test(basis): add basis metadata description tests

test/basis/test_basis_description.jl

@@ -0,0 +1,47 @@
+# SPDX-FileCopyrightText: 2015-2026 Jukka Aho
+# SPDX-License-Identifier: MIT
+
+using Test
+using JuliaFEM
+using Tensors
+
+struct _CoverageDummyBasis <: AbstractBasis end
+
+@testset "Basis description API" begin
+    desc = JuliaFEM.VandermondeBasisDescription(
+        name="unit-test",
+        description="coverage",
+        topology=Triangle{3},
+        family=Lagrange{1},
+        ansatz=(),
+    )
+    @test JuliaFEM.basis_family(desc) === Lagrange{1}
+    @test JuliaFEM.basis_topology(desc) === Triangle{3}
+    @test JuliaFEM.basis_order(desc) === 1
+
+    desc_s = JuliaFEM.VandermondeBasisDescription(
+        name="ser",
+        description="coverage",
+        topology=Quadrilateral{4},
+        family=Serendipity{2},
+        ansatz=(),
+    )
+    @test JuliaFEM.basis_order(desc_s) === 2
+
+    desc_bad = JuliaFEM.VandermondeBasisDescription(
+        name="bad",
+        description="coverage",
+        topology=Triangle{3},
+        family=_CoverageDummyBasis,
+        ansatz=(),
+    )
+    @test_throws ErrorException JuliaFEM.basis_order(desc_bad)
+
+    xi = Vec{2}((0.2, 0.25))
+    tri = Triangle{3}()
+    lag = Lagrange{1}()
+    vals = get_basis_functions(tri, lag, xi)
+    dvals = get_basis_derivatives(tri, lag, xi)
+    @test get_basis_function(tri, lag, xi, 1) == vals[1]
+    @test get_basis_derivative(tri, lag, xi, 2) == dvals[2]
+end