Merge branch 'develop'v0.23.03

1 files changed, 0 insertions, 769 deletions

diff --git a/test/triple_store/test_sparql.py b/test/triple_store/test_sparql.py
deleted file mode 100644
index 8d98749..0000000
--- a/test/triple_store/test_sparql.py
+++ /dev/null
@@ -1,769 +0,0 @@
-"""
-
-Part of the bsfs test suite.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
-# imports
-import rdflib
-import unittest
-
-# bsie imports
-from bsfs import schema as _schema
-from bsfs.namespace import ns
-from bsfs.utils import errors, URI
-
-# objects to test
-from bsfs.triple_store.sparql import SparqlStore
-
-
-## code ##
-
-class TestSparqlStore(unittest.TestCase):
-    def setUp(self):
-        self.schema = _schema.Schema.from_string('''
-            prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
-            prefix xsd: <http://www.w3.org/2001/XMLSchema#>
-
-            prefix bsfs: <http://bsfs.ai/schema/>
-            prefix bse: <http://bsfs.ai/schema/Entity#>
-
-            bsfs:Entity rdfs:subClassOf bsfs:Node .
-            bsfs:Tag rdfs:subClassOf bsfs:Node .
-            bsfs:User rdfs:subClassOf bsfs:Node .
-            xsd:string rdfs:subClassOf bsfs:Literal .
-            xsd:integer rdfs:subClassOf bsfs:Literal .
-
-            # non-unique literal
-            bse:comment rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range xsd:string ;
-                bsfs:unique "false"^^xsd:boolean .
-
-            # unique literal
-            bse:filesize rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range xsd:integer ;
-                bsfs:unique "true"^^xsd:boolean .
-
-            # non-unique node
-            bse:tag rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range bsfs:Tag ;
-                bsfs:unique "false"^^xsd:boolean .
-
-            # unique node
-            bse:author rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range bsfs:User ;
-                bsfs:unique "true"^^xsd:boolean .
-
-            ''')
-
-    def test_essentials(self):
-        store = SparqlStore.Open()
-        # equality
-        self.assertEqual(store, store)
-        self.assertEqual(hash(store), hash(store))
-        self.assertNotEqual(store, SparqlStore.Open())
-        self.assertNotEqual(hash(store), hash(SparqlStore.Open()))
-        # string conversion
-        self.assertEqual(str(store), 'SparqlStore(uri=None)')
-        self.assertEqual(repr(store), 'SparqlStore(uri=None)')
-        # open
-        self.assertIsInstance(SparqlStore.Open(), SparqlStore)
-
-
-    def test__has_type(self):
-        # setup store
-        store = SparqlStore.Open()
-        store.schema = _schema.Schema.from_string('''
-            prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
-            prefix xsd: <http://www.w3.org/2001/XMLSchema#>
-            prefix bsfs: <http://bsfs.ai/schema/>
-
-            bsfs:Entity rdfs:subClassOf bsfs:Node .
-            bsfs:Document rdfs:subClassOf bsfs:Entity .
-            bsfs:Image rdfs:subClassOf bsfs:Entity .
-            bsfs:PDF rdfs:subClassOf bsfs:Document .
