diff --git a/src/ifctester/ifctester/facet.py b/src/ifctester/ifctester/facet.py
index 7d6a8588db..1b5660dcb8 100644
--- a/src/ifctester/ifctester/facet.py
+++ b/src/ifctester/ifctester/facet.py
@@ -106,6 +106,14 @@ class Facet:
             raise Exception(str(parameter) + " was not able to be converted into 'Parameter_dict'")
         return parameter_dict
 
+    def get_usage(self):
+        if self.minOccurs != 0:
+            return "required"
+        elif self.minOccurs == 0 and self.maxOccurs != 0:
+            return "optional"
+        elif self.maxOccurs == 0:
+            return "prohibited"
+
 
 class Entity(Facet):
     def __init__(self, name="IFCWALL", predefinedType=None, instructions=None):
@@ -165,24 +173,11 @@ class Attribute(Facet):
         if self.minOccurs == 0 and self.maxOccurs != 0:
             return AttributeResult(True)
 
-        def get_values(element, name):
-            if isinstance(name, str):
-                return [getattr(element, name, None)]
-            return [v for k, v in element.get_info().items() if k == name]
-
-        element_type = ifcopenshell.util.element.get_type(inst)
-
         if isinstance(self.name, str):
-            type_value = getattr(element_type, self.name, None) if element_type else None
-            occurrence_value = getattr(inst, self.name, None)
             names = [self.name]
-            values = [occurrence_value if occurrence_value is not None else type_value]
+            values = [getattr(inst, self.name, None)]
         else:
-            if element_type:
-                info = element_type.get_info()
-                info.update({k: v for k, v in inst.get_info().items() if v is not None})
-            else:
-                info = inst.get_info()
+            info = inst.get_info()
             names = []
             values = []
             for k, v in info.items():
@@ -197,29 +192,31 @@ class Attribute(Facet):
             reason = {"type": "NOVALUE"}
 
         if is_pass:
+            non_empty_values = []
             for i, value in enumerate(values):
+                is_empty = False
                 if value is None:
-                    is_pass = False
-                    reason = {"type": "FALSEY", "actual": value}
+                    is_empty = True
                 elif value == "":
-                    is_pass = False
-                    reason = {"type": "FALSEY", "actual": value}
+                    is_empty = True
                 elif value == tuple():
-                    is_pass = False
-                    reason = {"type": "FALSEY", "actual": value}
+                    is_empty = True
                 else:
                     argument_index = inst.wrapped_data.get_argument_index(names[i])
                     try:
                         attribute_type = inst.attribute_type(argument_index)
                         if attribute_type == "LOGICAL" and value == "UNKNOWN":
-                            is_pass = False
-                            reason = {"type": "FALSEY", "actual": value}
+                            is_empty = True
                     except:
                         if names[i] in inst.wrapped_data.get_inverse_attribute_names():
-                            is_pass = False
-                            reason = {"type": "INVALID"}
-                if not is_pass:
-                    break
+                            is_empty = True
+                if not is_empty:
+                    non_empty_values.append(value)
+            if non_empty_values:
+                values = non_empty_values
+            else:
+                is_pass = False
+                reason = {"type": "FALSEY", "actual": values if len(values) > 1 else values[0]}
 
         if is_pass and self.value:
             for value in values:
@@ -326,7 +323,7 @@ class PartOf(Facet):
             aggregate = ifcopenshell.util.element.get_aggregate(inst)
             is_pass = aggregate is not None
             if not is_pass:
-                reason = {"type": "RELATION"}
+                reason = {"type": "NOVALUE"}
             if is_pass and self.entity:
                 is_pass = False
                 ancestors = []
@@ -355,7 +352,7 @@ class PartOf(Facet):
             container = ifcopenshell.util.element.get_container(inst)
             is_pass = container is not None
             if not is_pass:
-                reason = {"type": "RELATION"}
+                reason = {"type": "NOVALUE"}
             if is_pass and self.entity:
                 if container.is_a().upper() != self.entity:
                     is_pass = False
@@ -871,6 +868,8 @@ class AttributeResult(Result):
             return f"An invalid attribute name was specified in the IDS"
         elif self.reason["type"] == "VALUE":
             return f"The attribute value \"{str(self.reason['actual'])}\" does not match the requirement"
+        elif self.reason["type"] == "PROHIBITED":
+            return f"The attribute value should not have met the requirement"
 
 
 class ClassificationResult(Result):
@@ -881,11 +880,18 @@ class ClassificationResult(Result):
             return f"The references \"{str(self.reason['actual'])}\" do not match the requirements"
         elif self.reason["type"] == "system":
             return f"The systems \"{str(self.reason['actual'])}\" do not match the requirements"
+        elif self.reason["type"] == "PROHIBITED":
+            return f"The classification should not have met the requirement"
 
 
 class PartOfResult(Result):
     def to_string(self):
-        return "TODO"
+        if self.reason["type"] == "NOVALUE":
+            return "The entity has no relationship"
+        elif self.reason["type"] == "ENTITY":
+            return f"The entity has a relationship with incorrect entities: \"{str(self.reason['actual'])}\""
+        elif self.reason["type"] == "PROHIBITED":
+            return f"The relationship should not have met the requirement"
 
 
 class PropertyResult(Result):
@@ -900,6 +906,8 @@ class PropertyResult(Result):
             return f"The property value \"{str(self.reason['actual'][0])}\" does not match the requirements"
         elif self.reason["type"] == "VALUE":
             return f"The property values \"{str(self.reason['actual'])}\" do not match the requirements"
+        elif self.reason["type"] == "PROHIBITED":
+            return f"The property should not have met the requirement"
 
 
 class MaterialResult(Result):
@@ -910,3 +918,5 @@ class MaterialResult(Result):
             return (
                 f"The material names and categories of \"{str(self.reason['actual'])}\" does not match the requirement"
             )
+        elif self.reason["type"] == "PROHIBITED":
+            return f"The material should not have met the requirement"
diff --git a/src/ifctester/ifctester/ids.py b/src/ifctester/ifctester/ids.py
index b8a8cbb722..35c1ea18c2 100644
--- a/src/ifctester/ifctester/ids.py
+++ b/src/ifctester/ifctester/ids.py
@@ -32,9 +32,7 @@ def open(filepath, validate=False):
     if validate:
         get_schema().validate(filepath)
     return Ids().parse(
-        get_schema().decode(
-            filepath, strip_namespaces=True, namespaces={"": "http://standards.buildingsmart.org/IDS"}
-        )
+        get_schema().decode(filepath, strip_namespaces=True, namespaces={"": "http://standards.buildingsmart.org/IDS"})
     )
 
