Usually used with someone you are flirting with via txt or FB to:
1. Gage the extent to which you can flirt with them
2. Most importantly, provide a get put clause allowing you to Deny all knowledge of said flirtation by calling it 'a reaction test' in case things balls up
All of the above allows the tester to safely vet all conversation and then pass or fail testee. Also see 'shit test'

When you eat dirt for the first time and leave your family to build a shack in the woods