role(end.role) is None:
                         raise PyODataModelError('Role {} is not defined in association {}'
-                                                .format(value, assoc_set.association_type_name))
+                                                .format(end.role, assoc_set.association_type_name))
 
                 decl.association_sets[assoc_set.name] = assoc_set
 
@@ -1556,6 +1558,46 @@ def from_etree(association_node):
         return association
 
 
+class AssociationSetEndRole:
+    def __init__(self, role, entity_set_name):
+        self._role = role
+        self._entity_set_name = entity_set_name
+        self._entity_set = None
+
+    def __repr__(self):
+        return "{0}({1})".format(self.__class__.__name__, self.role)
+
+    @property
+    def role(self):
+        return self._role
+
+    @property
+    def entity_set_name(self):
+        return self._entity_set_name
+
+    @property
+    def entity_set(self):
+        return self._entity_set
+
+    @entity_set.setter
+    def entity_set(self, value):
+        if self._entity_set:
+            raise PyODataModelError('Cannot replace {0} of {1} to {2}'.format(self._entity_set, self, value))
+
+        if value.name != self._entity_set_name:
+            raise PyODataModelError(
+                'Assigned entity set {0} differentiates from the declared {1}'.format(value, self._entity_set_name))
+
+        self._entity_set = value
+
+    @staticmethod
+    def from_etree(end_node):
+        role = end_node.get('Role')
+        entity_set = end_node.get('EntitySet')
+
+        return AssociationSetEndRole(role, entity_set)
+
+
 class AssociationSet:
     def __init__(self, name, association_type_name, association_type_namespace, end_roles):
         self._name = name
@@ -1587,6 +1629,18 @@ def association_type_namespace(self):
     def end_roles(self):
         return self._end_roles
 
+    def end_by_role(self, end_role):
+        try:
+            return next((end for end in self._end_roles if end.role == end_role))
+        except StopIteration:
+            raise KeyError('Association set {} has no End with Role {}'.format(self._name, end_role))
+
+    def end_by_entity_set(self, entity_set):
+        try:
+            return next((end for end in self._end_roles if end.entity_set_name == entity_set))
+        except StopIteration:
+            raise KeyError('Association set {} has no End with Entity Set {}'.format(self._name, entity_set))
+
     @association_type.setter
     def association_type(self, value):
         if self._association_type is not None:
@@ -1595,7 +1649,7 @@ def association_type(self, value):
 
     @staticmethod
     def from_etree(association_set_node):
-        end_roles = {}
+        end_roles = []
         name = association_set_node.get('Name')
         scheme_namespace, association_type_name = association_set_node.get('Association').split('.', 1)
 
@@ -1604,9 +1658,7 @@ def from_etree(association_set_node):
             raise PyODataModelError('Association {} cannot have more than 2 end roles'.format(name))
 
         for end_role in end_roles_list:
-            entity_set = end_role.get('EntitySet')
-            role = end_role.get('Role')
-            end_roles[entity_set] = role
+            end_roles.append(AssociationSetEndRole.from_etree(end_role))
 
         return AssociationSet(name, association_type_name, scheme_namespace, end_roles)
 

pyodata/v2/service.py

@@ -789,9 +789,9 @@ def nav(self, nav_property):
             association_info.namespace)
 
         navigation_entity_set = None
-        for entity_set in association_set.end_roles:
-            if association_set.end_roles[entity_set] == navigation_property.to_role.role:
-                navigation_entity_set = self._service.schema.entity_set(entity_set, association_info.namespace)
+        for end in association_set.end_roles:
+            if association_set.end_by_entity_set(end.entity_set_name).role == navigation_property.to_role.role:
+                navigation_entity_set = self._service.schema.entity_set(end.entity_set_name, association_info.namespace)
 
         if not navigation_entity_set:
             raise PyODataException('No association set for role {}'.format(navigation_property.to_role))
@@ -997,12 +997,12 @@ def nav(self, nav_property, key):
             association_info.name)
 
         navigation_entity_set = None
-        for entity_set in association_set.end_roles:
-            if association_set.end_roles[entity_set] == navigation_property.to_role.role:
-                navigation_entity_set = self._service.schema.entity_set(entity_set)
+        for end in association_set.end_roles:
+            if association_set.end_by_entity_set(end.entity_set_name).role == navigation_property.to_role.role:
+                navigation_entity_set = self._service.schema.entity_set(end.entity_set_name)
 
