Selecting & Using Suitable Test Data (OCR GCSE Computer Science)

Normal, Boundary & Erroneous Tests

Categories of tests

• There are three main categories of tests a programmer or test-user would carry out whilst performing both iterative or final testing on a program

  • Normal tests

  • Boundary tests

  • Erroneous tests

• There is an additional test that users would always carry out to test the robustness of their program, this is known as an invalid test

• To explain the types of tests, some example code will be used

Example code

# Ask for user's name
name = input("What is your name? ")

# Ask for user's age
age = int(input("How old are you? "))

# Check if age is between 12 and 18
if age >= 12 and age <= 18:
    print("Welcome, " + name + "! Your age is accepted.")
else:
    print("Sorry, " + name + ". Your age is not accepted.")

Normal tests

• A normal test is when a user enters data that should be accepted in the program

• An example would be a user entering their age as 16 into the age field of the program

Boundary tests

• A boundary test is when a user enters data that is on the edge of what is acceptable 

• An example would be a user entering their age as 12 or 18 into the age field of the program

Erroneous tests

• An erroneous test is when a user enters data that is the wrong data type

• An example would be a user entering their age as "F" into the age field of the program

Invalid tests

• An invalid test is when a user enters data that is the right data type but it is outside of what is accepted

• An example would be a user entering their age as 67 into the age field of the program

Selecting suitable test data