The word “test” originally referred to “a small vessel used in assaying precious metals.” This meant that testing was a method of ascertaining the quality of gold or silver. It was also used in the process of refining valuable alloys, such as tin.
Later, the term was adopted in other fields, and these days it’s common to find it in contexts such as education, medicine, or software development. Its essence, however, has not changed: testing is used to refine end value.