chore(test): drop elasticity helper validation suite

Remove unused helper verification tests.

- Delete `test/validation/test_elasticity_helpers.jl`.

test/validation/test_elasticity_helpers.jl

@@ -1,213 +0,0 @@
-# This file is a part of JuliaFEM.
-# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
-
-"""
-Standalone test for elasticity assembly helpers.
-
-Tests core helper functions WITHOUT requiring Element/BasisInfo infrastructure.
-Uses Tensors.jl types directly.
-"""
-
-using Test
-using LinearAlgebra
-using Tensors
-
-# Include material models
-include("../benchmarks/material_models_benchmark.jl")
-
-# Define standalone helper functions (simplified from assembly_helpers.jl)
-
-"""Compute strain from shape function gradients and displacement."""
-function compute_strain_from_gradients(
-    ∇N::NTuple{N,Vec{3,Float64}},
-    u::AbstractVector{Float64}
-) where N
-    @assert length(u) == 3N "Displacement vector size mismatch"
-
-    # Displacement gradient: F = ∂u/∂X = ∑ᵢ uᵢ ⊗ ∇Nᵢ
-    # Small strain: ε = ½(F + Fᵀ)
-
-    F = zero(Tensor{2,3,Float64})
-    for i in 1:N
-        u_node = Vec{3}((u[3i-2], u[3i-1], u[3i]))
-        F += u_node ⊗ ∇N[i]
-    end
-
-    # Symmetrize to get small strain tensor
-    ε = symmetric(F)
-
-    return ε
-end
-
-"""Accumulate element stiffness matrix."""
-function accumulate_stiffness!(
-    K_e::Matrix{Float64},
-    ∇N::NTuple{N,Vec{3,Float64}},
-    𝔻::SymmetricTensor{4,3,Float64},
-    weight::Float64
-) where N
-
-    @inbounds for i in 1:N
-        for j in 1:N
-            # Stiffness contribution: Kᵢⱼ = ∫ ∇Nᵢ : 𝔻 : ∇Nⱼ dV
-            # Split into spatial dimensions for explicit loops
-            for α in 1:3  # Component of node i
-                for β in 1:3  # Component of node j
-                    # Sum over spatial indices (compiler unrolls)
-                    val = 0.0
-                    @simd for k in 1:3
-                        @simd for l in 1:3
-                            val += ∇N[i][k] * 𝔻[k, α, l, β] * ∇N[j][l]
-                        end
-                    end
-                    K_e[3(i-1)+α, 3(j-1)+β] += weight * val
-                end
-            end
-        end
-    end
-
-    return nothing
-end
-
-@testset "Elasticity Assembly Helpers (Standalone)" begin
-
-    @testset "Material Model Integration" begin
-        E = 200e9  # Pa
-        ν = 0.3
-        material = LinearElastic(E=E, ν=ν)
-
-        # Test uniaxial strain
-        ε = SymmetricTensor{2,3}((0.001, 0.0, 0.0, 0.0, 0.0, 0.0))
-        σ, 𝔻, _ = compute_stress(material, ε, NoState(), 0.1)
-
-        λ = E * ν / ((1 + ν) * (1 - 2ν))
-        μ = E / (2(1 + ν))
-
-        @test σ[1, 1] ≈ (λ + 2μ) * 0.001 atol = 1e-3
-        @test σ[2, 2] ≈ λ * 0.001 atol = 1e-3
-        @test σ[3, 3] ≈ λ * 0.001 atol = 1e-3
-
-        println("✅ Material model correct")
-    end
-
-    @testset "Strain Computation" begin
-        # Simple test: uniform extension in x-direction
-        # ∇N gradients chosen so that: ε_xx = 0.001, all others = 0
-
-        ∇N = (
-            Vec{3}((1.0, 0.0, 0.0)),  # Node 1
-            Vec{3}((0.0, 0.0, 0.0)),  # Node 2
-            Vec{3}((0.0, 0.0, 0.0)),  # Node 3
-            Vec{3}((0.0, 0.0, 0.0))   # Node 4
-        )
-
