diff --git a/test/static/quantity_spec_test.cpp b/test/static/quantity_spec_test.cpp
index b845e4c8..862ac0c9 100644
--- a/test/static/quantity_spec_test.cpp
+++ b/test/static/quantity_spec_test.cpp
@@ -198,6 +198,8 @@ static_assert(is_of_type<pow<2>(length) / pow<2>(length), dimensionless_>);
 static_assert(is_of_type<pow<2>(length) / length, length_>);
 static_assert(is_of_type<length / pow<2>(length), derived_quantity_spec<dimensionless_, per<length_>>>);
 
+static_assert(is_of_type<length / height, derived_quantity_spec<length_, per<height_>>>);
+
 static_assert(is_of_type<length * time, derived_quantity_spec<length_, time_>>);
 static_assert(is_of_type<length * length, derived_quantity_spec<mp_units::power<length_, 2>>>);
 
@@ -625,6 +627,10 @@ static_assert(convertible_impl(power / power, efficiency) == explicit_conversion
 static_assert(convertible_impl(stress / stress, strain) == explicit_conversion);
 static_assert(convertible_impl(stress / stress, efficiency) == explicit_conversion);
 
+// specialized dimensionless to dimensionless and back
+static_assert(convertible_impl(height / width, dimensionless) == yes);
+static_assert(convertible_impl(dimensionless, height / width) == explicit_conversion);
+
 // derived with dimensionless remainder after explosion
 // TODO revise that
 static_assert(convertible_impl(distance / speed, time) == yes);