Added a test to RefinementRulesTests.jl that fails and should not

Author: amartinhuertas

test/AdaptivityTests/RefinementRulesTests.jl

@@ -22,6 +22,9 @@ for poly in polys
   rr_red = Adaptivity.RedRefinementRule(poly)
   Adaptivity.test_refinement_rule(rr_red)
 
+  rrules=[rr_generic, rr_white, rr_red]
+  @test isconcretetype(eltype(rrules))
+
   n_edges = num_faces(poly,1)
   for e in 1:n_edges
     rr_green = Adaptivity.GreenRefinementRule(poly,e)