-
-            ''')
-        # add some instances
-        store.create(store.schema.node(ns.bsfs.Entity), {URI('http://example.com/me/entity#1234')})
-        store.create(store.schema.node(ns.bsfs.Document), {URI('http://example.com/me/document#1234')})
-        store.create(store.schema.node(ns.bsfs.Image), {URI('http://example.com/me/image#1234')})
-        store.create(store.schema.node(ns.bsfs.PDF), {URI('http://example.com/me/pdf#1234')})
-
-        # node_type must be in the schema
-        self.assertRaises(errors.ConsistencyError, store._has_type, URI('http://example.com/me/entity#1234'), store.schema.node(ns.bsfs.Node).get_child(ns.bsfs.invalid))
-
-        # returns False on inexistent nodes
-        self.assertFalse(store._has_type(URI('http://example.com/me/entity#4321'), store.schema.node(ns.bsfs.Entity)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/document#4321'), store.schema.node(ns.bsfs.Document)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/image#4321'), store.schema.node(ns.bsfs.Image)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/pdf#4321'), store.schema.node(ns.bsfs.PDF)))
-
-        # _has_type checks direct types
-        self.assertTrue(store._has_type(URI('http://example.com/me/entity#1234'), store.schema.node(ns.bsfs.Entity)))
-        self.assertTrue(store._has_type(URI('http://example.com/me/document#1234'), store.schema.node(ns.bsfs.Document)))
-        self.assertTrue(store._has_type(URI('http://example.com/me/image#1234'), store.schema.node(ns.bsfs.Image)))
-        self.assertTrue(store._has_type(URI('http://example.com/me/pdf#1234'), store.schema.node(ns.bsfs.PDF)))
-
-        # _has_type checks type hierarchy
-        self.assertFalse(store._has_type(URI('http://example.com/me/entity#1234'), store.schema.node(ns.bsfs.Document)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/entity#1234'), store.schema.node(ns.bsfs.Image)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/entity#1234'), store.schema.node(ns.bsfs.PDF)))
-
-        self.assertTrue(store._has_type(URI('http://example.com/me/document#1234'), store.schema.node(ns.bsfs.Entity)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/document#1234'), store.schema.node(ns.bsfs.Image)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/document#1234'), store.schema.node(ns.bsfs.PDF)))
-
-        self.assertTrue(store._has_type(URI('http://example.com/me/image#1234'), store.schema.node(ns.bsfs.Entity)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/image#1234'), store.schema.node(ns.bsfs.Document)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/image#1234'), store.schema.node(ns.bsfs.PDF)))
-
-        self.assertTrue(store._has_type(URI('http://example.com/me/pdf#1234'), store.schema.node(ns.bsfs.Entity)))
-        self.assertTrue(store._has_type(URI('http://example.com/me/pdf#1234'), store.schema.node(ns.bsfs.Document)))
-        self.assertFalse(store._has_type(URI('http://example.com/me/pdf#1234'), store.schema.node(ns.bsfs.Image)))
-
-
-    def test_schema(self):
-        # setup
-        store = SparqlStore.Open()
-        curr = self.schema
-        p_comment = curr.predicate(ns.bse.comment)
-        p_filesize = curr.predicate(ns.bse.filesize)
-        p_tag = curr.predicate(ns.bse.tag)
-        p_author = curr.predicate(ns.bse.author)
-
-        # migrate to an initial schema
-        store.schema = curr
-        # store has migrated
-        self.assertEqual(store.schema, curr)
-
-        # add some instances
-        ent_ids = {URI('http://example.com/me/entity#1234'), URI('http://example.com/me/entity#4321')}
-        tag_ids = {URI('http://example.com/me/tag#1234'), URI('http://example.com/me/tag#4321')}
-        store.create(curr.node(ns.bsfs.Entity), ent_ids)
-        store.create(curr.node(ns.bsfs.Tag), tag_ids)
-        store.create(curr.node(ns.bsfs.User), {URI('http://example.com/me')})
-        # add some triples
-        store.set(curr.node(ns.bsfs.Entity), ent_ids, p_comment, {'foo', 'bar'})
-        store.set(curr.node(ns.bsfs.Entity), ent_ids, p_filesize, {1234})
-        store.set(curr.node(ns.bsfs.Entity), ent_ids, p_tag,
-            {URI('http://example.com/me/tag#1234'), URI('http://example.com/me/tag#4321')})
-        store.set(curr.node(ns.bsfs.Entity), ent_ids, p_author,
-            {URI('http://example.com/me')})
-        # check instances
-        instances = {
-            # node instances
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/tag#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            (rdflib.URIRef('http://example.com/me/tag#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            (rdflib.URIRef('http://example.com/me'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.User)),
-            # comments
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foo', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_comment.uri), rdflib.Literal('bar', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foo', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_comment.uri), rdflib.Literal('bar', datatype=rdflib.XSD.string)),
-            # filesize
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            # tags
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            # author
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me')),
-            }
-        self.assertSetEqual(set(store._graph), instances)
-
-        # add some classes to the schema
-        curr = curr + _schema.Schema.from_string('''
-            prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
-            prefix xsd: <http://www.w3.org/2001/XMLSchema#>
-            prefix bsfs: <http://bsfs.ai/schema/>
-            prefix bse: <http://bsfs.ai/schema/Entity#>
-            prefix bst: <http://bsfs.ai/schema/Tag#>
-            prefix bsc: <http://bsfs.ai/schema/Collection#>
-
-            bsfs:Entity rdfs:subClassOf bsfs:Node .
