Emma is writing a program to encrypt text entered by a user. Only letters, spaces and punctuation marks can be encrypted. Each letter in the text is replaced by the letter three places further down the alphabet. A is replaced by D, b by e, … Y by B, z by c. Spaces and punctuation marks are not changed.
Complete the test plan below by stating, for each input data and expected outcome, the type of test and a reason for the test.