When you run a series of tests on something, it's called a trial. If you invent a computer game and want to run it through a trial before releasing it, you might hire a bunch of teenagers to play it.
A trial is also a court hearing to legally determine the result of a particular case. If your cousin is arrested for stealing her neighbor's dog, she may be put on trial. This term can also be used more generically, especially to talk about something being tried in the court of public opinion. The fate of music education is on trial in many school districts facing budget cuts.