Worksheet

F6.3 Testing and test data

Robust programs · GCSE · OCR J277 2.3.2, AQA 8525 3.2.11, Edexcel 1CP2 6.1.6 · about 15 min

What this lesson is about

Iterative and final testing; normal, boundary, invalid and erroneous data; test plans in code.

• When to test
• Choosing test data
• A test plan
• Tests the program runs itself
• Testing a robot

Questions 5 marks in all

1. [1 mark]A speed must be from 0 to 100. Which is boundary test data?

   1. A100
   2. B55
   3. Cfast
   4. D250

2. [1 mark]A speed must be from 0 to 100. Which is erroneous test data?

   1. Afast
   2. B100
   3. C55
   4. D0

3. [1 mark]What is iterative testing?

   1. ATesting each part as it is built, and fixing it before moving on
   2. BTesting once the whole program is finished
   3. CTesting with random data
   4. DTesting by a different person

4. [1 mark]When should the expected result in a test plan be worked out?

   1. ABefore running the test, from the requirements
   2. BAfter seeing what the program does
   3. COnly if the test fails
   4. DIt is not needed

5. [1 mark]What does this program print?

   def valid(s):
       return 0 < s < 100
   
   print(valid(0), valid(50), valid(100))

The task: fix it with tests

The test program below has a boundary bug. Fix valid_speed so every test prints pass, without changing the tests. Then add two more tests of your own: one normal, one erroneous. All tests must pass.

# the two lines every program starts with: the commands, then the robot
from bugbot import *
connect()

def valid_speed(text):
    """True if text is a whole number from 0 to 100."""
    return text.isdigit() and 0 < int(text) < 100

tests = [("50", True), ("0", True), ("100", True), ("101", False), ("-5", False), ("fast", False)]

for number, (data, expected) in enumerate(tests, start=1):
    actual = valid_speed(data)
    result = "pass" if actual == expected else "FAIL"
    print(f"test {number}: {data!r} expected {expected}, got {actual}: {result}")

Plan your program here, then type it in and press Run.

Do it on the robot
www.bugbotlab.com/learn/f6-3-testing-and-test-data/
The simulator checks it and tells you when it passes. Nothing to install, no account.

Challenges

1. Write a test plan for the validated drive from lesson F6.1, with at least two tests of each kind of data.
2. Write valid_code(text) for six-character class codes, and a list of tests for it, before you write the function.
3. Is " 50", with a space, normal or erroneous data for valid_speed? Decide what it should do, add a test, and make it pass.