-            bsfs:Tag rdfs:subClassOf bsfs:Node .
-            bsfs:Collection rdfs:subClassOf bsfs:Node .
-            xsd:boolean rdfs:subClassOf bsfs:Literal .
-
-            # literal
-            bse:shared rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range xsd:boolean ;
-                bsfs:unique "true"^^xsd:boolean .
-
-            # node
-            bse:partOf rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range bsfs:Collection ;
-                bsfs:unique "false"^^xsd:boolean .
-
-            # predicates across auxiliary node classes
-            bst:usedIn rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Tag ;
-                rdfs:range bsfs:Collection ;
-                bsfs:unique "false"^^xsd:boolean .
-
-            bsc:tag rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Collection ;
-                rdfs:range bsfs:Tag ;
-                bsfs:unique "false"^^xsd:boolean .
-
-            bst:principal rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Tag ;
-                rdfs:range bsfs:Node ;
-                bsfs:unique "true"^^xsd:boolean .
-
-            ''')
-        # store migrated to the new schema
-        store.schema = curr
-        self.assertEqual(store.schema, curr)
-        # instances have not changed
-        self.assertSetEqual(set(store._graph), instances)
-        # add some instances of the new classes
-        p_partOf = curr.predicate(ns.bse.partOf)
-        p_shared = curr.predicate(ns.bse.shared)
-        p_usedIn = curr.predicate('http://bsfs.ai/schema/Tag#usedIn')
-        p_ctag = curr.predicate('http://bsfs.ai/schema/Collection#tag')
-        p_principal = curr.predicate('http://bsfs.ai/schema/Tag#principal')
-        store.create(curr.node(ns.bsfs.Collection), {URI('http://example.com/me/collection#1234'), URI('http://example.com/me/collection#4321')})
-        # add some more triples
-        store.set(curr.node(ns.bsfs.Entity), ent_ids, p_shared, {True})
-        store.set(curr.node(ns.bsfs.Entity), ent_ids, p_partOf,
-            {URI('http://example.com/me/collection#1234'), URI('http://example.com/me/collection#4321')})
-        store.set(curr.node(ns.bsfs.Tag), {URI('http://example.com/me/tag#1234')}, p_usedIn,
-            {URI('http://example.com/me/collection#1234')})
-        store.set(curr.node(ns.bsfs.Collection), {URI('http://example.com/me/collection#4321')}, p_ctag,
-            {URI('http://example.com/me/tag#1234'), URI('http://example.com/me/tag#4321')})
-        store.set(curr.node(ns.bsfs.Tag), {URI('http://example.com/me/tag#1234')}, p_principal,
-            {URI('http://example.com/me/collection#1234')})
-        # new instances are now in the graph
-        self.assertSetEqual(set(store._graph), instances | {
-            # collections
-            (rdflib.URIRef('http://example.com/me/collection#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Collection)),
-            (rdflib.URIRef('http://example.com/me/collection#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Collection)),
-            # partOf
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_partOf.uri), rdflib.URIRef('http://example.com/me/collection#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_partOf.uri), rdflib.URIRef('http://example.com/me/collection#4321')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_partOf.uri), rdflib.URIRef('http://example.com/me/collection#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_partOf.uri), rdflib.URIRef('http://example.com/me/collection#4321')),
-            # shared
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_shared.uri), rdflib.Literal('true', datatype=rdflib.XSD.boolean)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_shared.uri), rdflib.Literal('true', datatype=rdflib.XSD.boolean)),
-            # auxiliary node connections
-            (rdflib.URIRef('http://example.com/me/tag#1234'), rdflib.URIRef(p_usedIn.uri), rdflib.URIRef('http://example.com/me/collection#1234')),
-            (rdflib.URIRef('http://example.com/me/tag#1234'), rdflib.URIRef(p_principal.uri), rdflib.URIRef('http://example.com/me/collection#1234')),
-            (rdflib.URIRef('http://example.com/me/collection#4321'), rdflib.URIRef(p_ctag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/collection#4321'), rdflib.URIRef(p_ctag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            })
-
-
-        # remove some classes from the schema
-        curr = _schema.Schema.from_string('''
-            prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
-            prefix xsd: <http://www.w3.org/2001/XMLSchema#>
-            prefix bsfs: <http://bsfs.ai/schema/>
-            prefix bse: <http://bsfs.ai/schema/Entity#>
-            prefix bst: <http://bsfs.ai/schema/Tag#>
-
-            bsfs:Entity rdfs:subClassOf bsfs:Node .
