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

Categories of tests

• The 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

Type of Test	Input	Expected Output
Normal	14	Accepted
Normal	16	Accepted
Boundary	12	Accepted
Boundary	19	Rejected
Erroneous	H	Rejected
Erroneous	@	Rejected
Invalid	36	Rejected
Invalid	2	Rejected