Fetch in graph including results view

7 files changed, 734 insertions, 16 deletions

diff --git a/.pylintrc b/.pylintrc
index bcb2a86..6b7f471 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -76,10 +76,10 @@ max-attributes=7
 max-bool-expr=5
 
 # Maximum number of branch for function / method body.
-max-branches=15
+max-branches=20
 
 # Maximum number of locals for function / method body.
-max-locals=15
+max-locals=20
 
 # Maximum number of parents for a class (see R0901).
 max-parents=7
@@ -91,7 +91,7 @@ max-public-methods=20
 max-returns=15
 
 # Maximum number of statements in function / method body.
-max-statements=50
+max-statements=100
 
 # Minimum number of public methods for a class (see R0903).
 min-public-methods=1
diff --git a/bsfs/graph/ac/base.py b/bsfs/graph/ac/base.py
index 0703e2e..79b09e5 100644
--- a/bsfs/graph/ac/base.py
+++ b/bsfs/graph/ac/base.py
@@ -72,4 +72,8 @@ class AccessControlBase(abc.ABC):
     def filter_read(self, node_type: schema.Node, query: ast.filter.FilterExpression) -> ast.filter.FilterExpression:
         """Re-write a filter *query* to get (i.e., read) *node_type* nodes."""
 
+    @abc.abstractmethod
+    def fetch_read(self, node_type: schema.Node, query: ast.fetch.FetchExpression) -> ast.fetch.FetchExpression:
+        """Re-write a fetch *query* to get (i.e, read) values for *node_type* nodes."""
+
 ## EOF ##
diff --git a/bsfs/graph/ac/null.py b/bsfs/graph/ac/null.py
index 12b4e87..6a923a5 100644
--- a/bsfs/graph/ac/null.py
+++ b/bsfs/graph/ac/null.py
@@ -54,4 +54,8 @@ class NullAC(base.AccessControlBase):
         """Re-write a filter *query* to get (i.e., read) *node_type* nodes."""
         return query
 
+    def fetch_read(self, node_type: schema.Node, query: ast.fetch.FetchExpression) -> ast.fetch.FetchExpression:
+        """Re-write a fetch *query* to get (i.e, read) values for *node_type* nodes."""
+        return query
+
 ## EOF ##
diff --git a/bsfs/graph/nodes.py b/bsfs/graph/nodes.py
index 5a93f77..a4ba45f 100644
--- a/bsfs/graph/nodes.py
+++ b/bsfs/graph/nodes.py
@@ -5,17 +5,20 @@ A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
 # imports
+from collections import abc
 import time
 import typing
 
 # bsfs imports
-from bsfs import schema as _schema
+from bsfs import schema as bsc
 from bsfs.namespace import ns
+from bsfs.query import ast, validate
 from bsfs.triple_store import TripleStoreBase
 from bsfs.utils import errors, URI, typename
 
 # inner-module imports
 from . import ac
+from . import result
 
 # exports
 __all__: typing.Sequence[str] = (
@@ -37,7 +40,7 @@ class Nodes():
     _user: URI
 
     # node type.
-    _node_type: _schema.Node
+    _node_type: bsc.Node
 
     # guids of nodes. Can be empty.
     _guids: typing.Set[URI]
@@ -46,13 +49,16 @@ class Nodes():
             self,
             backend: TripleStoreBase,
             user: URI,
-            node_type: _schema.Node,
+            node_type: bsc.Node,
             guids: typing.Iterable[URI],
             ):
+        # set main members
         self._backend = backend
         self._user = user
         self._node_type = node_type
         self._guids = set(guids)
+        # create helper instances
+        # FIXME: Assumes that the schema does not change while the instance is in use!
         self._ac = ac.NullAC(self._backend, self._user)
 
     def __eq__(self, other: typing.Any) -> bool:
@@ -72,7 +78,7 @@ class Nodes():
         return f'{typename(self)}({self._node_type}, {self._guids})'
 
     @property
-    def node_type(self) -> _schema.Node:
+    def node_type(self) -> bsc.Node:
         """Return the node's type."""
         return self._node_type
 
@@ -83,7 +89,7 @@ class Nodes():
 
     def set(
             self,
-            pred: URI, # FIXME: URI or _schema.Predicate?
+            pred: URI, # FIXME: URI or bsc.Predicate?
             value: typing.Any,
             ) -> 'Nodes':
         """Set predicate *pred* to *value*."""
@@ -91,7 +97,7 @@ class Nodes():
 
     def set_from_iterable(
             self,
-            predicate_values: typing.Iterable[typing.Tuple[URI, typing.Any]], # FIXME: URI or _schema.Predicate?
+            predicate_values: typing.Iterable[typing.Tuple[URI, typing.Any]], # FIXME: URI or bsc.Predicate?
             ) -> 'Nodes':
         """Set mutliple predicate-value pairs at once."""
         # TODO: Could group predicate_values by predicate to gain some efficiency
@@ -120,6 +126,119 @@ class Nodes():
 