 
@@ -114,18 +112,18 @@ class Ids:
         ET.ElementTree(get_schema().encode(self.asdict())).write(filepath, encoding="utf-8", xml_declaration=True)
         return get_schema().is_valid(filepath)
 
-    def validate(self, ifc_file):
+    def validate(self, ifc_file, filter_version=False):
         for specification in self.specifications:
             specification.reset_status()
-            specification.validate(ifc_file)
+            specification.validate(ifc_file, filter_version=filter_version)
 
 
 class Specification:
     def __init__(
         self,
         name="Unnamed",
-        minOccurs=None,
-        maxOccurs=None,
+        minOccurs=0,
+        maxOccurs="unbounded",
         ifcVersion=["IFC2X3", "IFC4"],
         identifier=None,
         description=None,
@@ -153,7 +151,7 @@ class Specification:
         }
         for attribute in ["identifier", "description", "instructions", "minOccurs", "maxOccurs"]:
             value = getattr(self, attribute)
-            if value:
+            if value is not None:
                 results[f"@{attribute}"] = value
         for clause_type in ["applicability", "requirements"]:
             clause = getattr(self, clause_type)
@@ -194,11 +192,12 @@ class Specification:
         self.applicable_entities.clear()
         self.failed_entities = set()
         for facet in self.requirements:
+            facet.status = None
             facet.failed_entities.clear()
         self.status = None
 
-    def validate(self, ifc_file):
-        if ifc_file.schema not in self.ifcVersion:
+    def validate(self, ifc_file, filter_version=False):
+        if filter_version and ifc_file.schema not in self.ifcVersion:
             return
 
         elements = []
@@ -218,18 +217,38 @@ class Specification:
             self.applicable_entities.append(element)
             for facet in self.requirements:
                 result = facet(element)
-                facet.status = bool(result)
-                if not facet.status:
+                if not bool(result):
                     self.failed_entities.add(element)
                     facet.failed_entities.append(element)
                     facet.failed_reasons.append(str(result))
 
+        for facet in self.requirements:
+            if facet.minOccurs != 0:
+                facet.status = not bool(facet.failed_entities)
+            elif facet.minOccurs == 0 and facet.maxOccurs != 0:
+                facet.status = True
+            elif facet.maxOccurs == 0:
+                facet.status = bool(facet.failed_entities)
+
         self.status = True
-        if self.failed_entities:
-            self.status = False
-        elif self.minOccurs != 0 and not self.applicable_entities:
-            self.status = False
-            for facet in self.requirements:
-                facet.status = False
-        elif len(self.applicable_entities) > (self.maxOccurs or 1):
-            self.status = False
+        if self.minOccurs != 0:
+            if not self.applicable_entities:
+                self.status = False
+                for facet in self.requirements:
+                    facet.status = False
+            elif self.failed_entities:
+                self.status = False
+        elif self.minOccurs == 0 and self.maxOccurs != 0:
+            if self.failed_entities:
+                self.status = False
+        elif self.maxOccurs == 0:
+            if (len(self.applicable_entities) - len(self.failed_entities)) > 0:
+                self.status = False
+
+    def get_usage(self):
+        if self.minOccurs != 0:
+            return "required"
+        elif self.minOccurs == 0 and self.maxOccurs != 0:
+            return "optional"
+        elif self.maxOccurs == 0:
+            return "prohibited"
diff --git a/src/ifctester/test/ids_doc_generator.py b/src/ifctester/test/ids_doc_generator.py
index 4fb16053d6..61bb8e6dc3 100644
--- a/src/ifctester/test/ids_doc_generator.py
+++ b/src/ifctester/test/ids_doc_generator.py
@@ -24,27 +24,21 @@ import functools
 import ifcopenshell
 import ifctester
 import test_facet
+import test_ids
 from xml.dom.minidom import parseString
 from ifctester import ids
 from ifcopenshell import validate
 
 outdir = "build"
 
-class StableUUIDGenerator:
-    file = None
-
-    @classmethod
-    def generate(cls):
-        ns = uuid.UUID('b59aa156-82a4-4b4c-a6e5-3d04a0236af9')
-        if cls.file:
-            return ifcopenshell.guid.compress(uuid.uuid5(ns, str(cls.file.wrapped_data.getMaxId())).hex)
-        return ifcopenshell.guid.compress(uuid.uuid4().hex)
-
 # Just for aesthetics so we don't keep on getting brand new GlobalIds on each generation
-ifcopenshell.guid.new = StableUUIDGenerator.generate
+def regenerate_guids(ifc):
+    ns = uuid.UUID("b59aa156-82a4-4b4c-a6e5-3d04a0236af9")
+    for element in ifc.by_type("IfcRoot"):
+        element.GlobalId = ifcopenshell.guid.compress(uuid.uuid5(ns, str(element.id())).hex)
 
 
-class DocGenerator:
+class FacetDocGenerator:
     def __init__(self):
         self.facet = None
         self.testcases = {}
@@ -55,12 +49,13 @@ class DocGenerator:
 
         result = "pass" if expected is True else "fail"
 
