stake out vs test the waters

stake out

verb
  • To watch a location and/or people, generally covertly. 

  • To mark off the limits by stakes 

  • To end the game by hitting the stake peg in the middle of the court. 

test the waters

verb
  • To explore or probe, as before making a commitment. 

How often have the words stake out and test the waters occurred in a corpus of books? (source: Google Ngram Viewer )