         return self
 
+    def get(
+            self,
+            *paths: typing.Union[URI, typing.Iterable[URI]],
+            view: typing.Union[typing.Type[list], typing.Type[dict]] = dict,
+            **view_kwargs,
+            ) -> typing.Any:
+        """Get values or nodes at *paths*.
+        Return an iterator (view=list) or a dict (view=dict) over the results.
+        """
+        # check args
+        if len(paths) == 0:
+            raise AttributeError('expected at least one path, found none')
+        if view not in (dict, list):
+            raise ValueError(f'expected dict or list, found {view}')
+        # process paths: create fetch ast, build name mapping, and find unique paths
+        schema = self._backend.schema
+        statements = set()
+        name2path = {}
+        unique_paths = set() # paths that result in a single (unique) value
+        normpath: typing.Tuple[URI, ...]
+        for idx, path in enumerate(paths):
+            # normalize path
+            if isinstance(path, str):
+                normpath = (URI(path), )
+            elif isinstance(path, abc.Iterable):
+                if not all(isinstance(step, str) for step in path):
+                    raise TypeError(path)
+                normpath = tuple(URI(step) for step in path)
+            else:
+                raise TypeError(path)
+            # check path's schema consistency
+            if not all(schema.has_predicate(pred) for pred in normpath):
+                raise errors.ConsistencyError(f'path is not fully covered by the schema: {path}')
+            # check path's uniqueness
+            if all(schema.predicate(pred).unique for pred in normpath):
+                unique_paths.add(path)
+            # fetch tail predicate
+            tail = schema.predicate(normpath[-1])
+            # determine tail ast node type
+            factory = ast.fetch.Node if isinstance(tail.range, bsc.Node) else ast.fetch.Value
+            # assign name
+            name = f'fetch{idx}'
+            name2path[name] = (path, tail)
+            # create tail ast node
+            curr: ast.fetch.FetchExpression = factory(tail.uri, name)
+            # walk towards front
+            hop: URI
+            for hop in normpath[-2::-1]:
+                curr = ast.fetch.Fetch(hop, curr)
+            # add to fetch query
+            statements.add(curr)
+        # aggregate fetch statements
+        if len(statements) == 1:
+            fetch = next(iter(statements))
+        else:
+            fetch = ast.fetch.All(*statements)
+        # add access controls to fetch
+        fetch = self._ac.fetch_read(self.node_type, fetch)
+
+        # compose filter ast
+        filter = ast.filter.IsIn(self.guids) # pylint: disable=redefined-builtin
+        # add access controls to filter
+        filter = self._ac.filter_read(self.node_type, filter)
+
+        # validate queries
+        validate.Filter(self._backend.schema)(self.node_type, filter)
+        validate.Fetch(self._backend.schema)(self.node_type, fetch)
+
+        # process results, convert if need be
+        def triple_iter():
+            # query the backend
+            triples = self._backend.fetch(self.node_type, filter, fetch)
+            # process triples
+            for root, name, raw in triples:
+                # get node
+                node = Nodes(self._backend, self._user, self.node_type, {root})
+                # get path
+                path, tail = name2path[name]
+                # covert raw to value
+                if isinstance(tail.range, bsc.Node):
+                    value = Nodes(self._backend, self._user, tail.range, {raw})
+                else:
+                    value = raw
+                # emit triple
+                yield node, path, value
+
+        # simplify by default
+        view_kwargs['node'] = view_kwargs.get('node', len(self._guids) == 1)
+        view_kwargs['path'] = view_kwargs.get('path', len(paths) == 1)
+        view_kwargs['value'] = view_kwargs.get('value', True)
+
+        # return results view
+        if view == list:
+            return result.to_list_view(
+                triple_iter(),
+                # aggregation args
+                **view_kwargs,
+                )
+
+        if view == dict:
+            return result.to_dict_view(
+                triple_iter(),
+                # context
+                len(self._guids) == 1,
+                len(paths) == 1,
+                unique_paths,
+                # aggregation args
+                **view_kwargs,
+                )
+
+        raise errors.UnreachableError() # view was already checked
+
+
     def __set(self, predicate: URI, value: typing.Any):
         """
         """
@@ -145,7 +264,7 @@ class Nodes():
         guids = set(self._ensure_nodes(node_type, guids))
 
         # check value
-        if isinstance(pred.range, _schema.Literal):
+        if isinstance(pred.range, bsc.Literal):
             # check write permissions on existing nodes
             # As long as the user has write permissions, we don't restrict
             # the creation or modification of literal values.
@@ -160,7 +279,7 @@ class Nodes():
                 [value],
                 )
 
-        elif isinstance(pred.range, _schema.Node):
+        elif isinstance(pred.range, bsc.Node):
             # check value type
             if not isinstance(value, Nodes):
                 raise TypeError(value)
@@ -192,7 +311,7 @@ class Nodes():
         else:
             raise errors.UnreachableError()
 
-    def _ensure_nodes(self, node_type: _schema.Node, guids: typing.Iterable[URI]):
+    def _ensure_nodes(self, node_type: bsc.Node, guids: typing.Iterable[URI]):
         """
         """
         # check node existence
diff --git a/bsfs/graph/result.py b/bsfs/graph/result.py
new file mode 100644
index 0000000..3009801
--- /dev/null
+++ b/bsfs/graph/result.py
@@ -0,0 +1,112 @@
+"""
+
+Part of the BlackStar filesystem (bsfs) module.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# imports
+from collections import defaultdict
+import typing
+
+# bsfs imports
+from bsfs.utils import URI
+
+# exports
+__all__: typing.Sequence[str] = (
+    'to_list_view',
+    'to_dict_view',
+    )
+
+
+## code ##
+
+def to_list_view(
+        triples,
+        # aggregators
+        node: bool,
+        path: bool,
+        value: bool, # pylint: disable=unused-argument
+        ):
+    """Return an iterator over results.
+
+    Dependent on the *node*, *path*, and *value* flags,
+    the respective component is omitted.
+
+    """
+    if node and path:
+        return iter(val for _, _, val in triples)
+    if node:
+        return iter((pred, val) for _, pred, val in triples)
+    if path:
+        return iter((subj, val) for subj, _, val in triples)
+    return iter((subj, pred, val) for subj, pred, val in triples)
+
+
+def to_dict_view(
+        triples,
+        # context
+        one_node: bool,
+        one_path: bool,
+        unique_paths: typing.Set[typing.Union[URI, typing.Iterable[URI]]],
+        # aggregators
+        node: bool,
+        path: bool,
+        value: bool,
+        ) -> typing.Any:
+    """Return a dict of results.
+
+    Note that triples are materialized to create this view.
+
+    The returned structure depends on the *node*, *path*, and *value* flags.
+    If all flags are set to False, returns a dict(node -> dict(path -> set(values))).
+    Setting a flag to true omits or simplifies the respective component (if possible).
+
+    """
+    # NOTE: To create a dict, we need to materialize or make further assumptions
+    # (e.g., sorted in a specific order).
+
+    data: typing.Any # disable type checks on data since it's very flexibly typed.
+
+    # FIXME: type of data can be overwritten later on (if value)
+
+    if node and path:
+        data = set()
+    elif node ^ path:
+        data = defaultdict(set)
+    else:
+        data = defaultdict(lambda: defaultdict(set))
+
+    for subj, pred, val in triples:
+        unique = pred in unique_paths
+        if node and path:
+            if value and unique and one_node and one_path:
+                return val
+            data.add(val)
+        elif node:
+            # remove node from result, group by predicate
+            if value and unique and one_node:
+                data[pred] = val
+            else:
+                data[pred].add(val)
+        elif path:
+            # remove predicate from result, group by node
+            if value and unique and one_path:
+                data[subj] = val
+            else:
+                data[subj].add(val)
+        else:
+            if value and unique:
+                data[subj][pred] = val
+            else:
+                data[subj][pred].add(val)
+
+    # FIXME: Combine multiple Nodes instances into one?
+
+    # convert defaultdict to ordinary dict
+    if node and path:
+        return data
+    if node ^ path:
+        return dict(data)
+    return {key: dict(val) for key, val in data.items()}
+
+## EOF ##
diff --git a/test/graph/test_nodes.py b/test/graph/test_nodes.py
index 2870f35..a4e07ee 100644
--- a/test/graph/test_nodes.py
+++ b/test/graph/test_nodes.py
@@ -9,8 +9,8 @@ import rdflib
 import unittest
 
