Higher Computing Science: Software Testing

1. SOFTWARE TESTING
Higher Computing Science

2. COMPREHENSIVE TEST PLAN
Why do we test?
• To identify errors or bugs in code
• To ensure that the program is fit for purpose (matches the specification)
• To show that all of the functional requirements set out in the
specification are met
• To ensure that the code runs efficiently

3. TEST DATA
• Normal – falls within the acceptable limits of the program
• Extreme – on the limits of acceptable data
• Exceptional – should not be accepted by the program (and the user
should be given some feedback)

4. TEST DATA
Example: A program should ask the user to enter test scores for a class of
students. The test was out of 50. Produce a suitable test table.
Test Table
Normal data 47 89
Extreme data 0 100
Exceptional data 340 $abc

5. SYNTAX ERRORS
• Mis-spelled keywords
• Incorrect use of programming language rules

6. EXECUTION ERRORS
• Cause the program to crash
• These are sometimes called run-time errors

7. EXECUTION ERRORS
• Cause the program to crash
• These are sometimes called run-time errors

8. LOGIC ERRORS
• Program will not crash but it will produce unexpected results

9. DRY RUN
• Programmer works through each line of code on paper (or on screen)
following the program logic

10. TRACE TABLE
• Programmer works through each line of code on paper (or on screen)
following the program logic.
• Example – find minimum

11. TRACE TABLE
line num_array minimum counter
1 [7, 4, 2, 6]
2 7
4 1
6 4
4 2
6 2
4 3
6 2

12. BREAKPOINT
• A breakpoint can be set to stop the program when that line of code is
executed.
• This allows the programmer to inspect the values held in variables.

13. WATCHPOINT
• A watchpoint is a breakpoint which is mapped to a variable.
• The program will stop running when the value in that variable changes.