-        f = inst.wrapped_data.file
-        StableUUIDGenerator.file = f
+        ifc = inst.wrapped_data.file
+        if "GlobalId" not in name:
+            regenerate_guids(ifc)
 
         # Validate the file created and loop over the issues, fixing them one by one.
         l = validate.json_logger()
-        validate.validate(f, l)
+        validate.validate(ifc, l)
         for issue in l.statements:
             if "GlobalId" in issue["message"]:
                 issue["instance"].GlobalId = ifcopenshell.guid.new()
@@ -68,17 +63,17 @@ class DocGenerator:
                 ty = re.findall("\\(.+?\\)", issue["message"])[0][1:-1].split(", ")[0]
                 issue["instance"].PredefinedType = ty
             elif "IfcMaterialList" in issue["message"]:
-                issue["instance"].Materials = [f.createIfcMaterial("Concrete", None, "CONCRETE")]
+                issue["instance"].Materials = [ifc.createIfcMaterial("Concrete", None, "CONCRETE")]
             else:
                 raise Exception("About to emit invalid example data:", issue)
 
         # ifc_text = "\n".join([f"{e} /* Testcase */" if e == inst else str(e) for e in f])
-        lines = f.wrapped_data.to_string().split("\n")[7:-3]
+        lines = ifc.wrapped_data.to_string().split("\n")[7:-3]
         ifc_text = "\n".join([f"{l} /* Testcase */" if f"#{inst.id()}=" in l else l for l in lines])
         basename = f"{result}-" + re.sub("[^0-9a-zA-Z]", "_", name.lower())
 
         # Write IFC to disk
-        f.write(os.path.join(outdir, "testcases", self.facet, f"{basename}.ifc"))
+        ifc.write(os.path.join(outdir, "testcases", self.facet, f"{basename}.ifc"))
 
         # Create an IDS with the applicability selecting exactly
         # the entity type passed to us in `inst`.
@@ -112,8 +107,73 @@ class DocGenerator:
         self.facet = facet
 
 
-test_facet.run = DocGenerator()
+class IdsDocGenerator:
+    def __init__(self):
+        self.testcases = []
+
+    def __call__(self, name, ids, ifc, expected, applicable_entities=[], failed_entities=[]):
+        ids.validate(ifc)
+        all_applicable = set()
+        all_failures = set()
+        for spec in ids.specifications:
+            assert spec.status is expected
+            all_applicable.update(spec.applicable_entities)
+            for requirement in spec.requirements:
+                if requirement.status is False:
+                    all_failures.update(requirement.failed_entities)
+        assert set(all_applicable) == set(applicable_entities)
+        assert set(all_failures) == set(failed_entities)
+
+        result = "pass" if expected is True else "fail"
+
+        regenerate_guids(ifc)
+
+        l = validate.json_logger()
+        validate.validate(ifc, l)
+        for issue in l.statements:
+            raise Exception("About to emit invalid example data:", issue)
+
+        lines = ifc.wrapped_data.to_string().split("\n")[7:-3]
+        ifc_text = ""
+        for i, line in enumerate(lines):
+            step_id = int(line[1 : line.index("=")])
+            element = ifc.by_id(step_id)
+            newline = "" if i == 0 else "\n"
+            if element in applicable_entities:
+                pass_or_fail = "FAIL" if element in failed_entities else "PASS"
+                ifc_text += f"{newline}[{pass_or_fail}] {line}"
+            else:
+                ifc_text += f"{newline}       {line}"
+        basename = f"{result}-" + re.sub("[^0-9a-zA-Z]", "_", name.lower())
+
+        # Write IFC to disk
+        ifc.write(os.path.join(outdir, "testcases", "ids", f"{basename}.ifc"))
+
+        # Write IDS to disk
+        with open(os.path.join(outdir, "testcases", "ids", f"{basename}.ids"), "w", encoding="utf-8") as ids_file:
+            ids_file.write(ids.to_string())
+
+        reports = []
+        for spec in ids.specifications:
+            report = {"applicability": [], "requirements": [], "usage": spec.get_usage(), "status": spec.status}
+            for facet in spec.applicability:
+                report["applicability"].append(facet.to_string("applicability"))
+            for facet in spec.requirements:
+                report["requirements"].append(
+                    {"status": facet.status, "text": facet.to_string("requirement"), "usage": facet.get_usage()}
+                )
+            reports.append(report)
+
+        xml_text = "\n".join([l[4:] for l in ids.to_string().split("\n")[4:-1]]).replace("\t", "  ")
+
+        self.testcases.append(
+            {"name": name, "ids": xml_text, "ifc": ifc_text, "basename": basename, "result": result, "reports": reports}
+        )
+
+
+test_facet.run = FacetDocGenerator()
 test_facet.set_facet = test_facet.run.set_facet
+test_ids.run = IdsDocGenerator()
 
 pytest.main(["-p", "no:pytest-blender"])
 
@@ -142,6 +202,42 @@ for facet, testcases in test_facet.run.testcases.items():
             )
             write()
 
+with open(os.path.join(outdir, f"testcases-ids.md"), "w") as f:
+    write = functools.partial(print, file=f)
+    write(f"# IDS integration testcases")
+    write()
+    write(
+        "These testcases are designed to help describe behaviour in edge cases and ambiguities. All valid IDS implementations must demonstrate identical behaviour to these test cases."
+    )
+    write()
+    for testcase in test_ids.run.testcases:
+        write(f"## [{testcase['result'].upper()}] {testcase['name']}")
+        write()
+        write("~~~xml")
+        write(testcase["ids"])
+        write("~~~")
+        write()
+        write("~~~lua")
+        write(testcase["ifc"])
+        write("~~~")
+        write()
+        for report in testcase["reports"]:
+            write("```")
+            icon = "✔️" if report["status"] else "❌"
+            write(f"# {icon} Specification ({report['usage']})")
+            write("Applies to:")
+            for facet in report["applicability"]:
+                write(f" - {facet}")
+            write("Requirements:")
+            for facet in report["requirements"]:
+                icon = "✔️" if facet["status"] else "❌"
+                write(f" - {icon} {facet['text']} ({facet['usage']})")
+            write("```")
+            write()
+        write(
+            f"[Sample IDS](testcases/ids/{testcase['basename']}.ids) - [Sample IFC](testcases/ids/{testcase['basename']}.ifc)"
+        )
+        write()
 
 specs = ifctester.ids.Ids(
     title="buildingSMART Sample IDS",
@@ -153,15 +249,38 @@ specs = ifctester.ids.Ids(
     purpose="Contractual requirements",
 )
 