 # bsie imports
-from bsfs import schema as _schema
-from bsfs.namespace import ns
+from bsfs import schema as bsc
+from bsfs.namespace import Namespace, ns
 from bsfs.triple_store.sparql import SparqlStore
 from bsfs.utils import errors, URI
 
@@ -20,11 +20,13 @@ from bsfs.graph.nodes import Nodes
 
 ## code ##
 
+bst = Namespace('http://bsfs.ai/schema/Tag')
+
 class TestNodes(unittest.TestCase):
     def setUp(self):
         # initialize backend
         self.backend = SparqlStore()
-        self.backend.schema = _schema.from_string('''
+        self.backend.schema = bsc.from_string('''
             prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>
             prefix xsd: <http://www.w3.org/2001/XMLSchema#>
 
@@ -67,6 +69,11 @@ class TestNodes(unittest.TestCase):
                 rdfs:range bsfs:User ;
                 bsfs:unique "true"^^xsd:boolean .
 
+            bst:label rdfs:subClassOf bsfs:Predicate ;
+                rdfs:domain bsfs:Tag ;
+                rdfs:range xsd:string ;
+                bsfs:unique "true"^^xsd:boolean .
+
             bst:representative rdfs:subClassOf bsfs:Predicate ;
                 rdfs:domain bsfs:Tag ;
                 rdfs:range bsfs:Entity ;
@@ -89,7 +96,8 @@ class TestNodes(unittest.TestCase):
             (rdflib.URIRef(ns.bse.filesize), rdflib.RDFS.subClassOf, rdflib.URIRef(ns.bsfs.Predicate)),
             (rdflib.URIRef(ns.bse.tag), rdflib.RDFS.subClassOf, rdflib.URIRef(ns.bsfs.Predicate)),
             (rdflib.URIRef(ns.bse.author), rdflib.RDFS.subClassOf, rdflib.URIRef(ns.bsfs.Predicate)),
-            (rdflib.URIRef('http://bsfs.ai/schema/Tag#representative'), rdflib.RDFS.subClassOf, rdflib.URIRef(ns.bsfs.Predicate)),
+            (rdflib.URIRef(bst.representative), rdflib.RDFS.subClassOf, rdflib.URIRef(ns.bsfs.Predicate)),
+            (rdflib.URIRef(bst.label), rdflib.RDFS.subClassOf, rdflib.URIRef(ns.bsfs.Predicate)),
             }
         # Nodes constructor args
         self.user = URI('http://example.com/me')
@@ -371,6 +379,85 @@ class TestNodes(unittest.TestCase):
             (self.p_author.uri, Nodes(self.backend, self.user, self.user_type, {URI('http://example.com/me/user#1234'), URI('http://example.com/me/user#4321')}))))
         self.assertSetEqual(curr, set(self.backend._graph))
 
+    def test_fetch(self):
+        # setup: add some instances
+        Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}) \
+            .set(ns.bse.comment, 'hello world') \
+            .set(ns.bse.filesize, 1234) \
+            .set(ns.bse.tag, Nodes(self.backend, self.user, self.tag_type, {'http://example.com/me/tag#1234'}))
+        Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#4321'}) \
+            .set(ns.bse.filesize, 4321) \
+            .set(ns.bse.tag, Nodes(self.backend, self.user, self.tag_type, {'http://example.com/me/tag#4321'}))
+        Nodes(self.backend, self.user, self.tag_type, {'http://example.com/me/tag#1234'}) \
+            .set(bst.label, 'tag_label_1234')
+        Nodes(self.backend, self.user, self.tag_type, {'http://example.com/me/tag#4321'}) \
+            .set(bst.label, 'tag_label_4321')
+        # setup: get nodes instance
+        nodes = Nodes(self.backend, self.user, self.ent_type, self.ent_ids)
+        # must pass at least one path
+        self.assertRaises(AttributeError, nodes.get)
+        # view must be list or dict
+        self.assertRaises(ValueError, nodes.get, ns.bse.filesize, view='hello')
+        self.assertRaises(ValueError, nodes.get, ns.bse.filesize, view=1234)
+        self.assertRaises(ValueError, nodes.get, ns.bse.filesize, view=tuple)
+        # can pass path as URI
+        self.assertDictEqual(nodes.get(ns.bse.filesize), {
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}): 1234,
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#4321'}): 4321,
+            })
+        # can pass path as sequence of URI
+        self.assertDictEqual(nodes.get((ns.bse.tag, bst.label)), {
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}): {'tag_label_1234'},
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#4321'}): {'tag_label_4321'},
+            })
+        # get returns the same path that was passed
+        self.assertCountEqual(list(nodes.get((ns.bse.tag, bst.label), path=False, view=list)), [
+            (Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}), (ns.bse.tag, bst.label), 'tag_label_1234'),
+            (Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#4321'}), (ns.bse.tag, bst.label), 'tag_label_4321'),
+            ])
+        self.assertCountEqual(list(nodes.get([ns.bse.tag, bst.label], path=False, view=list)), [
+            (Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}), [ns.bse.tag, bst.label], 'tag_label_1234'),
+            (Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#4321'}), [ns.bse.tag, bst.label], 'tag_label_4321'),
+            ])
+        # paths must be URI or sequence thereof
+        self.assertRaises(TypeError, nodes.get, 1234)
+        self.assertRaises(TypeError, nodes.get, (ns.bse.tag, 1234))
+        self.assertRaises(TypeError, nodes.get, (1234, ns.bse.tag))
+        self.assertRaises(errors.ConsistencyError, nodes.get, 'hello world')
+        self.assertRaises(errors.ConsistencyError, nodes.get, ns.bse.invalid)
+        self.assertRaises(errors.ConsistencyError, nodes.get, (ns.bse.tag, bst.invalid))
+        # can pass multiple paths
+        self.assertDictEqual(nodes.get(ns.bse.filesize, (ns.bse.tag, bst.label)), {
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}): {
+                ns.bse.filesize: 1234,
+                (ns.bse.tag, bst.label): {'tag_label_1234'},
+                },
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#4321'}): {
+                ns.bse.filesize: 4321,
+                (ns.bse.tag, bst.label): {'tag_label_4321'},
+                },
+            })
+        # get respects view
+        self.assertDictEqual(nodes.get(ns.bse.filesize, view=dict), {
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}): 1234,
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#4321'}): 4321,
+            })
+        self.assertSetEqual(set(nodes.get(ns.bse.filesize, view=list)), {
+            (Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}), 1234),
+            (Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#4321'}), 4321),
+            })
+        # get returns Nodes instance when fetching a node
+        self.assertDictEqual(nodes.get(ns.bse.tag), {
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}):
+                {Nodes(self.backend, self.user, self.tag_type, {'http://example.com/me/tag#1234'})},
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#4321'}):
+                {Nodes(self.backend, self.user, self.tag_type, {'http://example.com/me/tag#4321'})},
+            })
+        # get returns a value when fetching a value and omits missing values
+        self.assertDictEqual(nodes.get(ns.bse.comment), {
+            Nodes(self.backend, self.user, self.ent_type, {'http://example.com/me/entity#1234'}): {'hello world'},
+            })
+
 
