diff --git a/test/test_graph/test_aggregate_graphs.py b/test/test_graph/test_aggregate_graphs.py
index fd45c4a14..6ede92fda 100644
--- a/test/test_graph/test_aggregate_graphs.py
+++ b/test/test_graph/test_aggregate_graphs.py
@@ -1,7 +1,7 @@
 from io import StringIO
 
-from rdflib import logger, plugin
-from rdflib.graph import ConjunctiveGraph, Graph, ReadOnlyGraphAggregate
+from rdflib import Dataset, Graph, logger, plugin
+from rdflib.graph import ReadOnlyGraphAggregate
 from rdflib.namespace import RDF, RDFS
 from rdflib.store import Store
 from rdflib.term import URIRef
@@ -108,10 +108,10 @@ def test_aggregate2():
 
     graph4 = Graph(mem_store, RDFS)
     graph4.parse(data=TEST_GRAPH_1N3, format="n3")
-    g = ConjunctiveGraph(mem_store)
+    g = Dataset(store=mem_store, default_union=True)
     assert g is not None
     assert len(list(g.quads((None, None, None, None)))) == 11
-    assert len(list(g.contexts())) == 4
+    assert len(list(g.contexts())) == 5
     logger.debug(list(g.contexts()))
     assert (
         len(list(g.quads((None, None, None, URIRef("http://example.com/graph2"))))) == 4
diff --git a/test/test_graph/test_graph_context.py b/test/test_graph/test_graph_context.py
index 8c1a8a457..93c5f7d9b 100644
--- a/test/test_graph/test_graph_context.py
+++ b/test/test_graph/test_graph_context.py
@@ -9,7 +9,7 @@
 
 import pytest
 
-from rdflib import BNode, ConjunctiveGraph, Graph, URIRef, plugin
+from rdflib import BNode, Dataset, Graph, URIRef, plugin
 from rdflib.store import Store
 
 
@@ -20,7 +20,7 @@ class ContextTestCase(unittest.TestCase):
 
     def setUp(self):
         try:
-            self.graph = ConjunctiveGraph(store=self.store)
+            self.graph = Dataset(store=self.store, default_union=True)
         except ImportError:
             pytest.skip("Dependencies for store '%s' not available!" % self.store)
         if self.store == "SQLite":
@@ -337,8 +337,11 @@ def test_triples(self):
             )
             asserte(set(c.subject_predicates(michel)), {(bob, hates)})
 
+            d = set()
+            for x in c:
+                d.add(x[0:3])
             asserte(
-                set(c),
+                set(d),
                 {
                     (bob, hates, michel),
                     (bob, likes, cheese),
diff --git a/test/test_issues/test_issue535.py b/test/test_issues/test_issue535.py
index 03f75d601..80a639694 100644
--- a/test/test_issues/test_issue535.py
+++ b/test/test_issues/test_issue535.py
@@ -1,8 +1,8 @@
-from rdflib import ConjunctiveGraph, URIRef
+from rdflib import Dataset, URIRef
 
 
 def test_nquads_default_graph():
-    ds = ConjunctiveGraph()
+    ds = Dataset(default_union=True)
 
     data = """
     <http://example.org/s1> <http://example.org/p1> <http://example.org/o1> .
diff --git a/test/test_namespace/test_namespace.py b/test/test_namespace/test_namespace.py
index 409d703f3..60d687424 100644
--- a/test/test_namespace/test_namespace.py
+++ b/test/test_namespace/test_namespace.py
@@ -232,7 +232,7 @@ def add_not_in_namespace(s):
         # a property name within the FOAF namespace
         assert FOAF.givenName == URIRef("http://xmlns.com/foaf/0.1/givenName")
 
-        # namescape can be used as str
+        # namespace can be used as str
         assert FOAF.givenName.startswith(FOAF)
 
     def test_contains_method(self):
diff --git a/test/test_parsers/test_broken_parse_data_from_jena.py b/test/test_parsers/test_broken_parse_data_from_jena.py
index 353593837..da25154a7 100644
--- a/test/test_parsers/test_broken_parse_data_from_jena.py
+++ b/test/test_parsers/test_broken_parse_data_from_jena.py
@@ -33,6 +33,6 @@ def xfail_broken_parse_data(request):
 @pytest.mark.parametrize("testfile", os.listdir(broken_parse_data))
 @pytest.mark.usefixtures("xfail_broken_parse_data")
 def test_n3_serializer_roundtrip(testfile) -> None:
-    g1 = rdflib.ConjunctiveGraph()
+    g1 = rdflib.Dataset(default_union=True)
 
     g1.parse(os.path.join(broken_parse_data, testfile), format="n3")
diff --git a/test/test_serializers/test_prettyxml.py b/test/test_serializers/test_prettyxml.py
index 6c798e825..aac19af50 100644
--- a/test/test_serializers/test_prettyxml.py
+++ b/test/test_serializers/test_prettyxml.py
@@ -1,6 +1,6 @@
 from io import BytesIO
 
-from rdflib.graph import ConjunctiveGraph
+from rdflib.graph import Dataset
 from rdflib.namespace import RDF, RDFS
 from rdflib.plugins.serializers.rdfxml import PrettyXMLSerializer
 from rdflib.term import BNode, Literal, URIRef
@@ -10,7 +10,7 @@ class SerializerTestBase:
     repeats = 8
 
     def setup_method(self):
-        graph = ConjunctiveGraph()
+        graph = Dataset()
         graph.parse(data=self.test_content, format=self.test_content_format)
         self.source_graph = graph
 
