test(dofs): add runtests.jl

Test suite organizer for DOF system module.
Includes field unification and DOF system tests.

test/dofs/runtests.jl

@@ -0,0 +1,23 @@
+# This file is a part of JuliaFEM.
+# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE
+
+"""
+DOF System Test Suite
+
+Runs all tests for the DOF (Degree of Freedom) system.
+
+Usage:
+    julia --project=. test/dofs/runtests.jl
+"""
+
+using Test
+using JuliaFEM
+using Tensors
+
+# All DOF types and functions are in flat JuliaFEM namespace
+
+@testset "DOF System Tests" begin
+    @testset "Field Type Unification" begin
+        include("test_field_unification.jl")
+    end
+end