 ## main ##
 
diff --git a/test/graph/test_result.py b/test/graph/test_result.py
new file mode 100644
index 0000000..89b0da1
--- /dev/null
+++ b/test/graph/test_result.py
@@ -0,0 +1,392 @@
+"""
+
+Part of the bsfs test suite.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# imports
+import unittest
+
+# bsie imports
+from bsfs import schema as bsc
+from bsfs.namespace import ns
+from bsfs.utils import URI
+
+# objects to test
+from bsfs.graph.result import to_list_view, to_dict_view
+
+
+## code ##
+
+class TestListView(unittest.TestCase):
+    def setUp(self):
+        self.triples_111 = [('ent#1234', ns.bse.iso, 123)]
+        self.triples_11U = [('ent#1234', ns.bse.tag, 'tag#1234'),
+                            ('ent#1234', ns.bse.tag, 'tag#5678')]
+        self.triples_1M1 = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#1234', ns.bse.t_created, '2010-01-02')]
+        self.triples_1MU = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#1234', ns.bse.tag, 'tag#1234'),
+                            ('ent#1234', ns.bse.tag, 'tag#5678')]
+        self.triples_N11 = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#4321', ns.bse.iso, 321)]
+        self.triples_N1U = [('ent#1234', ns.bse.tag, 'tag#1234'),
+                            ('ent#1234', ns.bse.tag, 'tag#5678'),
+                            ('ent#4321', ns.bse.tag, 'tag#4321')]
+        self.triples_NM1 = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#1234', ns.bse.t_created, '2010-01-02'),
+                            ('ent#4321', ns.bse.iso, 321),
+                            ('ent#4321', ns.bse.t_created, '2022-02-22')]
+        self.triples_NMU = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#1234', ns.bse.tag, 'tag#1234'),
+                            ('ent#1234', ns.bse.tag, 'tag#5678'),
+                            ('ent#4321', ns.bse.iso, 321),
+                            ('ent#4321', ns.bse.t_created, '2022-02-22')]
+
+    def test_copy(self):
+        # iterator yields tuples
+        self.assertIsInstance(list(to_list_view([('subject', 'predicate', 'object')], node=False, path=False, value=False))[0], tuple)
+        # components are not changed
+        class Foo(): pass
+        foo = Foo()
+        self.assertListEqual(list(to_list_view([('subject', 'predicate', 'object')], node=False, path=False, value=False)),
+            [('subject', 'predicate', 'object')])
+        self.assertListEqual(list(to_list_view([(foo, 'predicate', 'object')], node=False, path=False, value=False)),
+            [(foo, 'predicate', 'object')])
+        self.assertListEqual(list(to_list_view([('subject', foo, 'object')], node=False, path=False, value=False)),
+            [('subject', foo, 'object')])
+        self.assertListEqual(list(to_list_view([('subject', 'predicate', foo)], node=False, path=False, value=False)),
+            [('subject', 'predicate', foo)])
+
+    def test_agg_none(self):
+        self.assertListEqual(list(to_list_view(self.triples_111, node=False, path=False, value=False)), self.triples_111)
+        self.assertListEqual(list(to_list_view(self.triples_11U, node=False, path=False, value=False)), self.triples_11U)
+        self.assertListEqual(list(to_list_view(self.triples_1M1, node=False, path=False, value=False)), self.triples_1M1)
+        self.assertListEqual(list(to_list_view(self.triples_1MU, node=False, path=False, value=False)), self.triples_1MU)
+        self.assertListEqual(list(to_list_view(self.triples_N11, node=False, path=False, value=False)), self.triples_N11)
+        self.assertListEqual(list(to_list_view(self.triples_N1U, node=False, path=False, value=False)), self.triples_N1U)
+        self.assertListEqual(list(to_list_view(self.triples_NM1, node=False, path=False, value=False)), self.triples_NM1)
+        self.assertListEqual(list(to_list_view(self.triples_NMU, node=False, path=False, value=False)), self.triples_NMU)
+
+    def test_agg_node(self):
+        self.assertListEqual(list(to_list_view(self.triples_111, node=True, path=False, value=False)),
+            [(ns.bse.iso, 123)])
+        self.assertListEqual(list(to_list_view(self.triples_11U, node=True, path=False, value=False)),
+            [(ns.bse.tag, 'tag#1234'), (ns.bse.tag, 'tag#5678')])
+        self.assertListEqual(list(to_list_view(self.triples_1M1, node=True, path=False, value=False)),
+            [(ns.bse.iso, 123), (ns.bse.t_created, '2010-01-02')])
+        self.assertListEqual(list(to_list_view(self.triples_1MU, node=True, path=False, value=False)),
+            [(ns.bse.iso, 123), (ns.bse.tag, 'tag#1234'), (ns.bse.tag, 'tag#5678')])
+        self.assertListEqual(list(to_list_view(self.triples_N11, node=True, path=False, value=False)),
+            [(ns.bse.iso, 123), (ns.bse.iso, 321)])
+        self.assertListEqual(list(to_list_view(self.triples_N1U, node=True, path=False, value=False)),
+            [(ns.bse.tag, 'tag#1234'), (ns.bse.tag, 'tag#5678'), (ns.bse.tag, 'tag#4321')])
+        self.assertListEqual(list(to_list_view(self.triples_NM1, node=True, path=False, value=False)),
+            [(ns.bse.iso, 123), (ns.bse.t_created, '2010-01-02'), (ns.bse.iso, 321), (ns.bse.t_created, '2022-02-22')])
+        self.assertListEqual(list(to_list_view(self.triples_NMU, node=True, path=False, value=False)),
+            [(ns.bse.iso, 123), (ns.bse.tag, 'tag#1234'), (ns.bse.tag, 'tag#5678'), (ns.bse.iso, 321), (ns.bse.t_created, '2022-02-22')])
+
+    def test_agg_path(self):
+        self.assertListEqual(list(to_list_view(self.triples_111, node=False, path=True, value=False)),
+            [('ent#1234', 123)])
+        self.assertListEqual(list(to_list_view(self.triples_11U, node=False, path=True, value=False)),
+            [('ent#1234', 'tag#1234'), ('ent#1234', 'tag#5678')])
+        self.assertListEqual(list(to_list_view(self.triples_1M1, node=False, path=True, value=False)),
+            [('ent#1234', 123), ('ent#1234', '2010-01-02')])
+        self.assertListEqual(list(to_list_view(self.triples_1MU, node=False, path=True, value=False)),
+            [('ent#1234', 123), ('ent#1234', 'tag#1234'), ('ent#1234', 'tag#5678')])