-spec = ifctester.ids.Specification(name="Project naming", ifcVersion=["IFC4"], description="Projects shall be named correctly for the purposes of identification, project archival, and model federation.", instructions="Each discipline is responsible for naming their own project.")
+spec = ifctester.ids.Specification(
+    name="Project naming",
+    ifcVersion=["IFC4"],
+    description="Projects shall be named correctly for the purposes of identification, project archival, and model federation.",
+    instructions="Each discipline is responsible for naming their own project.",
+)
 specs.specifications.append(spec)
 spec.applicability.append(ifctester.ids.Entity(name="IFCPROJECT"))
-spec.requirements.append(ifctester.ids.Attribute(name="Name", value="TEST", instructions="The project manager shall confirm the short project code with the client based on their real estate portfolio naming scheme."))
+spec.requirements.append(
+    ifctester.ids.Attribute(
+        name="Name",
+        value="TEST",
+        instructions="The project manager shall confirm the short project code with the client based on their real estate portfolio naming scheme.",
+    )
+)
 
-spec = ifctester.ids.Specification(name="Fire rating", ifcVersion=["IFC4"], description="All objects must have a fire rating for building compliance checks and to know the protection strategies needed for any penetrations.", instructions="The architect is responsible for including this data.")
+spec = ifctester.ids.Specification(
+    name="Fire rating",
+    ifcVersion=["IFC4"],
+    description="All objects must have a fire rating for building compliance checks and to know the protection strategies needed for any penetrations.",
+    instructions="The architect is responsible for including this data.",
+)
 specs.specifications.append(spec)
 spec.applicability.append(ifctester.ids.Entity(name="IFCWALLTYPE"))
 restriction = ifctester.ids.Restriction(options="(-|[0-9]{2,3})\/(-|[0-9]{2,3})\/(-|[0-9]{2,3})", type="pattern")
-spec.requirements.append(ifctester.ids.Property(propertySet="Pset_WallCommon", name="FireRating", value=restriction, instructions="Fire rating is specified using the Fire Resistance Level as defined in the Australian National Construction Code (NCC) 2019. Valid examples include -/-/-, -/120/120, and 60/60/60"))
+spec.requirements.append(
+    ifctester.ids.Property(
+        propertySet="Pset_WallCommon",
+        name="FireRating",
+        value=restriction,
+        instructions="Fire rating is specified using the Fire Resistance Level as defined in the Australian National Construction Code (NCC) 2019. Valid examples include -/-/-, -/120/120, and 60/60/60",
+    )
+)
 
 specs.to_xml(os.path.join(outdir, "library", "sample.ids"))
diff --git a/src/ifctester/test/test_facet.py b/src/ifctester/test/test_facet.py
index d8e23a32a1..2cae4dabc4 100644
--- a/src/ifctester/test/test_facet.py
+++ b/src/ifctester/test/test_facet.py
@@ -583,14 +583,14 @@ class TestAttribute:
         run(
             "Durations are treated as strings 1/2",
             facet=facet,
-            inst=ifc.createIfcClassification(Name="Name", EditionDate="PT16H"),
-            expected=False,
+            inst=ifc.createIfcTaskTime(Name="Name", ScheduleDuration="PT16H"),
+            expected=True,
         )
         ifc = ifcopenshell.file()
         run(
             "Durations are treated as strings 2/2",
             facet=facet,
-            inst=ifc.createIfcClassification(Name="Name", EditionDate="P2D"),
+            inst=ifc.createIfcTaskTime(Name="Name", ScheduleDuration="P2D"),
             expected=False,
         )
 
@@ -598,30 +598,27 @@ class TestAttribute:
         facet = Attribute(name=restriction)
         ifc = ifcopenshell.file()
         run(
-            "Name restrictions may be used 1/4",
+            "Name restrictions will match any result 1/3",
             facet=facet,
             inst=ifc.createIfcMaterialLayerSet(
                 MaterialLayers=[ifc.createIfcMaterialLayer(LayerThickness=1)], LayerSetName="Foo"
             ),
             expected=True,
         )
-        ifc = ifcopenshell.file()
-        run(
-            "Name restrictions may be used 2/4",
-            facet=facet,
-            inst=ifc.createIfcMaterialConstituentSet(Name="Foo"),
-            expected=True,
-        )
-
         restriction = Restriction(options=["Name", "Description"], type="enumeration")
         facet = Attribute(name=restriction)
         ifc = ifcopenshell.file()
-        run("Name restrictions may be used 3/4", facet=facet, inst=ifc.createIfcWall(Name="Foo"), expected=False)
+        run(
+            "Name restrictions will match any result 2/3",
+            facet=facet,
+            inst=ifc.createIfcWall(Name="Foo"),
+            expected=True,
+        )
         ifc = ifcopenshell.file()
         run(
-            "Name restrictions may be used 4/4",
+            "Name restrictions will match any result 3/3",
             facet=facet,
-            inst=ifc.createIfcWall(Name="Foo", Description="Bar"),
+            inst=ifc.createIfcWall(Description="Bar"),
             expected=True,
         )
 