@@ -41,12 +41,12 @@ def _assert_equal_graphs(g1, g2):
 
 def _mangled_copy(g):
     "Makes a copy of the graph, replacing all bnodes with the bnode ``_blank``."
-    gcopy = ConjunctiveGraph()
+    gcopy = Dataset()
 
     def isbnode(v):
         return isinstance(v, BNode)
 
-    for s, p, o in g:
+    for s, p, o, c in g:
         if isbnode(s):
             s = _blank
         if isbnode(p):
@@ -67,7 +67,7 @@ def serialize(source_graph, make_serializer, get_value=True, extra_args={}):
 def serialize_and_load(source_graph, make_serializer):
     stream = serialize(source_graph, make_serializer, False)
     stream.seek(0)
-    reparsed_graph = ConjunctiveGraph()
+    reparsed_graph = Dataset()
     reparsed_graph.parse(stream, format="xml")
     return reparsed_graph
 
@@ -170,7 +170,7 @@ def test_subclass_of_objects(self):
 
     def test_pretty_xmlliteral(self):
         # given:
-        g = ConjunctiveGraph()
+        g = Dataset()
         g.add(
             (
                 BNode(),
@@ -191,7 +191,7 @@ def test_pretty_xmlliteral(self):
 
     def test_pretty_broken_xmlliteral(self):
         # given:
-        g = ConjunctiveGraph()
+        g = Dataset()
         g.add((BNode(), RDF.value, Literal("""<p """, datatype=RDF.XMLLiteral)))
         # when:
         xmlrepr = g.serialize(format="pretty-xml")
@@ -203,7 +203,7 @@ def test_pretty_broken_xmlliteral(self):
 
 
 def _assert_expected_object_types_for_predicates(graph, predicates, types):
-    for s, p, o in graph:
+    for s, p, o, c in graph:
         if p in predicates:
             some_true = [isinstance(o, t) for t in types]
             assert (
diff --git a/test/test_serializers/test_serializer.py b/test/test_serializers/test_serializer.py
index 6fab945f3..096142dc1 100644
--- a/test/test_serializers/test_serializer.py
+++ b/test/test_serializers/test_serializer.py
@@ -30,7 +30,7 @@
 import rdflib
 import rdflib.plugin
 from rdflib import RDF, XSD, Graph, Literal, Namespace, URIRef
-from rdflib.graph import DATASET_DEFAULT_GRAPH_ID, ConjunctiveGraph, Dataset
+from rdflib.graph import DATASET_DEFAULT_GRAPH_ID, Dataset
 from rdflib.serializer import Serializer
 from test.utils import GraphHelper, get_unique_plugins
 from test.utils.destination import DestinationType, DestParmType, DestRef
@@ -54,7 +54,7 @@
 )
 def test_rdf_type(format: str, tuple_index: int, is_keyword: bool) -> None:
     NS = Namespace("example:")  # noqa: N806
-    graph = ConjunctiveGraph()
+    graph = Dataset(default_union=True)
     graph.bind("eg", NS)
     nodes = [NS.subj, NS.pred, NS.obj, NS.graph]
     nodes[tuple_index] = RDF.type
@@ -68,7 +68,7 @@ def test_rdf_type(format: str, tuple_index: int, is_keyword: bool) -> None:
         assert str(RDF) not in data
     else:
         assert str(RDF) in data
-    parsed_graph = ConjunctiveGraph()
+    parsed_graph = Dataset(default_union=True)
     parsed_graph.parse(data=data, format=format)
     GraphHelper.assert_triple_sets_equals(graph, parsed_graph)
 
diff --git a/test/test_store/test_store_sparqlupdatestore_mock.py b/test/test_store/test_store_sparqlupdatestore_mock.py
index 5d7e13eb8..054f746e1 100644
--- a/test/test_store/test_store_sparqlupdatestore_mock.py
+++ b/test/test_store/test_store_sparqlupdatestore_mock.py
@@ -1,6 +1,6 @@
 from typing import ClassVar
 
-from rdflib.graph import ConjunctiveGraph
+from rdflib.graph import Dataset
 from rdflib.plugins.stores.sparqlstore import SPARQLUpdateStore
 from test.utils.http import MethodName, MockHTTPResponse
 from test.utils.httpservermock import ServedBaseHTTPServerMock
@@ -33,7 +33,7 @@ def teardown_method(self):
         pass
 
     def test_graph_update(self):
-        graph = ConjunctiveGraph("SPARQLUpdateStore")
+        graph = Dataset("SPARQLUpdateStore")
         graph.open((self.query_endpoint, self.update_endpoint))
         update_statement = (
             f"INSERT DATA {{ {EGDO['subj']} {EGDO['pred']} {EGDO['obj']}. }}"
@@ -58,7 +58,7 @@ def test_graph_update(self):
         assert "application/sparql-update" in req.headers.get("content-type")
 
     def test_update_encoding(self):
-        graph = ConjunctiveGraph("SPARQLUpdateStore")
+        graph = Dataset("SPARQLUpdateStore")
         graph.open((self.query_endpoint, self.update_endpoint))
         update_statement = (
             f"INSERT DATA {{ {EGDO['subj']} {EGDO['pred']} {EGDO['obj']}. }}"