Hi,
Just try to enter non-ASCII character into the field and see what happens.
Several notes regarding 'functionality that "user can enter only ASCII characters in a text
filed."' requirement :
-- Do you have a definition of non-ASCII character? Is Unicode, UTF-16 or something else assumed? (This because, for example, Carriage Return symbol has ASCII code 13d (0x0D). Likewise what about, for example ASCII(255) ? )
-- According to the provided requirement, you should check whether or not it is possible just to enter the character. Nothing is said about what is expected in both cases.
Your actual test code might be different depending on the answers to the above questions.