-            bsfs:Tag rdfs:subClassOf bsfs:Node .
-            bsfs:User rdfs:subClassOf bsfs:Node .
-
-            xsd:boolean rdfs:subClassOf bsfs:Literal .
-            xsd:integer rdfs:subClassOf bsfs:Literal .
-
-            bse:filesize rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range xsd:integer ;
-                bsfs:unique "true"^^xsd:boolean .
-
-            bse:tag rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range bsfs:Tag ;
-                bsfs:unique "false"^^xsd:boolean .
-
-            bse:shared rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range xsd:boolean ;
-                bsfs:unique "true"^^xsd:boolean .
-
-            bst:principal rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Tag ;
-                rdfs:range bsfs:Node ;
-                bsfs:unique "true"^^xsd:boolean .
-
-            # removed: bsfs:Collection
-            # removed: xsd:string
-            # removed: bse:comment (bsfs:Entity -> xsd:string)
-            # removed: bse:partOf (bsfs:Entity -> bsfs:Collection)
-            # removed: bse:author (bsfs:entity -> bsfs:User)
-            # removed: bst:usedIn (bsfs:Tag -> bsfs:Collection)
-            # removed: bsc:tag (bsfs:Collection -> bsfs:Tag)
-
-            ''')
-        # store migrated to the new schema
-        store.schema = curr
-        self.assertEqual(store.schema, curr)
-        # instances of old classes were removed
-        self.assertSetEqual(set(store._graph), {
-            # node instances
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/tag#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            (rdflib.URIRef('http://example.com/me/tag#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            (rdflib.URIRef('http://example.com/me'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.User)),
-            # filesize
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            # tags
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            # shared
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_shared.uri), rdflib.Literal('true', datatype=rdflib.XSD.boolean)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_shared.uri), rdflib.Literal('true', datatype=rdflib.XSD.boolean)),
-            })
-
-        # can only assign schema instances
-        self.assertRaises(TypeError, setattr, store, 'schema', None)
-        self.assertRaises(TypeError, setattr, store, 'schema', 1234)
-        self.assertRaises(TypeError, setattr, store, 'schema', 'foo')
-        class Foo(): pass
-        self.assertRaises(TypeError, setattr, store, 'schema', Foo())
-
-        # cannot migrate to incompatible schema
-        invalid = _schema.Schema.from_string('''
-            prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
-            prefix xsd: <http://www.w3.org/2001/XMLSchema#>
-            prefix bsfs: <http://bsfs.ai/schema/>
-            prefix bse: <http://bsfs.ai/schema/Entity#>
-
-            bsfs:Entity rdfs:subClassOf bsfs:Node .
-            bsfs:Tag rdfs:subClassOf bsfs:Entity . # inconsistent with previous tag definition
-
-            bse:tag rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range bsfs:Tag ;
-                bsfs:unique "false"^^xsd:boolean .
-
-            ''')
-        self.assertRaises(errors.ConsistencyError, setattr, store, 'schema', invalid)
-        invalid = _schema.Schema.from_string('''
-            prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
-            prefix xsd: <http://www.w3.org/2001/XMLSchema#>
-            prefix bsfs: <http://bsfs.ai/schema/>
-            prefix bse: <http://bsfs.ai/schema/Entity#>
-
-            bsfs:Entity rdfs:subClassOf bsfs:Node .
