Complete the semantic reconciliation roadmap

internal/modules/dnd/normalize/locationregistry/normalizer_test.go

@@ -44,6 +44,16 @@ func TestModuleContractAndMetadata(t *testing.T) {
 	}
 }
 
+func TestNormalizeRejectsNilSourceDocument(t *testing.T) {
+	_, err := newNormalizer(t, &recordingLocationNormalizerClient{}).Normalize(
+		context.Background(),
+		contracts.TypedNormalizeRequest[dnd.LocationRegistry]{},
+	)
+	if err == nil || !strings.Contains(err.Error(), "source document must not be nil") {
+		t.Fatalf("Normalize() error = %v, want nil source rejection", err)
+	}
+}
+
 func TestNormalizePreparesOnlyExactDuplicatesAndRetainsSameNameAndNestedPlaces(t *testing.T) {
 	input := dnd.LocationRegistry{Locations: []dnd.Location{
 		{Name: "  The Tavern  ", SourceRefs: []source.SourceRef{{SourceID: "session", StartUnitID: 1, EndUnitID: 1}}},