"To test the waters" means to cautiously explore or try something, usually to gather information or gauge the reaction before committing fully. Full definition
A relatively low - risk strategy for testing the waters of overseas working could be to spend some time in another lab during your PhD. (sciencemag.org)
Whether you want to just test the waters in supporting our organization or jump in with both feet, there are opportunities to fit your goals, schedule, and abilities. (bcrofmn.org)
To ensure consistency of quality in your grapes and wine, the study recommends testing the water before and after harvest and the soil at least every 3 years. (grapeconnect.com)