There are many tests that can be done on materials to determine their properties or qualities. The tests can be either destructive or non-destructive.
Destructive tests are often conducted to determine a specific property of the material/component being tested. They usually require a specifically shaped test piece to be made and this is damaged/destroyed during testing.
Examples of destructive tests are tensile tests, impact tests, and fatigue tests. Hardness tests are also done on test pieces (destructive). Additionally, hardness tests are often done on actual components (non-destructive).