         if not navigation_entity_set:
-            raise PyODataException('No association set for role {}'.format(navigation_property.to_role))
+            raise PyODataException('No association set for role {} {}'.format(navigation_property.to_role, association_set.end_roles))
 
         roles = navigation_property.association.end_roles
         if all((role.multiplicity != model.EndRole.MULTIPLICITY_ZERO_OR_MORE for role in roles)):

tests/conftest.py

@@ -128,7 +128,6 @@ def metadata():
              </Dependent>
             </ReferentialConstraint>
            </Association>
-
            <Association Name="CustomerOrders">
             <End Role="CustomerRole" Type="EXAMPLE_SRV.Customer" Multiplicity="1"/>
             <End Role="OrdersRole" Type="EXAMPLE_SRV.Order" Multiplicity="*"/>
@@ -141,7 +140,10 @@ def metadata():
              </Dependent>
             </ReferentialConstraint>
            </Association>
-
+           <Association Name="toSelfMaster" sap:content-version="1">
+            <End Type="EXAMPLE_SRV.MasterEntity" Multiplicity="1" Role="FromRole_toSelfMaster" />
+            <End Type="EXAMPLE_SRV.MasterEntity" Multiplicity="0..1" Role="ToRole_toSelfMaster" />
+           </Association>
            <EntityContainer Name="EXAMPLE_SRV" m:IsDefaultEntityContainer="true" sap:supported-formats="atom json xlsx">
             <EntitySet Name="MasterEntities" EntityType="EXAMPLE_SRV.MasterEntity" sap:label="Master entities" sap:creatable="false" sap:updatable="false" sap:deletable="false" sap:searchable="true" sap:content-version="1"/>
             <EntitySet Name="DataValueHelp" EntityType="EXAMPLE_SRV.DataEntity" sap:creatable="false" sap:updatable="false" sap:deletable="false" sap:searchable="true" sap:content-version="1"/>
@@ -161,6 +163,10 @@ def metadata():
               <End EntitySet="Cars" Role="FromRole_toCarIDPic" />
               <End EntitySet="CarIDPics" Role="ToRole_toCarIDPic" />
             </AssociationSet>
+            <AssociationSet Name="toSelfMasterSet" Association="EXAMPLE_SRV.toSelfMaster" sap:creatable="false" sap:updatable="false" sap:deletable="false" sap:content-version="1">
+              <End EntitySet="MasterEntities" Role="FromRole_toSelfMaster" />
+              <End EntitySet="MasterEntities" Role="ToRole_toSelfMaster" />
+            </AssociationSet>
            </EntityContainer>
            <Annotations xmlns="http://docs.oasis-open.org/odata/ns/edm" Target="EXAMPLE_SRV.MasterEntity/Data">
             <Annotation Term="com.sap.vocabularies.Common.v1.ValueList">

tests/test_model_v2.py

@@ -3,8 +3,8 @@
 
 from datetime import datetime
 import pytest
-import pyodata.v2.model
-from pyodata.v2.model import Edmx, Typ, StructTypeProperty, Types, EntityType, EdmStructTypeSerializer
+from pyodata.v2.model import Edmx, Typ, StructTypeProperty, Types, EntityType, EdmStructTypeSerializer,\
+    Association, AssociationSet, EndRole, AssociationSetEndRole
 from pyodata.exceptions import PyODataException, PyODataModelError
 
 
@@ -163,10 +163,13 @@ def test_schema_entity_sets(schema):
 def test_edmx_associations(schema):
     """Test parsing of associations and association sets"""
 
-    assert set((association.name for association in schema.associations)) == {'toCarIDPic',
-                                                                              'toDataEntity',
-                                                                              'CustomerOrders',
-                                                                              'AssociationEmployeeAddress'}
+    assert set((association.name for association in schema.associations)) == {
+        'toCarIDPic',
+        'toDataEntity',
+        'CustomerOrders',
+        'AssociationEmployeeAddress',
+        'toSelfMaster'
+    }
 
     association = schema.association('toDataEntity')
     assert str(association) == 'Association(toDataEntity)'
@@ -187,14 +190,31 @@ def test_edmx_associations(schema):
     assert dependent_role.name == 'ToRole_toDataEntity'
     assert dependent_role.property_names == ['Name']
 