+        self.assertListEqual(list(to_list_view(self.triples_N11, node=False, path=True, value=False)),
+            [('ent#1234', 123), ('ent#4321', 321)])
+        self.assertListEqual(list(to_list_view(self.triples_N1U, node=False, path=True, value=False)),
+            [('ent#1234', 'tag#1234'), ('ent#1234', 'tag#5678'), ('ent#4321', 'tag#4321')])
+        self.assertListEqual(list(to_list_view(self.triples_NM1, node=False, path=True, value=False)),
+            [('ent#1234', 123), ('ent#1234', '2010-01-02'), ('ent#4321', 321), ('ent#4321', '2022-02-22')])
+        self.assertListEqual(list(to_list_view(self.triples_NMU, node=False, path=True, value=False)),
+            [('ent#1234', 123), ('ent#1234', 'tag#1234'), ('ent#1234', 'tag#5678'), ('ent#4321', 321), ('ent#4321', '2022-02-22')])
+
+    def test_agg_node_path(self):
+        self.assertListEqual(list(to_list_view(self.triples_111, node=True, path=True, value=False)),
+            [123])
+        self.assertListEqual(list(to_list_view(self.triples_11U, node=True, path=True, value=False)),
+            ['tag#1234', 'tag#5678'])
+        self.assertListEqual(list(to_list_view(self.triples_1M1, node=True, path=True, value=False)),
+            [123, '2010-01-02'])
+        self.assertListEqual(list(to_list_view(self.triples_1MU, node=True, path=True, value=False)),
+            [123, 'tag#1234', 'tag#5678'])
+        self.assertListEqual(list(to_list_view(self.triples_N11, node=True, path=True, value=False)),
+            [123, 321])
+        self.assertListEqual(list(to_list_view(self.triples_N1U, node=True, path=True, value=False)),
+            ['tag#1234', 'tag#5678', 'tag#4321'])
+        self.assertListEqual(list(to_list_view(self.triples_NM1, node=True, path=True, value=False)),
+            [123, '2010-01-02', 321, '2022-02-22'])
+        self.assertListEqual(list(to_list_view(self.triples_NMU, node=True, path=True, value=False)),
+            [123, 'tag#1234', 'tag#5678', 321, '2022-02-22'])
+
+    def test_agg_value(self):
+        # value flag has no effect
+        self.assertListEqual(list(to_list_view(self.triples_111, node=False, path=False, value=False)), self.triples_111)
+        self.assertListEqual(list(to_list_view(self.triples_11U, node=False, path=False, value=False)), self.triples_11U)
+        self.assertListEqual(list(to_list_view(self.triples_1M1, node=False, path=False, value=False)), self.triples_1M1)
+        self.assertListEqual(list(to_list_view(self.triples_1MU, node=False, path=False, value=False)), self.triples_1MU)
+        self.assertListEqual(list(to_list_view(self.triples_N11, node=False, path=False, value=False)), self.triples_N11)
+        self.assertListEqual(list(to_list_view(self.triples_N1U, node=False, path=False, value=False)), self.triples_N1U)
+        self.assertListEqual(list(to_list_view(self.triples_NM1, node=False, path=False, value=False)), self.triples_NM1)
+        self.assertListEqual(list(to_list_view(self.triples_NMU, node=False, path=False, value=False)), self.triples_NMU)
+
+    def test_agg_node_value(self):
+        # value flag has no effect -> same test as test_agg_node
+        self.assertListEqual(list(to_list_view(self.triples_111, node=True, path=False, value=True)),
+            [(ns.bse.iso, 123)])
+        self.assertListEqual(list(to_list_view(self.triples_11U, node=True, path=False, value=True)),
+            [(ns.bse.tag, 'tag#1234'), (ns.bse.tag, 'tag#5678')])
+        self.assertListEqual(list(to_list_view(self.triples_1M1, node=True, path=False, value=True)),
+            [(ns.bse.iso, 123), (ns.bse.t_created, '2010-01-02')])
+        self.assertListEqual(list(to_list_view(self.triples_1MU, node=True, path=False, value=True)),
+            [(ns.bse.iso, 123), (ns.bse.tag, 'tag#1234'), (ns.bse.tag, 'tag#5678')])
+        self.assertListEqual(list(to_list_view(self.triples_N11, node=True, path=False, value=True)),
+            [(ns.bse.iso, 123), (ns.bse.iso, 321)])
+        self.assertListEqual(list(to_list_view(self.triples_N1U, node=True, path=False, value=True)),
+            [(ns.bse.tag, 'tag#1234'), (ns.bse.tag, 'tag#5678'), (ns.bse.tag, 'tag#4321')])
+        self.assertListEqual(list(to_list_view(self.triples_NM1, node=True, path=False, value=True)),
+            [(ns.bse.iso, 123), (ns.bse.t_created, '2010-01-02'), (ns.bse.iso, 321), (ns.bse.t_created, '2022-02-22')])
+        self.assertListEqual(list(to_list_view(self.triples_NMU, node=True, path=False, value=True)),
+            [(ns.bse.iso, 123), (ns.bse.tag, 'tag#1234'), (ns.bse.tag, 'tag#5678'), (ns.bse.iso, 321), (ns.bse.t_created, '2022-02-22')])
+
+    def test_agg_path_value(self):
+        # value flag has no effect -> same test as test_agg_path
+        self.assertListEqual(list(to_list_view(self.triples_111, node=False, path=True, value=True)),
+            [('ent#1234', 123)])
+        self.assertListEqual(list(to_list_view(self.triples_11U, node=False, path=True, value=True)),
+            [('ent#1234', 'tag#1234'), ('ent#1234', 'tag#5678')])
+        self.assertListEqual(list(to_list_view(self.triples_1M1, node=False, path=True, value=True)),
+            [('ent#1234', 123), ('ent#1234', '2010-01-02')])
+        self.assertListEqual(list(to_list_view(self.triples_1MU, node=False, path=True, value=True)),
+            [('ent#1234', 123), ('ent#1234', 'tag#1234'), ('ent#1234', 'tag#5678')])
+        self.assertListEqual(list(to_list_view(self.triples_N11, node=False, path=True, value=True)),
+            [('ent#1234', 123), ('ent#4321', 321)])
+        self.assertListEqual(list(to_list_view(self.triples_N1U, node=False, path=True, value=True)),
+            [('ent#1234', 'tag#1234'), ('ent#1234', 'tag#5678'), ('ent#4321', 'tag#4321')])
+        self.assertListEqual(list(to_list_view(self.triples_NM1, node=False, path=True, value=True)),
+            [('ent#1234', 123), ('ent#1234', '2010-01-02'), ('ent#4321', 321), ('ent#4321', '2022-02-22')])
+        self.assertListEqual(list(to_list_view(self.triples_NMU, node=False, path=True, value=True)),