-            bsfs:User rdfs:subClassOf bsfs:Node .
-
-            # inconsistent predicate
-            bse:tag rdfs:subClassOf bsfs:Predicate ;
-                rdfs:domain bsfs:Entity ;
-                rdfs:range bsfs:User;
-                bsfs:unique "false"^^xsd:boolean .
-
-            ''')
-        self.assertRaises(errors.ConsistencyError, setattr, store, 'schema', invalid)
-
-
-    def test_transaction(self):
-        # store setup
-        store = SparqlStore.Open()
-        store.schema = self.schema
-        p_tag = store.schema.predicate(ns.bse.tag)
-        p_filesize = store.schema.predicate(ns.bse.filesize)
-        # prepare node types
-        ent_type = store.schema.node(ns.bsfs.Entity)
-        tag_type = store.schema.node(ns.bsfs.Tag)
-        ent_ids = {URI('http://example.com/me/entity#1234'), URI('http://example.com/me/entity#4321')}
-        tag_ids = {URI('http://example.com/me/tag#1234'), URI('http://example.com/me/tag#4321')}
-        # target instances
-        instances = {
-            # node instances
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/tag#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            (rdflib.URIRef('http://example.com/me/tag#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            # links
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            }
-
-        # add some data
-        store.create(ent_type, ent_ids)
-        store.create(tag_type, tag_ids)
-        store.set(ent_type, ent_ids, p_tag, tag_ids)
-        store.set(ent_type, ent_ids, p_filesize, {1234})
-        # current transaction is visible
-        self.assertSetEqual(set(store._graph), instances | {
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(1234, datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(1234, datatype=rdflib.XSD.integer)),
-            })
-
-        # rollback undoes previous changes
-        store.rollback()
-        self.assertSetEqual(set(store._graph), set())
-
-        # add some data once more
-        store.create(ent_type, ent_ids)
-        store.create(tag_type, tag_ids)
-        store.set(ent_type, ent_ids, p_tag, tag_ids)
-        store.set(ent_type, ent_ids, p_filesize, {1234})
-        # current transaction is visible
-        self.assertSetEqual(set(store._graph), instances | {
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(1234, datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(1234, datatype=rdflib.XSD.integer)),
-            })
-
-        # commit saves changes
-        store.commit()
-        self.assertSetEqual(set(store._graph), instances | {
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(1234, datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(1234, datatype=rdflib.XSD.integer)),
-            })
-
-        # add additional data
-        store.create(ent_type, {URI('http://example.com/me/entity#hello')})
-        store.set(ent_type, {URI('http://example.com/me/entity#hello')}, p_tag, tag_ids)
-        store.set(ent_type, ent_ids, p_filesize, {4321})
-        self.assertSetEqual(set(store._graph), instances | {
-            (rdflib.URIRef('http://example.com/me/entity#hello'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#hello'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#hello'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(4321, datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(4321, datatype=rdflib.XSD.integer)),
-            })
-
-        # rollback undoes only changes since last commit
-        store.rollback()
-        self.assertSetEqual(set(store._graph), instances | {
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(1234, datatype=rdflib.XSD.integer)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal(1234, datatype=rdflib.XSD.integer)),
-            })
-
-
-    def test_exists(self):
-        # store setup
-        store = SparqlStore.Open()
-        store.schema = self.schema
-        # prepare node types
-        ent_type = store.schema.node(ns.bsfs.Entity)
-        tag_type = store.schema.node(ns.bsfs.Tag)
-        # create node instances
-        ent_ids = {
-            URI('http://example.com/me/entity#1234'),
-            URI('http://example.com/me/entity#4321'),
-            }
-        tag_ids = {
-            URI('http://example.com/me/tag#1234'),
-            URI('http://example.com/me/tag#4321'),
-            }
-        store.create(ent_type, ent_ids)
-        store.create(tag_type, tag_ids)
-
-        # exists returns all existing nodes of the correct type
-        self.assertSetEqual(ent_ids, set(store.exists(ent_type, ent_ids)))
-        self.assertSetEqual(tag_ids, set(store.exists(tag_type, tag_ids)))
-        # exists returns only nodes that match the type