@@ -639,6 +636,7 @@ class TestAttribute:
         wall_type = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWallType")
         ifcopenshell.api.run("type.assign_type", ifc, related_object=wall, relating_type=wall_type)
         wall_type.Description = "Foobar"
+        facet = Attribute(name="Description", value="Foobar")
         run("Attributes are not inherited by the occurrence", facet=facet, inst=wall, expected=False)
 
         restriction = Restriction(options=["42"], type="enumeration", base="string")
@@ -857,18 +855,7 @@ class TestProperty:
     def test_filtering_using_a_property_facet(self):
         set_facet("property")
 
-        ifc = ifcopenshell.file()
-        ifc.createIfcProject()
-        # Milli prefix used to check measurement conversions
-        lengthunit = ifcopenshell.api.run("unit.add_si_unit", ifc, unit_type="LENGTHUNIT", name="METRE", prefix="MILLI")
-        areaunit = ifcopenshell.api.run(
-            "unit.add_si_unit", ifc, unit_type="AREAUNIT", name="SQUARE_METRE", prefix="MILLI"
-        )
-        volumeunit = ifcopenshell.api.run(
-            "unit.add_si_unit", ifc, unit_type="VOLUMEUNIT", name="CUBIC_METRE", prefix="MILLI"
-        )
-        timeunit = ifcopenshell.api.run("unit.add_si_unit", ifc, unit_type="TIMEUNIT", name="SECOND")
-        ifcopenshell.api.run("unit.assign_unit", ifc, units=[lengthunit, areaunit, volumeunit, timeunit])
+        ifc = self.setup_ifc()
 
         facet = Property(propertySet="Foo_Bar", name="Foo", measure="IfcLabel")
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
@@ -876,11 +863,12 @@ class TestProperty:
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
         ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties={"AnotherProperty": "AnotherValue"})
         run("Elements with a matching pset but no property also fail", facet=facet, inst=element, expected=False)
-        ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties={"Foo": None})
+        ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties={"AnotherProperty": None})
         run("Properties with a null value fail", facet=facet, inst=element, expected=False)
         ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties={"Foo": "Bar"})
         run("A name check will match any property with any string value", facet=facet, inst=element, expected=True)
 
+        ifc = self.setup_ifc()
         facet = Property(propertySet="Foo_Bar", name="Foo", measure="IfcLabel")
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
@@ -912,6 +900,7 @@ class TestProperty:
             expected=True,
         )
 
+        ifc = self.setup_ifc()
         facet = Property(propertySet="Foo_Bar", name="Foo", value="Bar", measure="IfcLabel")
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
@@ -933,6 +922,7 @@ class TestProperty:
         ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties={"Foo": ifc.createIfcIdentifier(identifier)})
         run("IDS does not handle string truncation such as for identifiers", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         facet = Property(propertySet="Foo_Bar", name="Foo", value="1", measure="IfcLabel")
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
@@ -1009,6 +999,7 @@ class TestProperty:
         ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties={"Foo": ifc.createIfcDuration("P2D")})
         run("Durations are treated as strings 1/2", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Pset_WallCommon")
         pset_template = ifcopenshell.util.pset.get_template("IFC4").get_by_name("Pset_WallCommon")
@@ -1026,6 +1017,7 @@ class TestProperty:
         facet = Property(propertySet="Pset_WallCommon", name="Status", value="NEW", measure="IfcLabel")
         run("Any matching value in an enumerated property will pass 3/3", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
         list_property = ifc.createIfcPropertyListValue(
@@ -1039,6 +1031,7 @@ class TestProperty:
         facet = Property(propertySet="Foo_Bar", name="Foo", value="Z", measure="IfcLabel")
         run("Any matching value in a list property will pass 3/3", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
         bounded_property = ifc.createIfcPropertyBoundedValue(
@@ -1057,6 +1050,7 @@ class TestProperty:
         facet = Property(propertySet="Foo_Bar", name="Foo", value="2", measure="IfcLengthMeasure")
         run("Any matching value in a bounded property will pass 4/4", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
         table_property = ifc.createIfcPropertyTableValue(
@@ -1070,12 +1064,14 @@ class TestProperty:
         facet = Property(propertySet="Foo_Bar", name="Foo", value="Y", measure="IfcLabel")
         run("Any matching value in a table property will pass 3/3", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
         pset.HasProperties = [ifc.createIfcPropertyReferenceValue(Name="Foo")]
         facet = Property(propertySet="Foo_Bar", name="Foo", measure="IfcLabel")
         run("Reference properties are treated as objects and not supported", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcDoor")
         pset = ifc.create_entity(
             "IfcDoorPanelProperties",
@@ -1099,6 +1095,7 @@ class TestProperty:
         )
         run("Predefined properties are supported but discouraged 2/2", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         facet = Property(propertySet="Foo_Bar", name="Foo", measure="IfcLengthMeasure")
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         qto = ifcopenshell.api.run("pset.add_qto", ifc, product=element, name="Foo_Bar")
@@ -1107,6 +1104,7 @@ class TestProperty:
         facet = Property(propertySet="Foo_Bar", name="Foo", measure="IfcAreaMeasure")
         run("Quantities must also match the appropriate measure", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
         complex_property = ifc.createIfcComplexProperty(Name="Foo", UsageName="RabbitAgilityTraining")
@@ -1117,6 +1115,7 @@ class TestProperty:
         facet = Property(propertySet="Foo", name="Rabbits", measure="IfcLabel")
         run("Complex properties are not supported 2/2", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         qto = ifcopenshell.api.run("pset.add_qto", ifc, product=element, name="Foo_Bar")
         complex_quantity = ifc.createIfcPhysicalComplexQuantity(Name="Foo", Discrimination="FurThickness")
@@ -1129,6 +1128,7 @@ class TestProperty:
         facet = Property(propertySet="Foo", name="MyLength", measure="IfcLengthMeasure")
         run("Complex properties are not supported 2/2", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         restriction = Restriction(options="Foo_.*", type="pattern")
         facet = Property(propertySet=restriction, name="Foo", measure="IfcLabel")
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
@@ -1141,6 +1141,7 @@ class TestProperty:
         ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties={"Foo": "Bar"})
         run("All matching property sets must satisfy requirements 3/3", facet=facet, inst=element, expected=True)
 
