test: unit tests fixed for new subkinds

Author: mpusz

test/static/hep_test.cpp

@@ -131,19 +131,26 @@ static_assert(verify(hep::phase, real_scalar, one));  // phase is dimensionless
 
 // Test quantity hierarchy conversions
 // All specialized lengths can be implicitly converted up the hierarchy to generic length
-static_assert(implicitly_convertible(hep::radiation_length, hep::length));
 static_assert(implicitly_convertible(hep::decay_length, hep::length));
-static_assert(implicitly_convertible(hep::interaction_length, hep::length));
 static_assert(implicitly_convertible(hep::nuclear_interaction_length, hep::interaction_length));
 
+// is_kind quantities form subkinds
+static_assert(!implicitly_convertible(hep::radiation_length, hep::length));
+static_assert(explicitly_convertible(hep::radiation_length, hep::length));
+static_assert(!implicitly_convertible(hep::interaction_length, hep::length));
+static_assert(explicitly_convertible(hep::interaction_length, hep::length));
+
+static_assert(!implicitly_convertible(hep::proper_time, hep::duration));
+static_assert(explicitly_convertible(hep::proper_time, hep::duration));
+static_assert(!implicitly_convertible(hep::coordinate_time, hep::duration));
+static_assert(explicitly_convertible(hep::coordinate_time, hep::duration));
+
 // But cannot be implicitly converted between each other (different physical concepts!)
 static_assert(!implicitly_convertible(hep::radiation_length, hep::decay_length));
 static_assert(!implicitly_convertible(hep::decay_length, hep::interaction_length));
 static_assert(!implicitly_convertible(hep::impact_parameter, hep::vertex_position));
 
 // Specialized times: proper_time vs coordinate_time are distinct
-static_assert(implicitly_convertible(hep::proper_time, hep::duration));
-static_assert(implicitly_convertible(hep::coordinate_time, hep::duration));
 static_assert(!implicitly_convertible(hep::proper_time, hep::coordinate_time));
 static_assert(!implicitly_convertible(hep::coordinate_time, hep::proper_time));