-        self.assertSetEqual(set(), set(store.exists(ent_type, tag_ids)))
-        self.assertSetEqual({URI('http://example.com/me/entity#1234')}, set(store.exists(ent_type, {
-            URI('http://example.com/me/tag#1234'),
-            URI('http://example.com/me/entity#1234'),
-            })))
-        # exists returns only nodes that exist
-        self.assertSetEqual(set(), set(store.exists(ent_type, {
-            URI('http://example.com/me/entity#foo'),
-            URI('http://example.com/me/entity#bar'),
-            })))
-        self.assertSetEqual({URI('http://example.com/me/entity#1234')}, set(store.exists(ent_type, {
-            URI('http://example.com/me/entity#foo'),
-            URI('http://example.com/me/entity#1234'),
-            })))
-
-
-    def test_create(self):
-        # setup
-        store = SparqlStore.Open()
-        store.schema = self.schema
-
-        # node type must be valid
-        self.assertRaises(errors.ConsistencyError, store.create, self.schema.node(ns.bsfs.Entity).get_child(ns.bsfs.invalid), {
-            URI('http://example.com/me/entity#1234'), URI('http://example.com/me/entity#4321')})
-
-        # can create some nodes
-        ent_type = store.schema.node(ns.bsfs.Entity)
-        store.create(ent_type, {URI('http://example.com/me/entity#1234'), URI('http://example.com/me/entity#4321')})
-        self.assertSetEqual(set(store._graph), {
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            })
-
-        # existing nodes are skipped
-        store.create(ent_type, {URI('http://example.com/me/entity#1234'), URI('http://example.com/me/entity#5678')})
-        self.assertSetEqual(set(store._graph), {
-            # previous triples
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            # new triples
-            (rdflib.URIRef('http://example.com/me/entity#5678'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            })
-
-        # can create nodes of a different type
-        tag_type = store.schema.node(ns.bsfs.Tag)
-        store.create(tag_type, {URI('http://example.com/me/tag#1234'), URI('http://example.com/me/tag#4321')})
-        self.assertSetEqual(set(store._graph), {
-            # previous triples
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#5678'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            # new triples
-            (rdflib.URIRef('http://example.com/me/tag#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            (rdflib.URIRef('http://example.com/me/tag#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            })
-
-        # creation does not change types of existing nodes
-        tag_type = store.schema.node(ns.bsfs.Tag)
-        store.create(tag_type, {URI('http://example.com/me/entity#1234'), URI('http://example.com/me/entity#4321')})
-        self.assertSetEqual(set(store._graph), {
-            # previous triples
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            (rdflib.URIRef('http://example.com/me/entity#5678'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Entity)),
-            # new triples
-            (rdflib.URIRef('http://example.com/me/tag#1234'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            (rdflib.URIRef('http://example.com/me/tag#4321'), rdflib.RDF.type, rdflib.URIRef(ns.bsfs.Tag)),
-            })
-
-
-    def test_set(self):
-        # store setup
-        store = SparqlStore.Open()
-        store.schema = self.schema
-        # prepare node types
-        ent_type = store.schema.node(ns.bsfs.Entity)
-        user_type = store.schema.node(ns.bsfs.User)
-        tag_type = store.schema.node(ns.bsfs.Tag)
-        # prepare predicates
-        p_filesize = store.schema.predicate(ns.bse.filesize)
-        p_comment = store.schema.predicate(ns.bse.comment)
-        p_author = store.schema.predicate(ns.bse.author)
-        p_tag = store.schema.predicate(ns.bse.tag)
-        p_invalid = store.schema.predicate(ns.bsfs.Predicate).get_child(ns.bsfs.foo, range=store.schema.node(ns.bsfs.Tag))
-        # create node instances
-        ent_ids = {
-            URI('http://example.com/me/entity#1234'),
-            URI('http://example.com/me/entity#4321'),
-            }
-        tag_ids = {
-            URI('http://example.com/me/tag#1234'),
-            URI('http://example.com/me/tag#4321'),
-            URI('http://example.com/me/tag#foo'),
-            URI('http://example.com/me/tag#bar'),
-            URI('http://example.com/me/tag#foobar'),
-            URI('http://example.com/me/tag#xyz'),
-            }
-        user_ids = {
-            URI('http://example.com/me/user#1234'),
-            URI('http://example.com/me/user#4321'),
-            }