+        ifc = self.setup_ifc()
         restriction = Restriction(options="Foo.*", type="pattern")
         facet = Property(propertySet="Foo_Bar", name=restriction, value="x", measure="IfcLabel")
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
@@ -1152,6 +1153,7 @@ class TestProperty:
         ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties={"Foobar": "x", "Foobaz": "y"})
         run("All matching properties must satisfy requirements 3/3", facet=facet, inst=element, expected=False)
 
+        ifc = self.setup_ifc()
         restriction1 = Restriction(options="Foo.*", type="pattern")
         restriction2 = Restriction(options=["x", "y"], type="enumeration")
         facet = Property(propertySet="Foo_Bar", name=restriction1, value=restriction2, measure="IfcLabel")
@@ -1172,6 +1174,7 @@ class TestProperty:
             expected=False,
         )
 
+        ifc = self.setup_ifc()
         facet = Property(propertySet="Foo_Bar", name="Foo", value="2", measure="IfcTimeMeasure")
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
@@ -1180,6 +1183,7 @@ class TestProperty:
         ifcopenshell.api.run("pset.edit_pset", ifc, pset=pset, properties={"Foo": ifc.createIfcTimeMeasure(2)})
         run("Measures are used to specify an IFC data type 2/2", facet=facet, inst=element, expected=True)
 
+        ifc = self.setup_ifc()
         facet = Property(propertySet="Foo_Bar", name="Foo", value="2", measure="IfcLengthMeasure")
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         pset = ifcopenshell.api.run("pset.add_pset", ifc, product=element, name="Foo_Bar")
@@ -1198,6 +1202,7 @@ class TestProperty:
             expected=True,
         )
 
+        ifc = self.setup_ifc()
         wall = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         wall_type = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWallType")
         ifcopenshell.api.run("type.assign_type", ifc, related_object=wall, relating_type=wall_type)
@@ -1207,6 +1212,7 @@ class TestProperty:
         run("Properties can be inherited from the type 1/2", facet=facet, inst=wall, expected=True)
         run("Properties can be inherited from the type 2/2", facet=facet, inst=wall_type, expected=True)
 
+        ifc = self.setup_ifc()
         wall = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         wall_type = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWallType")
         ifcopenshell.api.run("type.assign_type", ifc, related_object=wall, relating_type=wall_type)
@@ -1218,6 +1224,21 @@ class TestProperty:
         run("Properties can be overriden by an occurrence 1/2", facet=facet, inst=wall, expected=True)
         run("Properties can be overriden by an occurrence 2/2", facet=facet, inst=wall_type, expected=False)
 
+    def setup_ifc(self):
+        ifc = ifcopenshell.file()
+        ifc.createIfcProject()
+        # Milli prefix used to check measurement conversions
+        lengthunit = ifcopenshell.api.run("unit.add_si_unit", ifc, unit_type="LENGTHUNIT", name="METRE", prefix="MILLI")
+        areaunit = ifcopenshell.api.run(
+            "unit.add_si_unit", ifc, unit_type="AREAUNIT", name="SQUARE_METRE", prefix="MILLI"
+        )
+        volumeunit = ifcopenshell.api.run(
+            "unit.add_si_unit", ifc, unit_type="VOLUMEUNIT", name="CUBIC_METRE", prefix="MILLI"
+        )
+        timeunit = ifcopenshell.api.run("unit.add_si_unit", ifc, unit_type="TIMEUNIT", name="SECOND")
+        ifcopenshell.api.run("unit.assign_unit", ifc, units=[lengthunit, areaunit, volumeunit, timeunit])
+        return ifc
+
 
