The test fixture includes a housing, a first grip, and a second grip. The first grip and the second grip are each configured to clamp onto an upper surface and lower surface of a material coupon. The test fixture also includes an upper input jaw and a lower input jaw each configured to clamp onto the material coupon near a center of the upper surface and the lower surface of the material coupon. The test fixture is configured to load the material coupon in a first direction and a second direction. The first grip and the second grip are each configured to clamp onto the material coupon at a location which accordingly results in a desired testing ratio regardless of a variation in thickness of the material coupon.