Validates core assembly implementation by solving single Tet10 element
under uniaxial tension and comparing to analytical solution.
Test coverage:
- Linear elastic material model validation
- Strain computation from gradients (uniaxial extension)
- Assembly helpers zero allocation verification
- Type stability verification
- Stiffness matrix properties (symmetry, positive definiteness)
- Internal forces accumulation
Validates complete assembly infrastructure works correctly.
Jukka Aho