test(validation): add unit tests for validation module

Author: amaurigmartins

test/unit_Validation/test_rules_tubular.jl

@@ -0,0 +1,26 @@
+@testitem "Validation(Tubular): rule order unit test" setup = [defaults] begin
+    # Use fully-qualified names; do not add extra `using` here.
+    V = LineCableModels.Validation
+    T = LineCableModels.DataModel.Tubular
+    M = LineCableModels.Materials.Material
+
+    r = V._rules(T)
+
+    expected = (
+        V.Normalized(:radius_in), V.Normalized(:radius_ext),
+        V.Finite(:radius_in), V.Nonneg(:radius_in),
+        V.Finite(:radius_ext), V.Nonneg(:radius_ext),
+        V.Less(:radius_in, :radius_ext),
+        V.Finite(:temperature),
+        V.IsA{M}(:material_props),
+    )
+
+    if r != expected
+        @error "[Validation] Rule set for Tubular is wrong. Someone ‘helpfully’ changed the bundle order or duplicated rules.\n" *
+               "Expected exact structural equality with the generated bundle. Fix your traits/extra_rules and stop being clever."
+        @show expected
+        @show r
+    end
+
+    @test r == expected
+end