Fix #6960. String reporting of cardinality did not match upstream docs.

The meaning of the upstream docs changed subtly a year ago and I never
caught up. There is still work to do.

src/ifctester/ifctester/facet.py

@@ -126,14 +126,16 @@ class Facet:
     ) -> str:
         if clause_type == "applicability":
             templates = self.applicability_templates
-        elif clause_type == "requirement":
-            is_prohibited = False
             if specification and specification.maxOccurs == 0:
-                is_prohibited = not is_prohibited
-            if requirement and requirement.cardinality == "prohibited":
-                is_prohibited = not is_prohibited
-            templates = self.prohibited_templates if is_prohibited else self.requirement_templates
-            if requirement and requirement.cardinality == "optional":
+                templates = self.prohibited_templates
+        elif clause_type == "requirement":
+            if specification and specification.maxOccurs == 0:
+                return "The requirement is not applicable"
+            if (not requirement) or isinstance(requirement, Entity) or requirement.cardinality == "required":
+                templates = self.requirement_templates
+            elif requirement.cardinality == "prohibited":
+                templates = self.prohibited_templates
+            elif requirement.cardinality == "optional":
                 templates = [
                     t.replace("shall", "may").replace("Shall", "May").replace("must", "may") for t in templates
                 ]

src/ifctester/test/test_facet.py

@@ -32,6 +32,7 @@ import ifcopenshell.api.type
 import ifcopenshell.api.unit
 import ifcopenshell.guid
 import ifcopenshell.util.pset
+import ifctester.ids
 import ifctester.facet
 from ifctester.facet import Entity, Attribute, Classification, Property, PartOf, Material, Restriction
 
@@ -229,6 +230,31 @@ class TestEntity:
         wall3 = ifcopenshell.api.root.create_entity(ifc, ifc_class="IfcWall", predefined_type="BAZFOO")
         run("Restrictions an be specified for the predefined type 3/3", facet=facet, inst=wall3, expected=False)
 
+    def test_to_string_required_applicability(self):
+        spec = ifctester.ids.Specification(name="Foo", minOccurs=1, maxOccurs="unbounded")
+        facet = Entity(name="IFCWALL")
+        assert facet.to_string("applicability", spec) == "All IFCWALL data"
+
+    def test_to_string_optional_applicability(self):
+        spec = ifctester.ids.Specification(name="Foo", minOccurs=0, maxOccurs="unbounded")
+        facet = Entity(name="IFCWALL")
+        assert facet.to_string("applicability", spec) == "All IFCWALL data"
+
+    def test_to_string_prohibited_applicability(self):
+        spec = ifctester.ids.Specification(name="Foo", minOccurs=0, maxOccurs=0)
+        facet = Entity(name="IFCWALL")
+        assert facet.to_string("applicability", spec) == "Shall not be IFCWALL data"
+
+    def test_to_string_ignored_requirement(self):
+        spec = ifctester.ids.Specification(name="Foo", minOccurs=0, maxOccurs=0)
+        facet = Entity(name="IFCWALL")
+        assert facet.to_string("requirement", spec) == "The requirement is not applicable"
+
+    def test_to_string_required_requirement(self):
+        spec = ifctester.ids.Specification(name="Foo")
+        facet = Entity(name="IFCWALL")
+        assert facet.to_string("requirement", spec) == "Shall be IFCWALL data"
+
 
 class TestAttribute:
     def test_creating_an_attribute_facet(self):