 class TestMaterial:
     def test_creating_a_material_facet(self):
@@ -1258,7 +1279,6 @@ class TestMaterial:
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         material = ifcopenshell.api.run("material.add_material", ifc)
         ifcopenshell.api.run("material.assign_material", ifc, product=element, material=material)
-        run("Material with no data will fail a value check", facet=facet, inst=element, expected=False)
         material.Name = "Foo"
         run("A material name may pass the value check", facet=facet, inst=element, expected=True)
         material.Name = "Bar"
@@ -1270,7 +1290,6 @@ class TestMaterial:
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcWall")
         material_set = ifcopenshell.api.run("material.add_material_set", ifc, set_type="IfcMaterialList")
         ifcopenshell.api.run("material.assign_material", ifc, product=element, material=material_set)
-        run("A material list with no data will fail a value check", facet=facet, inst=element, expected=False)
         material = ifcopenshell.api.run("material.add_material", ifc)
         ifcopenshell.api.run("material.add_list_item", ifc, material_list=material_set, material=material)
         material.Name = "Foo"
@@ -1418,6 +1437,7 @@ class TestPartOf:
         run("An optional facet always passes regardless of outcome 1/2", facet=facet, inst=element, expected=True)
         run("An optional facet always passes regardless of outcome 2/2", facet=facet, inst=subelement, expected=True)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcSlab")
         subelement = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcBeam")
         ifcopenshell.api.run("aggregate.assign_object", ifc, product=subelement, relating_object=element)
@@ -1426,6 +1446,7 @@ class TestPartOf:
         facet = PartOf(entity="IFCWALL", relation="IfcRelAggregates")
         run("An aggregate may specify the entity of the whole 2/2", facet=facet, inst=subelement, expected=False)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcElementAssembly")
         subelement = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcSlab")
         subsubelement = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcBeam")
@@ -1434,6 +1455,7 @@ class TestPartOf:
         facet = PartOf(entity="IFCELEMENTASSEMBLY", relation="IfcRelAggregates")
         run("An aggregate entity may pass any ancestral whole passes", facet=facet, inst=subsubelement, expected=True)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcElementAssembly")
         group = ifcopenshell.api.run("group.add_group", ifc)
         facet = PartOf(relation="IfcRelAssignsToGroup")
@@ -1441,6 +1463,7 @@ class TestPartOf:
         ifcopenshell.api.run("group.assign_group", ifc, products=[element], group=group)
         run("A grouped element passes a group relationship", facet=facet, inst=element, expected=True)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcElementAssembly")
         group = ifc.createIfcInventory()
         facet = PartOf(entity="IFCGROUP", relation="IfcRelAssignsToGroup")
@@ -1449,6 +1472,7 @@ class TestPartOf:
         facet = PartOf(entity="IFCINVENTORY", relation="IfcRelAssignsToGroup")
         run("A group entity must match exactly 2/2", facet=facet, inst=element, expected=True)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcElementAssembly")
         container = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcSpace")
         facet = PartOf(relation="IfcRelContainedInSpatialStructure")
@@ -1457,6 +1481,7 @@ class TestPartOf:
         run("Any contained element passes a containment relationship 2/2", facet=facet, inst=element, expected=True)
         run("The container itself always fails", facet=facet, inst=container, expected=False)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcElementAssembly")
         container = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcSpace")
         ifcopenshell.api.run("spatial.assign_container", ifc, product=element, relating_structure=container)
@@ -1465,6 +1490,7 @@ class TestPartOf:
         facet = PartOf(relation="IfcRelContainedInSpatialStructure", entity="IFCSPACE")
         run("The container entity must match exactly 2/2", facet=facet, inst=element, expected=True)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcSlab")
         subelement = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcBeam")
         ifcopenshell.api.run("aggregate.assign_object", ifc, product=subelement, relating_object=element)
@@ -1473,6 +1499,7 @@ class TestPartOf:
         facet = PartOf(relation="IfcRelContainedInSpatialStructure", entity="IFCSPACE")
         run("The container may be indirect", facet=facet, inst=subelement, expected=True)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcFurniture")
         subelement = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcDiscreteAccessory")
         ifcopenshell.api.run("nest.assign_object", ifc, related_object=subelement, relating_object=element)
@@ -1480,6 +1507,7 @@ class TestPartOf:
         run("Any nested part passes a nest relationship", facet=facet, inst=subelement, expected=True)
         run("Any nested whole fails a nest relationship", facet=facet, inst=element, expected=False)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcFurniture")
         subelement = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcDiscreteAccessory")
         ifcopenshell.api.run("nest.assign_object", ifc, related_object=subelement, relating_object=element)
@@ -1488,6 +1516,7 @@ class TestPartOf:
         facet = PartOf(relation="IfcRelNests", entity="IFCFURNITURE")
         run("The nest entity must match exactly 2/2", facet=facet, inst=subelement, expected=True)
 
+        ifc = ifcopenshell.file()
         element = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcFurniture")
         subelement = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcDiscreteAccessory")
         subsubelement = ifcopenshell.api.run("root.create_entity", ifc, ifc_class="IfcMechanicalFastener")
@@ -1516,3 +1545,47 @@ class TestRestriction:
         assert restriction == "AB01"
         assert restriction != "AB"
         assert restriction != "01"
+
+    def test_filtering_using_an_enumeration(self):
+        set_facet("restriction")
+
+        ifc = ifcopenshell.file()
+        restriction = Restriction(options=["Foo", "Bar"], type="enumeration")
+        facet = Attribute(name="Name", value=restriction)
+        element = ifc.createIfcWall(Name="Foo")
+        run("An enumeration matches case sensitively 1/3", facet=facet, inst=element, expected=True)
+        element.Name = "Bar"
+        run("An enumeration matches case sensitively 1/3", facet=facet, inst=element, expected=True)
+        element.Name = "Baz"
+        run("An enumeration matches case sensitively 1/3", facet=facet, inst=element, expected=False)
+
+        ifc = ifcopenshell.file()
+        restriction = Restriction(options={"minInclusive": 0, "maxInclusive": 10}, type="bounds", base="integer")
+        element = ifc.createIfcSurfaceStyleRefraction(RefractionIndex=0)
+        facet = Attribute(name="RefractionIndex", value=restriction)
+        run("A bound can be inclusive 1/4", facet=facet, inst=element, expected=True)
+        element.RefractionIndex = 5
+        run("A bound can be inclusive 2/4", facet=facet, inst=element, expected=True)
+        element.RefractionIndex = 10
+        run("A bound can be inclusive 3/4", facet=facet, inst=element, expected=True)
+        element.RefractionIndex = 100
+        run("A bound can be inclusive 4/4", facet=facet, inst=element, expected=False)
+
+        restriction = Restriction(options={"minExclusive": 0, "maxExclusive": 10}, type="bounds", base="integer")
+        facet = Attribute(name="RefractionIndex", value=restriction)
+        element.RefractionIndex = 0
+        run("A bound can be inclusive 1/3", facet=facet, inst=element, expected=False)
+        element.RefractionIndex = 5
+        run("A bound can be inclusive 2/3", facet=facet, inst=element, expected=True)
+        element.RefractionIndex = 10
+        run("A bound can be inclusive 3/3", facet=facet, inst=element, expected=False)
+
+        ifc = ifcopenshell.file()
+        restriction = Restriction(options="[A-Z]{2}[0-9]{2}", type="pattern")
+        facet = Attribute(name="Name", value=restriction)
+        element = ifc.createIfcWall(Name="WT01")
+        run("Regex patterns can be used 1/3", facet=facet, inst=element, expected=True)
+        element.Name = "XY99"
+        run("Regex patterns can be used 2/3", facet=facet, inst=element, expected=True)
+        element.Name = "A5"
+        run("Regex patterns can be used 3/3", facet=facet, inst=element, expected=False)
diff --git a/src/ifctester/test/test_ids.py b/src/ifctester/test/test_ids.py
index 04c8f3ccdc..310090315f 100644
--- a/src/ifctester/test/test_ids.py
+++ b/src/ifctester/test/test_ids.py
@@ -23,6 +23,14 @@ import ifcopenshell
 from ifctester import ids
 