+            [('ent#1234', 123), ('ent#1234', 'tag#1234'), ('ent#1234', 'tag#5678'), ('ent#4321', 321), ('ent#4321', '2022-02-22')])
+
+    def test_agg_all(self):
+        # value flag has no effect -> same test as test_agg_node_path
+        self.assertListEqual(list(to_list_view(self.triples_111, node=True, path=True, value=True)),
+            [123])
+        self.assertListEqual(list(to_list_view(self.triples_11U, node=True, path=True, value=True)),
+            ['tag#1234', 'tag#5678'])
+        self.assertListEqual(list(to_list_view(self.triples_1M1, node=True, path=True, value=True)),
+            [123, '2010-01-02'])
+        self.assertListEqual(list(to_list_view(self.triples_1MU, node=True, path=True, value=True)),
+            [123, 'tag#1234', 'tag#5678'])
+        self.assertListEqual(list(to_list_view(self.triples_N11, node=True, path=True, value=True)),
+            [123, 321])
+        self.assertListEqual(list(to_list_view(self.triples_N1U, node=True, path=True, value=True)),
+            ['tag#1234', 'tag#5678', 'tag#4321'])
+        self.assertListEqual(list(to_list_view(self.triples_NM1, node=True, path=True, value=True)),
+            [123, '2010-01-02', 321, '2022-02-22'])
+        self.assertListEqual(list(to_list_view(self.triples_NMU, node=True, path=True, value=True)),
+            [123, 'tag#1234', 'tag#5678', 321, '2022-02-22'])
+
+
+class TestDictView(unittest.TestCase):
+    def setUp(self):
+        self.unique_paths = {ns.bse.iso, ns.bse.t_created}
+        self.triples_111 = [('ent#1234', ns.bse.iso, 123)]
+        self.triples_11U = [('ent#1234', ns.bse.tag, 'tag#1234'),
+                            ('ent#1234', ns.bse.tag, 'tag#5678')]
+        self.triples_1M1 = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#1234', ns.bse.t_created, '2010-01-02')]
+        self.triples_1MU = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#1234', ns.bse.tag, 'tag#1234'),
+                            ('ent#1234', ns.bse.tag, 'tag#5678')]
+        self.triples_N11 = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#4321', ns.bse.iso, 321)]
+        self.triples_N1U = [('ent#1234', ns.bse.tag, 'tag#1234'),
+                            ('ent#1234', ns.bse.tag, 'tag#5678'),
+                            ('ent#4321', ns.bse.tag, 'tag#4321')]
+        self.triples_NM1 = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#1234', ns.bse.t_created, '2010-01-02'),
+                            ('ent#4321', ns.bse.iso, 321),
+                            ('ent#4321', ns.bse.t_created, '2022-02-22')]
+        self.triples_NMU = [('ent#1234', ns.bse.iso, 123),
+                            ('ent#1234', ns.bse.tag, 'tag#1234'),
+                            ('ent#1234', ns.bse.tag, 'tag#5678'),
+                            ('ent#4321', ns.bse.iso, 321),
+                            ('ent#4321', ns.bse.t_created, '2022-02-22')]
+
+    def test_errounous_call(self):
+        # return set instead of value
+        self.assertSetEqual(to_dict_view(self.triples_111, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=True, path=True, value=True),
+            {123})
+        self.assertSetEqual(to_dict_view(self.triples_111, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=True, path=True, value=True),
+            {123})
+        # one_node mismatch: return set of values instead of value
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=False, one_path=True, unique_paths=self.unique_paths, node=True, path=False, value=True),
+            {ns.bse.iso: {123}})
+        # one_path mismatch: return set of values instead of value
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True, one_path=False, unique_paths=self.unique_paths, node=False, path=True, value=True),
+            {'ent#1234': {123}})
+        # unique_paths mismatch: return set of values instead of value
+        self.assertSetEqual(to_dict_view(self.triples_111, one_node=True, one_path=False, unique_paths={}, node=True, path=True, value=True),
+            {123})
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True, one_path=False, unique_paths={}, node=True, path=False, value=True),
+            {ns.bse.iso: {123}})
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True, one_path=False, unique_paths={}, node=False, path=True, value=True),
+            {'ent#1234': {123}})
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True, one_path=False, unique_paths={}, node=False, path=False, value=True),
+            {'ent#1234': {ns.bse.iso: {123}}})
+
+    def test_agg_none(self):
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=False, path=False, value=False),
+            {'ent#1234': {ns.bse.iso: {123}}})
+        self.assertDictEqual(to_dict_view(self.triples_11U, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=False, path=False, value=False),
+            {'ent#1234': {ns.bse.tag: {'tag#1234', 'tag#5678'}}})
+        self.assertDictEqual(to_dict_view(self.triples_1M1, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=False, path=False, value=False),
+            {'ent#1234': {ns.bse.iso: {123}, ns.bse.t_created: {'2010-01-02'}}})
+        self.assertDictEqual(to_dict_view(self.triples_1MU, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=False, path=False, value=False),
+            {'ent#1234': {ns.bse.iso: {123}, ns.bse.tag: {'tag#1234', 'tag#5678'}}})
+        self.assertDictEqual(to_dict_view(self.triples_N11, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=False, path=False, value=False),
+            {'ent#1234': {ns.bse.iso: {123}}, 'ent#4321': {ns.bse.iso: {321}}})
+        self.assertDictEqual(to_dict_view(self.triples_N1U, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=False, path=False, value=False),
+            {'ent#1234': {ns.bse.tag: {'tag#1234', 'tag#5678'}}, 'ent#4321': {ns.bse.tag: {'tag#4321'}}})
+        self.assertDictEqual(to_dict_view(self.triples_NM1, one_node=False, one_path=False, unique_paths=self.unique_paths, node=False, path=False, value=False),
+            {'ent#1234': {ns.bse.iso: {123}, ns.bse.t_created: {'2010-01-02'}}, 'ent#4321': {ns.bse.iso: {321}, ns.bse.t_created: {'2022-02-22'}}})
