"test ground" is a correct and usable phrase in written English.
It can be used to refer to a place or situation where experiments or trials are conducted to test the effectiveness or feasibility of something. Example: Our laboratory is the perfect test ground for new inventions and technologies.
I could probably have gone to a job at a Test ground but what difference could I really make?
Kaliningrad and Poland looked like the likely test ground for visa-free travel between Russia and some of the EU".
It picked Rwanda out of dozens of countries as a test ground for bringing electronic payments to "frontier economies".
He says he plans to keep trying, and his current work is a kind of test ground of his commitment.
Italian scooter manufacturer Piaggio has successfully operated a fully integrated hydrogen fuel cell scooter at its test ground in Pontedera.
In this test ground, the boreholes revealed that the weathered granite alternately changes between moderate and strong.
In this way, E3 could become an interesting test ground for two competing visions regarding the future of immersive interactive entertainment.
Site investigations to test ground conditions are ongoing across the Olympic Park and the latest investigations took place at Clays Lane.
"Just as the world came together in the fight against HIV/Aids, we need to free up regulation so that we can test ground-breaking new drugs, and examine whether the period for market exclusivity could be extended.
It serves also as a test-ground and illustration of the benefits and drawbacks of discrete and continuum viewpoints.
Attitudes toward adoption are friendly, it's a test-ground for new technologies and services, and the culture and environment is not representative of any other culture.
