Change unit test to ignore deprecation Warning on using *.txt extension with RF 3.1.
Change unit test to ignore deprecation Warning on using *.txt extension with RF 3.1.

robotframework/RIDE,HelioGuilherme66/RIDE,HelioGuilherme66/RIDE,robotframework/RIDE,robotframework/RIDE,HelioGuilherme66/RIDE,HelioGuilherme66/RIDE,robotframework/RIDE