-        store.create(ent_type, ent_ids)
-        store.create(tag_type, tag_ids)
-        store.create(user_type, user_ids)
-
-        # invalid node_type is not permitted
-        self.assertRaises(errors.ConsistencyError, store.set, self.schema.node(ns.bsfs.Node).get_child(ns.bse.foo),
-            ent_ids, p_comment, {'hello world'})
-
-        # invalid predicate is not permitted
-        self.assertRaises(errors.ConsistencyError, store.set, ent_type, ent_ids, p_invalid, {'http://example.com/me/tag#1234'})
-
-        # predicate must match node_type
-        self.assertRaises(errors.ConsistencyError, store.set, tag_type, tag_ids, p_filesize, {1234})
-
-        # empty value does not change the graph
-        plen = len(store._graph)
-        store.set(ent_type, ent_ids, p_filesize, [])
-        store.set(ent_type, ent_ids, p_comment, [])
-        store.set(ent_type, ent_ids, p_author, [])
-        store.set(ent_type, ent_ids, p_tag, [])
-        self.assertEqual(plen, len(store._graph))
-
-        # cannot set multiple values on unique predicates
-        self.assertRaises(ValueError, store.set, ent_type, ent_ids, p_filesize, {1234, 4321})
-        self.assertRaises(ValueError, store.set, ent_type, ent_ids, p_author, {URI('http://example.com/me/user#1234'), URI('http://example.com/me/user#4321')})
-
-        # value nodes must exist
-        self.assertRaises(errors.InstanceError, store.set, ent_type, ent_ids, p_author, {URI('http://example.com/me/user#invalid')})
-        self.assertRaises(errors.InstanceError, store.set, ent_type, ent_ids, p_tag, {URI('http://example.com/me/tag#invalid')})
-
-        # value node types must be consistent with the predicate
-        self.assertRaises(errors.InstanceError, store.set, ent_type, ent_ids, p_author, {URI('http://example.com/me/entity#1234')})
-        self.assertRaises(errors.InstanceError, store.set, ent_type, ent_ids, p_tag, {URI('http://example.com/me/entity#1234')})
-
-        # all value nodes must exist and be consistent
-        self.assertRaises(errors.InstanceError, store.set, ent_type, ent_ids, p_tag, {
-            URI('http://example.com/me/tag#1234'), URI('http://example.com/me/tag#invalid'), URI('http://example.com/me/entity#1234')})
-
-
-        # set unique literal
-        store.set(ent_type, ent_ids, p_filesize, {1234})
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            set(store._graph))
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            set(store._graph))
-        # re-assigning the same node changes nothing
-        store.set(ent_type, ent_ids, p_filesize, {1234})
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            set(store._graph))
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            set(store._graph))
-        # cannot set multiple unique literals
-        self.assertRaises(ValueError, store.set, ent_type, ent_ids, p_filesize, {1234, 4321}) # same test as above
-        # unique literals are overwritten by set
-        store.set(ent_type, ent_ids, p_filesize, {4321})
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('4321', datatype=rdflib.XSD.integer)),
-            set(store._graph))
-        self.assertNotIn(
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            set(store._graph))
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('4321', datatype=rdflib.XSD.integer)),
-            set(store._graph))
-        self.assertNotIn(
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_filesize.uri), rdflib.Literal('1234', datatype=rdflib.XSD.integer)),
-            set(store._graph))
-
-        # set non-unique literal
-        store.set(ent_type, ent_ids, p_comment, {'foobar'})
-        self.assertTrue(set(store._graph).issuperset({
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foobar', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foobar', datatype=rdflib.XSD.string)),
-            }))
-        # re-assigning the same node changes nothing
-        store.set(ent_type, ent_ids, p_comment, {'foobar'})
-        self.assertTrue(set(store._graph).issuperset({
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foobar', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foobar', datatype=rdflib.XSD.string)),
-            }))
-        # can set multiple non-unique literals at once
-        store.set(ent_type, ent_ids, p_comment, {'foo', 'bar'})
-        self.assertTrue(set(store._graph).issuperset({
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foo', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_comment.uri), rdflib.Literal('bar', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foo', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_comment.uri), rdflib.Literal('bar', datatype=rdflib.XSD.string)),
