Which test assesses a material's ability to absorb energy before breaking?

The toughness test is the correct choice because it specifically measures a material's ability to absorb energy and deform plastically before fracturing. Toughness represents the amount of energy a material can absorb during deformation and is an important property for materials that will undergo sudden or impact loads.

This test typically results in a toughness value that is expressed in terms of energy absorbed per unit volume, often reported in joules per cubic meter (J/m³). Materials showing high toughness can withstand a greater amount of stress and strain without failing, making them vital for applications where impact resistance is critical.

In contrast, the tensile test measures the behavior of a material under tension, focusing primarily on the material's strength and ductility rather than its energy absorption capability. The hardness test assesses resistance to deformation, specifically surface indentation, while the compression test evaluates a material's ability to withstand axial loads. Both the hardness and compression tests do not directly measure energy absorption before fracture like the toughness test does.