From 34b3c385b4a69874b73b0ffbda94b9246d49d94c Mon Sep 17 00:00:00 2001
From: Jukka Aho <ahojukka5@gmail.com>
Date: Sat, 9 May 2026 18:38:14 +0300
Subject: [PATCH] test(dofs): add Tet4 facet map tests

---
 test/dofs/test_tet4_facet_maps.jl | 92 +++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 test/dofs/test_tet4_facet_maps.jl

diff --git a/test/dofs/test_tet4_facet_maps.jl b/test/dofs/test_tet4_facet_maps.jl
new file mode 100644
index 0000000..59d58d3
--- /dev/null
+++ b/test/dofs/test_tet4_facet_maps.jl
@@ -0,0 +1,92 @@
+# This file is a part of JuliaFEM.
+# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
+
+using Test
+using JuliaFEM
+using JuliaFEM: Tet4FacetMaps, build_tet4_facet_maps, tet4_edge_orientation_sign
+using JuliaFEM: FacetMassKernel, EdgeMassKernel
+using JuliaFEM: DOFBasedCOOAssembler, DOFBasedCOOCache, assemble!, extract_system
+using LinearAlgebra
+
+@testset "build_tet4_facet_maps (single tet)" begin
+    nodes = Vec{3, Float64}[
+        Vec(0.0, 0.0, 0.0),
+        Vec(1.0, 0.0, 0.0),
+        Vec(0.0, 1.0, 0.0),
+        Vec(0.0, 0.0, 1.0),
+    ]
+    conn = (UInt32(1), UInt32(2), UInt32(3), UInt32(4))
+    mesh = Mesh{Tet4}(nodes, [conn])
+    maps = build_tet4_facet_maps(mesh)
+    @test maps isa Tet4FacetMaps
+    @test maps.n_edges == 6
+    @test maps.n_faces == 4
+    @test size(maps.elem_face_orientation) == (4, 1)
+    @test all(o -> abs(o) == 1, maps.elem_face_orientation)
+
+    for le in 1:6
+        @test tet4_edge_orientation_sign(conn, le) == maps.elem_edge_orientation[le, 1]
+    end
+
+    S = @DOFSet{e::DOF{Float64, Edge}}
+    elements, handler = create_elements!(mesh, Element{Tet4, Lagrange{1}, S})
+    @test handler.total_dofs == 6
+end
+
+@testset "two Tet4 sharing one triangular face" begin
+    nodes = Vec{3, Float64}[
+        Vec(0.0, 0.0, 0.0),
+        Vec(1.0, 0.0, 0.0),
+        Vec(0.0, 1.0, 0.0),
+        Vec(0.0, 0.0, 1.0),
+        Vec(0.0, 0.0, -1.0),
+    ]
+    c1 = (UInt32(1), UInt32(2), UInt32(3), UInt32(4))
+    c2 = (UInt32(1), UInt32(2), UInt32(3), UInt32(5))
+    mesh = Mesh{Tet4}(nodes, [c1, c2])
+    maps = build_tet4_facet_maps(mesh)
+    @test maps.n_faces == 7
+    @test maps.n_edges == 9
+
+    products = Int[]
+    for le1 in 1:6, le2 in 1:6
+        if maps.elem_edge_gid[le1, 1] == maps.elem_edge_gid[le2, 2]
+            push!(products, Int(maps.elem_edge_orientation[le1, 1] * maps.elem_edge_orientation[le2, 2]))
+        end
+    end
+    @test !isempty(products)
+    @test all(abs(p) == 1 for p in products)
+    # Same nodal edge-direction convention as Hex8 — shared edges can match (+1,+1).
+    @test any(==(1), products)
+end
+
+@testset "FacetMassKernel / EdgeMassKernel on reference Tet4" begin
+    nodes = Vec{3, Float64}[
+        Vec(0.0, 0.0, 0.0),
+        Vec(1.0, 0.0, 0.0),
+        Vec(0.0, 1.0, 0.0),
+        Vec(0.0, 0.0, 1.0),
+    ]
+    conn = (UInt32(1), UInt32(2), UInt32(3), UInt32(4))
+    mesh = Mesh{Tet4}(nodes, [conn])
+
+    Sf = @DOFSet{flux::DOF{Float64, Face}}
+    ef, hf = create_elements!(mesh, Element{Tet4, Lagrange{1}, Sf})
+    kf = FacetMassKernel(mesh)
+    cf = DOFBasedCOOCache(ef, hf, mesh, kf)
+    assemble!(cf, DOFBasedCOOAssembler(), kf, mesh)
+    Kf, _ = extract_system(cf)
+    d = diag(Matrix(Kf))
+    expected_faces = 1.5 + sqrt(3) / 2  # three right triangles + equilateral √2-side face
+    @test sum(d) ≈ expected_faces rtol = 1e-10
+
+    Se = @DOFSet{circ::DOF{Float64, Edge}}
+    ee, he = create_elements!(mesh, Element{Tet4, Lagrange{1}, Se})
+    ke = EdgeMassKernel(mesh)
+    ce = DOFBasedCOOCache(ee, he, mesh, ke)
+    assemble!(ce, DOFBasedCOOAssembler(), ke, mesh)
+    Ke, _ = extract_system(ce)
+    de = diag(Matrix(Ke))
+    expected_edges = 3.0 + 3 * sqrt(2.0)
+    @test sum(de) ≈ expected_edges rtol = 1e-10
+end