+        self.assertDictEqual(to_dict_view(self.triples_NMU, one_node=False, one_path=False, unique_paths=self.unique_paths, node=False, path=False, value=False),
+            {'ent#1234': {ns.bse.iso: {123}, ns.bse.tag: {'tag#1234', 'tag#5678'}}, 'ent#4321': {ns.bse.iso: {321}, ns.bse.t_created: {'2022-02-22'}}})
+
+    def test_agg_node(self):
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=True, path=False, value=False),
+            {ns.bse.iso: {123}})
+        self.assertDictEqual(to_dict_view(self.triples_11U, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=True, path=False, value=False),
+            {ns.bse.tag: {'tag#1234', 'tag#5678'}})
+        self.assertDictEqual(to_dict_view(self.triples_1M1, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=True, path=False, value=False),
+            {ns.bse.iso: {123}, ns.bse.t_created: {'2010-01-02'}})
+        self.assertDictEqual(to_dict_view(self.triples_1MU, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=True, path=False, value=False),
+            {ns.bse.iso: {123}, ns.bse.tag: {'tag#1234', 'tag#5678'}})
+        self.assertDictEqual(to_dict_view(self.triples_N11, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=True, path=False, value=False),
+            {ns.bse.iso: {123, 321}})
+        self.assertDictEqual(to_dict_view(self.triples_N1U, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=True, path=False, value=False),
+            {ns.bse.tag: {'tag#1234', 'tag#5678', 'tag#4321'}})
+        self.assertDictEqual(to_dict_view(self.triples_NM1, one_node=False, one_path=False, unique_paths=self.unique_paths, node=True, path=False, value=False),
+            {ns.bse.iso: {123, 321}, ns.bse.t_created: {'2010-01-02', '2022-02-22'}})
+        self.assertDictEqual(to_dict_view(self.triples_NMU, one_node=False, one_path=False, unique_paths=self.unique_paths, node=True, path=False, value=False),
+            {ns.bse.iso: {123, 321}, ns.bse.tag: {'tag#1234', 'tag#5678'}, ns.bse.t_created: {'2022-02-22'}})
+
+    def test_agg_path(self):
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=False, path=True, value=False),
+            {'ent#1234': {123}})
+        self.assertDictEqual(to_dict_view(self.triples_11U, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=False, path=True, value=False),
+            {'ent#1234': {'tag#1234', 'tag#5678'}})
+        self.assertDictEqual(to_dict_view(self.triples_1M1, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=False, path=True, value=False),
+            {'ent#1234': {123, '2010-01-02'}})
+        self.assertDictEqual(to_dict_view(self.triples_1MU, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=False, path=True, value=False),
+            {'ent#1234': {123, 'tag#1234', 'tag#5678'}})
+        self.assertDictEqual(to_dict_view(self.triples_N11, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=False, path=True, value=False),
+            {'ent#1234': {123}, 'ent#4321': {321}})
+        self.assertDictEqual(to_dict_view(self.triples_N1U, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=False, path=True, value=False),
+            {'ent#1234': {'tag#1234', 'tag#5678'}, 'ent#4321': {'tag#4321'}})
+        self.assertDictEqual(to_dict_view(self.triples_NM1, one_node=False, one_path=False, unique_paths=self.unique_paths, node=False, path=True, value=False),
+            {'ent#1234': {123, '2010-01-02'}, 'ent#4321': {321, '2022-02-22'}})
+        self.assertDictEqual(to_dict_view(self.triples_NMU, one_node=False, one_path=False, unique_paths=self.unique_paths, node=False, path=True, value=False),
+            {'ent#1234': {123, 'tag#1234', 'tag#5678'}, 'ent#4321': {321, '2022-02-22'}})
+
+    def test_agg_node_path(self):
+        self.assertSetEqual(to_dict_view(self.triples_111, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=True, path=True, value=False),
+            {123})
+        self.assertSetEqual(to_dict_view(self.triples_11U, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=True, path=True, value=False),
+            {'tag#1234', 'tag#5678'})
+        self.assertSetEqual(to_dict_view(self.triples_1M1, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=True, path=True, value=False),
+            {123, '2010-01-02'})
+        self.assertSetEqual(to_dict_view(self.triples_1MU, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=True, path=True, value=False),
+            {123, 'tag#1234', 'tag#5678'})
+        self.assertSetEqual(to_dict_view(self.triples_N11, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=True, path=True, value=False),
+            {123, 321})
+        self.assertSetEqual(to_dict_view(self.triples_N1U, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=True, path=True, value=False),
+            {'tag#1234', 'tag#5678', 'tag#4321'})
+        self.assertSetEqual(to_dict_view(self.triples_NM1, one_node=False, one_path=False, unique_paths=self.unique_paths, node=True, path=True, value=False),
+            {123, '2010-01-02', 321, '2022-02-22'})
+        self.assertSetEqual(to_dict_view(self.triples_NMU, one_node=False, one_path=False, unique_paths=self.unique_paths, node=True, path=True, value=False),
+            {123, 'tag#1234', 'tag#5678', 321, '2022-02-22'})
+
+    def test_agg_value(self):
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=False, path=False, value=True),
+            {'ent#1234': {ns.bse.iso: 123}})
+        self.assertDictEqual(to_dict_view(self.triples_11U, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=False, path=False, value=True),
+            {'ent#1234': {ns.bse.tag: {'tag#1234', 'tag#5678'}}})
+        self.assertDictEqual(to_dict_view(self.triples_1M1, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=False, path=False, value=True),
+            {'ent#1234': {ns.bse.iso: 123, ns.bse.t_created: '2010-01-02'}})
+        self.assertDictEqual(to_dict_view(self.triples_1MU, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=False, path=False, value=True),
+            {'ent#1234': {ns.bse.iso: 123, ns.bse.tag: {'tag#1234', 'tag#5678'}}})
