From 4886cef85a3ba8155d5bb35e9d899c1e7b19aceb Mon Sep 17 00:00:00 2001
From: Jukka Aho <ahojukka5@gmail.com>
Date: Mon, 15 Dec 2025 10:25:57 +0200
Subject: [PATCH] test(mesh): add mesh coloring test

New 20-line test file for mesh coloring:
- Tests that create_coloring produces valid graph coloring
- Validates that elements in same color don't share nodes
- Uses Abaqus mesh file (cube_tet4.inp) for testing

Essential for parallel element assembly where elements sharing
nodes must be processed in different colors to avoid race conditions.
---
 test/mesh/test_coloring.jl | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 test/mesh/test_coloring.jl

diff --git a/test/mesh/test_coloring.jl b/test/mesh/test_coloring.jl
new file mode 100644
index 0000000..5e43966
--- /dev/null
+++ b/test/mesh/test_coloring.jl
@@ -0,0 +1,20 @@
+using JuliaFEM, LinearAlgebra, Test
+
+datadir = first(splitext(basename(@__FILE__)))
+
+@testset "Test that mesh coloring provides a good coloring"
+    fn = joinpath(datadir, "cube_tet4.inp")
+    mesh = JuliaFEM.Mesh(open(parse_abaqus, fn))
+
+    coloring = JuliaFEM.create_coloring(mesh)
+    for colors in coloring
+        for ele_i in colors
+            for ele_j in colors
+                if ele_i == ele_j
+                    continue
+                end
+                @test intersect(Set(mesh.elements[ele_i]), Set(mesh.elements[ele_j])) |> isempty
+            end
+        end
+    end
+end
\ No newline at end of file