testing ground 
noun
An area or field of activity used for the testing of a product or an idea, especially a military site used for the testing of weapons: a nuclear testing ground his novel is used as a testing ground for these concepts...
- The audio stories may not enjoy the same mainstream success as TV Who, but they provide a fertile testing ground for new ideas and talent.
- The Civil War became the testing ground for widespread use of anesthesia during surgery.
- FarmLinks will be the ideal testing ground for PTI's new line of coated pesticide products.