+        self.assertDictEqual(to_dict_view(self.triples_N11, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=False, path=False, value=True),
+            {'ent#1234': {ns.bse.iso: 123}, 'ent#4321': {ns.bse.iso: 321}})
+        self.assertDictEqual(to_dict_view(self.triples_N1U, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=False, path=False, value=True),
+            {'ent#1234': {ns.bse.tag: {'tag#1234', 'tag#5678'}}, 'ent#4321': {ns.bse.tag: {'tag#4321'}}})
+        self.assertDictEqual(to_dict_view(self.triples_NM1, one_node=False, one_path=False, unique_paths=self.unique_paths, node=False, path=False, value=True),
+            {'ent#1234': {ns.bse.iso: 123, ns.bse.t_created: '2010-01-02'}, 'ent#4321': {ns.bse.iso: 321, ns.bse.t_created: '2022-02-22'}})
+        self.assertDictEqual(to_dict_view(self.triples_NMU, one_node=False, one_path=False, unique_paths=self.unique_paths, node=False, path=False, value=True),
+            {'ent#1234': {ns.bse.iso: 123, ns.bse.tag: {'tag#1234', 'tag#5678'}}, 'ent#4321': {ns.bse.iso: 321, ns.bse.t_created: '2022-02-22'}})
+
+    def test_agg_node_value(self):
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=True, path=False, value=True),
+            {ns.bse.iso: 123})
+        self.assertDictEqual(to_dict_view(self.triples_11U, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=True, path=False, value=True),
+            {ns.bse.tag: {'tag#1234', 'tag#5678'}})
+        self.assertDictEqual(to_dict_view(self.triples_1M1, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=True, path=False, value=True),
+            {ns.bse.iso: 123, ns.bse.t_created: '2010-01-02'})
+        self.assertDictEqual(to_dict_view(self.triples_1MU, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=True, path=False, value=True),
+            {ns.bse.iso: 123, ns.bse.tag: {'tag#1234', 'tag#5678'}})
+        self.assertDictEqual(to_dict_view(self.triples_N11, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=True, path=False, value=True),
+            {ns.bse.iso: {123, 321}})
+        self.assertDictEqual(to_dict_view(self.triples_N1U, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=True, path=False, value=True),
+            {ns.bse.tag: {'tag#1234', 'tag#5678', 'tag#4321'}})
+        self.assertDictEqual(to_dict_view(self.triples_NM1, one_node=False, one_path=False, unique_paths=self.unique_paths, node=True, path=False, value=True),
+            {ns.bse.iso: {123, 321}, ns.bse.t_created: {'2010-01-02', '2022-02-22'}})
+        self.assertDictEqual(to_dict_view(self.triples_NMU, one_node=False, one_path=False, unique_paths=self.unique_paths, node=True, path=False, value=True),
+            {ns.bse.iso: {123, 321}, ns.bse.tag: {'tag#1234', 'tag#5678'}, ns.bse.t_created: {'2022-02-22'}})
+
+    def test_agg_path_value(self):
+        self.assertDictEqual(to_dict_view(self.triples_111, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=False, path=True, value=True),
+            {'ent#1234': 123})
+        self.assertDictEqual(to_dict_view(self.triples_11U, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=False, path=True, value=True),
+            {'ent#1234': {'tag#1234', 'tag#5678'}})
+        self.assertDictEqual(to_dict_view(self.triples_1M1, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=False, path=True, value=True),
+            {'ent#1234': {123, '2010-01-02'}})
+        self.assertDictEqual(to_dict_view(self.triples_1MU, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=False, path=True, value=True),
+            {'ent#1234': {123, 'tag#1234', 'tag#5678'}})
+        self.assertDictEqual(to_dict_view(self.triples_N11, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=False, path=True, value=True),
+            {'ent#1234': 123, 'ent#4321': 321})
+        self.assertDictEqual(to_dict_view(self.triples_N1U, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=False, path=True, value=True),
+            {'ent#1234': {'tag#1234', 'tag#5678'}, 'ent#4321': {'tag#4321'}})
+        self.assertDictEqual(to_dict_view(self.triples_NM1, one_node=False, one_path=False, unique_paths=self.unique_paths, node=False, path=True, value=True),
+            {'ent#1234': {123, '2010-01-02'}, 'ent#4321': {321, '2022-02-22'}})
+        self.assertDictEqual(to_dict_view(self.triples_NMU, one_node=False, one_path=False, unique_paths=self.unique_paths, node=False, path=True, value=True),
+            {'ent#1234': {123, 'tag#1234', 'tag#5678'}, 'ent#4321': {321, '2022-02-22'}})
+
+    def test_agg_all(self):
+        self.assertEqual(to_dict_view(self.triples_111, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=True, path=True, value=True),
+            123)
+        self.assertSetEqual(to_dict_view(self.triples_11U, one_node=True,  one_path=True,  unique_paths=self.unique_paths, node=True, path=True, value=True),
+            {'tag#1234', 'tag#5678'})
+        self.assertSetEqual(to_dict_view(self.triples_1M1, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=True, path=True, value=True),
+            {123, '2010-01-02'})
+        self.assertSetEqual(to_dict_view(self.triples_1MU, one_node=True,  one_path=False, unique_paths=self.unique_paths, node=True, path=True, value=True),
+            {123, 'tag#1234', 'tag#5678'})
+        self.assertSetEqual(to_dict_view(self.triples_N11, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=True, path=True, value=True),
+            {123, 321})
+        self.assertSetEqual(to_dict_view(self.triples_N1U, one_node=False, one_path=True,  unique_paths=self.unique_paths, node=True, path=True, value=True),
+            {'tag#1234', 'tag#5678', 'tag#4321'})
+        self.assertSetEqual(to_dict_view(self.triples_NM1, one_node=False, one_path=False, unique_paths=self.unique_paths, node=True, path=True, value=True),
+            {123, '2010-01-02', 321, '2022-02-22'})
+        self.assertSetEqual(to_dict_view(self.triples_NMU, one_node=False, one_path=False, unique_paths=self.unique_paths, node=True, path=True, value=True),
+            {123, 'tag#1234', 'tag#5678', 321, '2022-02-22'})
+
+
+## main ##
+
+if __name__ == '__main__':
+    unittest.main()
+
+## EOF ##