In youtube a video is playing how do you pause the playing video ,with out touching the mobile tell me scenarios -----------HOW DO U DO COMPATIBILITY TESTING ,IF THE COMPANY TELLS TO DO TEST A FEATURE LIKE " IRIS " SCANNER BUT COMPANY CANNOT AFFORD ALL TYPES OF COMPANIES MOBILES (INTERVIEWR TELLS TO CHOOSE 2 LATEST MODEL MOBILES OF DIFFERENT COMPANIES) AND ASKS US THAT IT SHOULD WORK FOR ALL COMPANY MOBILES HOW DO U TEST?