 
+def run(name, specs, model, expected, applicable_entities, failed_entities):
+    specs.validate(model)
+    spec = specs.specifications[0]
+    assert spec.status is expected
+    assert set(spec.applicable_entities) == set(applicable_entities)
+    assert set(spec.requirements[0].failed_entities) == set(failed_entities)
+
+
 class TestIds:
     def test_failing_on_opening_invalid_ids_data(self):
         with pytest.raises(xmlschema.validators.exceptions.XMLSchemaValidationError):
@@ -106,11 +114,73 @@ class TestIds:
         model = ifcopenshell.file()
         wall = model.createIfcWall()
         waldo = model.createIfcWall(Name="Waldo")
-        specs.validate(model)
+        run("A minimal IDS can check a minimal IFC 1/2", specs, model, False, [wall, waldo], [wall])
+        wall.Name = "Waldo"
+        run("A minimal IDS can check a minimal IFC 2/2", specs, model, True, [wall, waldo], [])
 
-        assert spec.status == False
-        assert set(spec.applicable_entities) == {wall, waldo}
-        assert spec.requirements[0].failed_entities == [wall]
+        spec.ifcVersion = []
+        run(
+            "Specification version is purely metadata and does not impact pass or fail result",
+            specs,
+            model,
+            True,
+            [wall, waldo],
+        )
+
+        spec.minOccurs = 1
+        model = ifcopenshell.file()
+        waldo = model.createIfcWall(Name="Waldo")
+        run("Required specifications need at least one applicable entity 1/2", specs, model, True, [waldo])
+        model = ifcopenshell.file()
+        waldo = model.createIfcSlab(Name="Waldo")
+        run("Required specifications need at least one applicable entity 2/2", specs, model, False)
+
+        spec.minOccurs = 0
+        model = ifcopenshell.file()
+        waldo = model.createIfcSlab(Name="Waldo")
+        run("Optional specifications may still pass if nothing is applicable", specs, model, True)
+
+        spec.minOccurs = 0
+        spec.maxOccurs = 0
+        model = ifcopenshell.file()
+        wall = model.createIfcSlab(Name="Waldo")
+        run("Prohibited specifications fail if at least one entity passes all requirements 1/3", specs, model, True)
+        model = ifcopenshell.file()
+        wall = model.createIfcWall(Name="Wally")
+        run("Prohibited specifications fail if at least one entity passes all requirements 2/3", specs, model, True, [wall], [wall])
+        model = ifcopenshell.file()
+        wall = model.createIfcWall(Name="Waldo")
+        run("Prohibited specifications fail if at least one entity passes all requirements 3/3", specs, model, False, [wall])
+
+        spec.minOccurs = 0
+        spec.maxOccurs = "unbounded"
+        model = ifcopenshell.file()
+        wall = model.createIfcWall(Name="Waldo")
+        spec.requirements.append(ids.Attribute(name="Description", value="Foobar"))
+        run("A specification passes only if all requirements pass 1/2", specs, model, False, [wall], [wall])
+        wall.Description = "Foobar"
+        run("A specification passes only if all requirements pass 2/2", specs, model, True, [wall])
+
+        spec.requirements[1].minOccurs = 0
+        wall.Description = None
+        run("Specification optionality and facet optionality can be combined", specs, model, True, [wall])
+
+        spec.minOccurs = 0
+        spec.maxOccurs = 0
+        spec.requirements[0].minOccurs = 0
+        spec.requirements[0].maxOccurs = 0
+        spec.requirements[1].minOccurs = 0
+        spec.requirements[1].maxOccurs = 0
+        wall.Name = "Waldo"
+        wall.Description = "Foobar"
+        run("A prohibited specification and a prohibited facet results in a double negative", specs, model, True, [wall])
+
+        spec = ids.Specification(name="Name")
+        spec.applicability.append(ids.Entity(name="IFCWALL"))
+        spec.requirements.append(ids.Attribute(name="Name", value="Waldo"))
+        specs.specifications.append(spec)
+        wall2 = model.createIfcWall(Name="Waldo")
+        run("Multiple specifications are independent of one another", specs, model, True, [wall, wall2])
 
     def test_creating_multiple_specifications(self):
         specs = ids.Ids(title="Title")
@@ -138,9 +208,12 @@ class TestIds:
 class TestSpecification:
     def test_create_specification_with_minimal_information(self):
         spec = ids.Specification()
+        print(spec.asdict())
         assert spec.asdict() == {
             "@name": "Unnamed",
             "@ifcVersion": ["IFC2X3", "IFC4"],
+            "@minOccurs": 0,
+            "@maxOccurs": "unbounded",
             "applicability": {},
             "requirements": {},
         }
@@ -148,8 +221,8 @@ class TestSpecification:
     def test_create_specification_with_all_possible_information(self):
         spec = ids.Specification(
             name="name",
-            minOccurs="0",
-            maxOccurs="unbounded",
+            minOccurs=1,
+            maxOccurs=1,
             ifcVersion="IFC4",
             identifier="identifier",
             description="description",
@@ -157,8 +230,8 @@ class TestSpecification:
         )
         assert spec.asdict() == {
             "@name": "name",
-            "@minOccurs": "0",
-            "@maxOccurs": "unbounded",
+            "@minOccurs": 1,
+            "@maxOccurs": 1,
             "@ifcVersion": "IFC4",
             "@identifier": "identifier",
             "@description": "description",