-        # Displacement: u₁ = [0.001, 0, 0], others zero
-        u = zeros(12)
-        u[1] = 0.001
-
-        ε = compute_strain_from_gradients(∇N, u)
-
-        @test ε[1, 1] ≈ 0.001 atol = 1e-6
-        @test ε[2, 2] ≈ 0.0 atol = 1e-6
-        @test ε[3, 3] ≈ 0.0 atol = 1e-6
-        @test ε[1, 2] ≈ 0.0 atol = 1e-6
-
-        println("✅ Strain computation correct")
-    end
-
-    @testset "Zero Allocation" begin
-        # Setup
-        ∇N = ntuple(4) do i
-            Vec{3}((randn(), randn(), randn())) / 10.0
-        end
-        u = randn(12) .* 0.01
-
-        E = 200e9
-        ν = 0.3
-        λ = E * ν / ((1 + ν) * (1 - 2ν))
-        μ = E / (2(1 + ν))
-        I = one(SymmetricTensor{2,3,Float64})
-        𝕀ˢʸᵐ = one(SymmetricTensor{4,3,Float64})
-        𝔻 = λ * I ⊗ I + 2μ * 𝕀ˢʸᵐ
-
-        # Test compute_strain_from_gradients
-        alloc1 = @allocated compute_strain_from_gradients(∇N, u)
-        @test alloc1 == 0
-
-        # Test accumulate_stiffness!
-        K_e = zeros(12, 12)
-        alloc2 = @allocated accumulate_stiffness!(K_e, ∇N, 𝔻, 1.0)
-        @test alloc2 == 0
-
-        println("✅ Zero allocations confirmed")
-    end
-
-    @testset "Type Stability" begin
-        ∇N = ntuple(4) do i
-            Vec{3}((0.1, 0.1, 0.1))
-        end
-        u = zeros(12)
-
-        # Should infer to SymmetricTensor{2,3,Float64,6}
-        @inferred compute_strain_from_gradients(∇N, u)
-
-        E = 200e9
-        ν = 0.3
-        λ = E * ν / ((1 + ν) * (1 - 2ν))
-        μ = E / (2(1 + ν))
-        I = one(SymmetricTensor{2,3,Float64})
-        𝕀ˢʸᵐ = one(SymmetricTensor{4,3,Float64})
-        𝔻 = λ * I ⊗ I + 2μ * 𝕀ˢʸᵐ
-        K_e = zeros(12, 12)
-
-        # Should infer to Nothing
-        @inferred accumulate_stiffness!(K_e, ∇N, 𝔻, 1.0)
-
-        println("✅ Type stability confirmed")
-    end
-
-    @testset "Stiffness Matrix Properties" begin
-        # Create realistic gradients
-        ∇N = (
-            Vec{3}((-0.5, -0.5, -0.5)),
-            Vec{3}((0.5, 0.0, 0.0)),
-            Vec{3}((0.0, 0.5, 0.0)),
-            Vec{3}((0.0, 0.0, 0.5))
-        )
-
-        E = 200e9
-        ν = 0.3
-        λ = E * ν / ((1 + ν) * (1 - 2ν))
-        μ = E / (2(1 + ν))
-        I = one(SymmetricTensor{2,3,Float64})
-        𝕀ˢʸᵐ = one(SymmetricTensor{4,3,Float64})
-        𝔻 = λ * I ⊗ I + 2μ * 𝕀ˢʸᵐ
-
-        K_e = zeros(12, 12)
-        accumulate_stiffness!(K_e, ∇N, 𝔻, 1.0)
-
-        # Check symmetry
-        @test K_e ≈ K_e' atol = 1e-10
-
-        # Check positive definiteness (approximately - some modes are zero)
-        eigs = eigvals(K_e)
-        # In a proper element, first 6 eigenvalues are ~0 (rigid body modes)
-        # Others should be positive
-        positive_eigs = count(λ -> λ > 1e6, eigs)
-        @test positive_eigs >= 3  # At least some positive modes
-
-        println("✅ Stiffness matrix properties validated")
-    end
-
-end
-
-println("\n" * "="^60)
-println("STANDALONE HELPERS TEST SUMMARY")
-println("="^60)
-println("✅ Material model integration working")
-println("✅ Strain computation correct")
-println("✅ Zero allocations confirmed")
-println("✅ Type stability verified")
-println("✅ Stiffness matrix properties validated")
-println("="^60)
-println("\n🎉 Core helper functions ready for full assembly!")