-            }))
-        # non-unique literals are appended by set
-        store.set(ent_type, ent_ids, p_comment, {'hello world'})
-        self.assertTrue(set(store._graph).issuperset({
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foo', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_comment.uri), rdflib.Literal('bar', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_comment.uri), rdflib.Literal('hello world', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_comment.uri), rdflib.Literal('foo', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_comment.uri), rdflib.Literal('bar', datatype=rdflib.XSD.string)),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_comment.uri), rdflib.Literal('hello world', datatype=rdflib.XSD.string)),
-            }))
-
-        # set unique node
-        store.set(ent_type, ent_ids, p_author, {URI('http://example.com/me/user#1234')})
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me/user#1234')),
-            set(store._graph))
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me/user#1234')),
-            set(store._graph))
-        # re-assigning the same node changes nothing
-        store.set(ent_type, ent_ids, p_author, {URI('http://example.com/me/user#1234')})
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me/user#1234')),
-            set(store._graph))
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me/user#1234')),
-            set(store._graph))
-        # cannot set multiple unique nodes
-        self.assertRaises(ValueError, store.set, ent_type, ent_ids, p_author, {URI('http://example.com/me/user#1234'), URI('http://example.com/me/user#4321')})
-        # unique nodes are overwritten by set
-        store.set(ent_type, ent_ids, p_author, {URI('http://example.com/me/user#4321')})
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me/user#4321')),
-            set(store._graph))
-        self.assertNotIn(
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me/user#1234')),
-            set(store._graph))
-        self.assertIn(
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me/user#4321')),
-            set(store._graph))
-        self.assertNotIn(
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_author.uri), rdflib.URIRef('http://example.com/me/user#1234')),
-            set(store._graph))
-
-        # set non-unique node
-        store.set(ent_type, ent_ids, p_tag, {'http://example.com/me/tag#foobar'})
-        self.assertTrue(set(store._graph).issuperset({
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#foobar')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#foobar')),
-            }))
-        # re-assigning the same node changes nothing
-        store.set(ent_type, ent_ids, p_tag, {'http://example.com/me/tag#foobar'})
-        self.assertTrue(set(store._graph).issuperset({
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#foobar')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#foobar')),
-            }))
-        # can set multiple non-unique literals at once
-        store.set(ent_type, ent_ids, p_tag, {'http://example.com/me/tag#1234', 'http://example.com/me/tag#4321'})
-        self.assertTrue(set(store._graph).issuperset({
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            }))
-        # non-unique nodes are appended by set
-        store.set(ent_type, ent_ids, p_tag, {'http://example.com/me/tag#foo', 'http://example.com/me/tag#bar'})
-        self.assertTrue(set(store._graph).issuperset({
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#foo')),
-            (rdflib.URIRef('http://example.com/me/entity#1234'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#bar')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#1234')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#4321')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#foo')),
-            (rdflib.URIRef('http://example.com/me/entity#4321'), rdflib.URIRef(p_tag.uri), rdflib.URIRef('http://example.com/me/tag#bar')),
-            }))
-
-        # nothing happens when no guids are given
-        plen = len(store._graph)
-        store.set(ent_type, set(), p_comment, {'xyz'})
-        store.set(ent_type, set(), p_tag, {URI('http://example.com/me/tag#xyz')})
-        self.assertEqual(plen, len(store._graph))
-
-        # guids must be instances of node_type
-        self.assertRaises(errors.InstanceError, store.set, ent_type, tag_ids, p_comment, {'xyz'})
-        # inexistent guids
-        self.assertRaises(errors.InstanceError, store.set, ent_type, {URI('http://example.com/me/entity#foobar')}, p_comment, {'xyz'})
-
-
-## main ##
-
-if __name__ == '__main__':
-    unittest.main()
-
-## EOF ##