Ticket 231

A teacher, Maya, sends a message to the helpdesk.

"I open the marks page for my new class. It shows an error. I have a lesson in ten minutes!"

You are on the support team today. What do you do first? Do you guess? Do you change something and hope? A good team follows a process.

Key words

Word	What it means	Example
Ticket	A record of one user problem, with its number and its history.	Ticket 231
Helpdesk	The people who answer users' questions and problems.	The support team
Replicate	Make the problem happen again, on purpose, to see it yourself.	Open a class with no marks
Root cause	The real reason for the problem.	The code divides by zero. You cannot divide by 0
User error	The user did something the system does not expect. Often the design was unclear.	Typing a space in a number
System error	A fault in the machines or the way they connect, not in the code.	The server ran out of memory
Application error	A bug in the software itself.	A crash on an empty list
Security breach	Somebody got in, or got data they must not have.	Stolen passwords
Stakeholder	A person who cares about the product or is affected by it.	The teacher who reported the problem
Lessons learned	A short written note on what went wrong and how to prevent it.	Test empty lists

The cells students fill in are left blank in this preview.

Step 1: see it yourself

First, make the problem happen again. This is called replicating it.

Ask the user: What did you press? What did you expect? What happened? Then do the same yourself. If you can make it happen, you can fix it. If you cannot, ask for more detail.

Try it: replicate the problem

Code: python

def average_mark(marks):
    return sum(marks) / len(marks)

print(average_mark([50, 70]))   # a class with marks: works

# Now try a class with no marks. Remove the # on the next line and run.
# print(average_mark([]))

# You can see the error. That is the problem in ticket 231.

Suspect a security breach?

data-callouts.warning.label

Stop. Tell the security lead at once. Do not delete anything. Logs (records of what happened) are evidence. Do not guess in public. Follow your company plan.

Step 2: fix it and test it

When the cause is a bug, follow four steps:

Write a test that shows the error. It fails now.
Change the code until the test passes. The error is gone.
Keep the test. If the error comes back, the test fails and tells you.
Run all the old tests. Nothing else may break.