-    assert set((association_set.name for association_set in schema.association_sets)) == {'toDataEntitySet',
-                                                                                          'AssociationEmployeeAddress_AssocSet',
-                                                                                          'CustomerOrder_AssocSet',
-                                                                                          'toCarIDPicSet'}
+    assert set((association_set.name for association_set in schema.association_sets)) == {
+        'toDataEntitySet',
+        'AssociationEmployeeAddress_AssocSet',
+        'CustomerOrder_AssocSet',
+        'toCarIDPicSet',
+        'toSelfMasterSet'
+    }
+
     association_set = schema.association_set('toDataEntitySet')
     assert str(association_set) == 'AssociationSet(toDataEntitySet)'
     assert association_set.association_type.name == 'toDataEntity'
-    assert association_set.end_roles == {'DataValueHelp': 'ToRole_toDataEntity', 'MasterEntities': 'FromRole_toDataEntity'}
+
+    # check associated references to entity sets
+    association_set = schema.association_set('toDataEntitySet')
+    entity_sets = {end.entity_set.name for end in association_set.end_roles}
+    assert entity_sets == {'MasterEntities', 'DataValueHelp'}
+
+    end_roles = {(end.entity_set_name, end.role) for end in association_set.end_roles}
+    assert end_roles == {('DataValueHelp', 'ToRole_toDataEntity'), ('MasterEntities', 'FromRole_toDataEntity')}
+
+    # same entity sets in different ends
+    association_set = schema.association_set('toSelfMasterSet')
+    assert str(association_set) == 'AssociationSet(toSelfMasterSet)'
+    end_roles = {(end.entity_set_name, end.role) for end in association_set.end_roles}
+    assert end_roles == {('MasterEntities', 'ToRole_toSelfMaster'), ('MasterEntities', 'FromRole_toSelfMaster')}
 
     # with namespace
     association_set = schema.association_set_by_association('CustomerOrders', namespace='EXAMPLE_SRV_SETS')
@@ -686,10 +706,10 @@ def test_edmx_entity_sets(schema):
 def test_edmx_association_end_by_role():
     """Test the method end_by_role of the class Association"""
 
-    end_from = pyodata.v2.model.EndRole(None, pyodata.v2.model.EndRole.MULTIPLICITY_ONE, 'From')
-    end_to = pyodata.v2.model.EndRole(None, pyodata.v2.model.EndRole.MULTIPLICITY_ZERO_OR_ONE, 'To')
+    end_from = EndRole(None, EndRole.MULTIPLICITY_ONE, 'From')
+    end_to = EndRole(None, EndRole.MULTIPLICITY_ZERO_OR_ONE, 'To')
 
-    association = pyodata.v2.model.Association('FooBar')
+    association = Association('FooBar')
     association.end_roles.append(end_from)
     association.end_roles.append(end_to)
 
@@ -699,3 +719,27 @@ def test_edmx_association_end_by_role():
     with pytest.raises(KeyError) as typ_ex_info:
         association.end_by_role('Blah')
     assert typ_ex_info.value.args[0] == 'Association FooBar has no End with Role Blah'
+
+
+def test_edmx_association_set_end_by_role():
+    """Test the method end_by_role of the class AssociationSet"""
+
+    end_from = AssociationSetEndRole('From', 'EntitySet')
+    end_to = AssociationSetEndRole('To', 'EntitySet')
+
+    association_set = AssociationSet('FooBar', 'Foo', 'EXAMPLE_SRV', [end_from, end_to])
+
+    assert association_set.end_by_role(end_from.role) == end_from
+    assert association_set.end_by_role(end_to.role) == end_to
+
+
+def test_edmx_association_set_end_by_entity_set():
+    """Test the method end_by_entity_set of the class AssociationSet"""
+
+    end_from = AssociationSetEndRole('From', 'EntitySet1')
+    end_to = AssociationSetEndRole('To', 'EntitySet2')
+
+    association_set = AssociationSet('FooBar', 'Foo', 'EXAMPLE_SRV', [end_from, end_to])
+
+    assert association_set.end_by_entity_set(end_from.entity_set_name) == end_from
+    assert association_set.end_by_entity_set(end_to.entity_set_name) == end_to