diagnostic vs testing

diagnostic

noun
  • Any technique used in medical diagnosis. 

  • That by which anything is known; a symptom. 

  • Any tool or technique used to find the root of a problem. 

adj
  • Characteristic of a particular disease. 

  • Serving to indicate or specify a particular item or thing within a group of similar things. 

  • Of, or relating to diagnosis. 

  • Intended to assess a student's preexisting knowledge on the material being taught. 

testing

noun
  • The act of conducting a test; trialing, proving. 

adj
  • Difficult; tough. 

How often have the words diagnostic and testing occurred in a corpus of books? (source: Google Ngram Viewer )