Defect classification (severity, priority) in Testing Fundamentals - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is defect severity in software testing?

Defect severity measures how serious a defect is in the software. It shows the impact of the defect on the system's functionality or performance.

beginner

What does defect priority indicate?

Defect priority tells how soon a defect should be fixed. It is based on business needs and urgency, not just technical impact.

intermediate

How do severity and priority differ?

Severity is about the defect's impact on the system. Priority is about how quickly the defect should be fixed. A defect can have high severity but low priority, or vice versa.

intermediate

Give an example of a defect with high severity but low priority.

An example is a defect that crashes a rarely used feature. It is serious (high severity) but can be fixed later (low priority) because it affects few users.

beginner

What are common levels used for defect severity?

Common severity levels are: Critical (system crash), Major (major function broken), Minor (small issue), Trivial (cosmetic issue).

Which term describes how quickly a defect should be fixed?

A Severity

B Priority

C Impact

D Risk

Priority indicates the urgency to fix a defect.

A defect that causes the system to crash is usually classified as:

A Low severity

B High priority

C Critical severity

D Trivial priority

System crashes are critical severity defects.

If a defect affects a minor cosmetic issue, what is its likely severity?

A Trivial

B Major

C Minor

D Critical

Cosmetic issues are usually trivial severity.

Which of the following can have high severity but low priority?

A A defect in a rarely used feature

B A defect causing system crash

C A typo on the homepage

D A defect blocking all users

Rarely used feature defects can be serious but fixed later.

Priority is usually decided by:

A Developers only

B Testers only

C Severity alone

D Business needs and urgency

Priority depends on business needs and urgency.

Explain the difference between defect severity and defect priority with examples.

Think about impact vs urgency.

List and describe common levels of defect severity.

Focus on how serious the defect is.

Practice

1.

What does severity indicate in defect classification?

easy

A. How serious or harmful the defect is

B. How soon the defect should be fixed

C. Who reported the defect

D. The number of times the defect occurred

Solution

1. Step 1: Understand the meaning of severity

   Severity measures the impact or seriousness of a defect on the system or user.

2. Step 2: Differentiate severity from priority

   Priority is about scheduling the fix, not the defect's impact.

3. Final Answer:

   How serious or harmful the defect is -> Option A

4. Quick Check:

   Severity = seriousness [OK]

Hint: Severity = impact level, not fix timing [OK]

Common Mistakes:

• Confusing severity with priority
• Thinking severity means who found the bug
• Assuming severity counts defect occurrences

2.

Which of the following is the correct way to classify a defect with high severity and low priority?

easy

A. A defect that is not serious and can be ignored

B. A defect that causes major system failure but can be fixed later

C. A minor UI glitch that must be fixed immediately

D. A defect that is serious and must be fixed immediately

Solution

1. Step 1: Understand high severity

   High severity means the defect causes major problems or failures.

2. Step 2: Understand low priority

   Low priority means the defect fix can be delayed or scheduled later.

3. Final Answer:

   A defect that causes major system failure but can be fixed later -> Option B

4. Quick Check:

   High severity + low priority = serious but delayed fix [OK]

Hint: High severity ≠ immediate fix if priority is low [OK]

Common Mistakes:

• Assuming high severity always means high priority
• Mixing up severity and priority meanings
• Ignoring the priority when severity is high

3.

Consider this defect list with severity and priority:
defects = [{'id':1, 'severity':'High', 'priority':'Low'}, {'id':2, 'severity':'Low', 'priority':'High'}, {'id':3, 'severity':'Medium', 'priority':'Medium'}]
Which defect should be fixed first based on priority?

medium

A. Defect with id 2

B. Defect with id 1

C. Defect with id 3

D. All defects have same priority

Solution

1. Step 1: Check priority values of each defect

   Defect 1 has priority Low, Defect 2 has priority High, Defect 3 has priority Medium.

2. Step 2: Determine which priority is highest

   High priority means fix first, so Defect 2 should be fixed first.

3. Final Answer:

   Defect with id 2 -> Option A

4. Quick Check:

   Highest priority = fix first [OK]

Hint: Fix defects with highest priority first [OK]

Common Mistakes:

• Choosing based on severity instead of priority
• Assuming Medium priority is higher than High
• Ignoring priority values

4.

Find the error in this defect classification code snippet:

def classify_defect(severity, priority):
    if severity == 'High' and priority == 'High'
        return 'Fix Immediately'
    else:
        return 'Schedule Fix'

medium

A. Function missing return statement

B. Wrong comparison operator used

C. Missing colon after if condition

D. Indentation error in else block

Solution

1. Step 1: Check syntax of if statement

   The if statement lacks a colon at the end of the condition line.

2. Step 2: Verify other parts of the function

   Return statements and else block indentation are correct.

3. Final Answer:

   Missing colon after if condition -> Option C

4. Quick Check:

   if condition must end with ':' [OK]

Hint: Check colons after if/else statements [OK]

Common Mistakes:

• Forgetting colon after if condition
• Misplacing indentation in else block
• Assuming missing return statement

5.

You have a list of defects with severity and priority:
defects = [{'id':101, 'severity':'Medium', 'priority':'High'}, {'id':102, 'severity':'High', 'priority':'Low'}, {'id':103, 'severity':'Low', 'priority':'Medium'}]
Write a Python expression using dictionary comprehension to create a dictionary mapping defect id to 'Fix Immediately' if priority is High, else 'Fix Later'.

hard

A. {d['id']: ('Fix Immediately' if d['priority'] == 'High') else 'Fix Later' for d in defects}

B. {d['id']: 'Fix Immediately' if d['priority'] == 'High' for d in defects}

C. {d['id']: 'Fix Immediately' if d['priority'] = 'High' else 'Fix Later' for d in defects}

D. {d['id']: ('Fix Immediately' if d['priority'] == 'High' else 'Fix Later') for d in defects}

Solution

1. Step 1: Understand dictionary comprehension syntax

   It uses {key: value for item in iterable} with conditional expressions inside value.

2. Step 2: Check conditional expression correctness

   {d['id']: ('Fix Immediately' if d['priority'] == 'High' else 'Fix Later') for d in defects} correctly uses parentheses and '==' for comparison inside the expression.

3. Final Answer:

   {d['id']: ('Fix Immediately' if d['priority'] == 'High' else 'Fix Later') for d in defects} -> Option D

4. Quick Check:

   Correct dict comprehension with conditional [OK]

Hint: Use parentheses around if-else in dict comprehension [OK]

Common Mistakes:

• Using single '=' instead of '==' in condition
• Missing parentheses around conditional expression
• Placing else outside parentheses