diff --git a/test/test_decimals.py b/test/test_decimals.py
new file mode 100644
index 0000000..e2e4b8e
--- /dev/null
+++ b/test/test_decimals.py
@@ -0,0 +1,180 @@
+# -*- coding: utf-8 -*-
+#
+
+# This software was developed at the National Institute of Standards
+# and Technology by employees of the Federal Government in the course
+# of their official duties. Pursuant to title 17 Section 105 of the
+# United States Code this software is not subject to copyright
+# protection and is in the public domain. NIST assumes no
+# responsibility whatsoever for its use by other parties, and makes
+# no guarantees, expressed or implied, about its quality,
+# reliability, or any other characteristic.
+#
+# We would appreciate acknowledgement if the software is used.
+
+"""
+Test that values declared as XSD decimal type are confirmed to be conformant with datatype constraints.
+
+_PASS and _XFAIL name portions on tests in this script denote whether the input data graph should have a True or False conformance result.
+"""
+
+from rdflib import Graph, RDF, SH
+
+from pyshacl import validate
+
+ontology_file_text = """
+@prefix owl: <http://www.w3.org/2002/07/owl#> .
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix exOnt: <http://example.com/exOnt#> .
+
+<http://example.com/exOnt> a owl:Ontology ;
+    rdfs:label "An example extra-ontology file."@en .
+
+exOnt:NumberHolder a owl:Class .
+
+exOnt:propBoolean a owl:DatatypeProperty ;
+    rdfs:domain exOnt:NumberHolder ;
+    rdfs:range xsd:boolean .
+
+exOnt:propDecimal a owl:DatatypeProperty ;
+    rdfs:domain exOnt:NumberHolder ;
+    rdfs:range xsd:decimal .
+"""
+
+shacl_file_text = """
+@prefix owl: <http://www.w3.org/2002/07/owl#> .
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix sh: <http://www.w3.org/ns/shacl#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix exShape: <http://example.com/exShape#> .
+@prefix exOnt: <http://example.com/exOnt#> .
+
+<http://example.com/exShape> a owl:Ontology ;
+    rdfs:label "Example Shapes File"@en .
+
+exShape:NumberHolderShape
+    sh:property
+        [
+            sh:datatype xsd:boolean ;
+            sh:path exOnt:propBoolean ;
+        ] ,
+        [
+            sh:datatype xsd:decimal ;
+            sh:path exOnt:propDecimal ;
+        ] ;
+    sh:targetClass exOnt:NumberHolder ;
+    .
+"""
+
+data_file_text_PASS = """
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix exOnt: <http://example.com/exOnt#> .
+@prefix ex: <http://example.com/ex#> .
+
+ex:holder0 a exOnt:NumberHolder ;
+    exOnt:propDecimal
+      "1"^^xsd:decimal ,
+      "2."^^xsd:decimal ,
+      "3.4"^^xsd:decimal ,
+      "5.6666666666666666667"^^xsd:decimal ,
+      "-8"^^xsd:decimal ,
+      "-9."^^xsd:decimal ,
+      "-0."^^xsd:decimal ;
+    .
+"""
+
+
+def test_validate_with_ontology() -> None:
+    g = Graph().parse(data=data_file_text_PASS, format='turtle')
+    e = Graph().parse(data=ontology_file_text, format='turtle')
+    g_len = len(g)
+    res = validate(
+        g, shacl_graph=shacl_file_text, shacl_graph_format='turtle', ont_graph=e, inference='both', debug=True
+    )
+    conforms, graph, string = res
+    g_len2 = len(g)
+    assert conforms
+    assert g_len2 == g_len
+
+
+data_file_text_XFAIL_unrelated = """
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix exOnt: <http://example.com/exOnt#> .
+@prefix ex: <http://example.com/ex#> .
+
+ex:holder1 a exOnt:NumberHolder ;
+    exOnt:propBoolean
+      "Not boolean" ;
+    exOnt:propDecimal
+      "1"^^xsd:decimal ,
+      "2."^^xsd:decimal ,
+      "3.4"^^xsd:decimal ,
+      "5.67"^^xsd:decimal ,
+      "-8"^^xsd:decimal ,
+      "-9."^^xsd:decimal ,
+      "-0."^^xsd:decimal ;
+    .
+"""
+
+
+def test_validate_with_ontology_XFAIL_unrelated() -> None:
+    res = validate(
+        data_file_text_XFAIL_unrelated,
+        shacl_graph=shacl_file_text,
+        data_graph_format='turtle',
+        shacl_graph_format='turtle',
+        ont_graph=ontology_file_text,
+        ont_graph_format="turtle",
+        inference="both",
+        debug=True,
+    )
+    conforms, graph, string = res
+    validation_result_tally = 0
+    for triple in graph.triples((None, RDF.type, SH.ValidationResult)):
+        validation_result_tally += 1
+    assert not conforms
+    assert validation_result_tally == 1
+
+
+data_file_text_XFAIL_lexical_space = """
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix exOnt: <http://example.com/exOnt#> .
+@prefix ex: <http://example.com/ex#> .
+
+ex:holder2 a exOnt:NumberHolder ;
+    rdfs:comment "Each value has an error.  All values use an invalid lexical value."@en ;
+    rdfs:seeAlso <https://www.w3.org/TR/turtle/#abbrev> ;
+    exOnt:propDecimal
+      "1.."^^xsd:decimal ,
+      "2.3."^^xsd:decimal ,
+      "4a"^^xsd:decimal ,
+      "5x"^^xsd:decimal ,
+      "6y."^^xsd:decimal ;
+    .
+"""
+
+
+def test_validate_with_ontology_XFAIL_lexical_space() -> None:
+    res = validate(
+        data_file_text_XFAIL_lexical_space,
+        shacl_graph=shacl_file_text,
+        data_graph_format='turtle',
+        shacl_graph_format='turtle',
+        ont_graph=ontology_file_text,
+        ont_graph_format="turtle",
+        inference="both",
+        debug=True,
+    )
+    conforms, graph, string = res
+    validation_result_tally = 0
+    for triple in graph.triples((None, RDF.type, SH.ValidationResult)):
+        validation_result_tally += 1
+    assert not conforms
+    assert validation_result_tally == 5