Cost of bugs at different stages in Testing Fundamentals - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Cost impact of fixing bugs in different stages

Which stage typically incurs the highest cost to fix a software bug?

A During the requirements gathering phase

B During the design phase

C After the software has been released to customers

D During the coding phase

💡 Hint

Think about how much effort it takes to fix a bug after users start using the software.

Bugs found after release are the most expensive to fix because they may require patches, customer support, and can damage reputation.

🧠 Conceptual

intermediate

Relative cost of fixing bugs in testing vs coding

Compared to fixing bugs during coding, fixing bugs found during testing is usually:

A More expensive because the bug has been integrated into more code

B Less expensive because testing is automated

C The same cost because both happen before release

D Impossible to estimate

💡 Hint

Consider how many parts of the software might be affected by the time testing happens.

Bugs found during testing often require more effort to fix because they may affect multiple modules and require regression testing.

❓ Predict Output

advanced

Cost multiplier calculation for bug fixes

What is the output of the following Python code that calculates cost multipliers for fixing bugs at different stages?

Testing Fundamentals

stages = ['Requirements', 'Design', 'Coding', 'Testing', 'Production']
cost_multipliers = [1, 5, 10, 20, 100]

for stage, cost in zip(stages, cost_multipliers):
    print(f"{stage}: ${cost * 100}")

A

Requirements: $100
Design: $500
Coding: $1000
Testing: $2000
Production: $10000

B

Requirements: $1
Design: $5
Coding: $10
Testing: $20
Production: $100

C

Requirements: $100
Design: $500
Coding: $1000
Testing: $2000
Production: $10000
Extra: $0

D SyntaxError due to missing colon in for loop

💡 Hint

Check the multiplication of cost multipliers by 100 and the print format.

The code multiplies each cost multiplier by 100 and prints the stage with the calculated cost.

❓ assertion

advanced

Assertion to verify bug cost increase

Which assertion correctly verifies that the cost to fix a bug in production is at least 10 times the cost in coding?

Testing Fundamentals

cost_coding = 1000
cost_production = 12000

A assert cost_production < cost_coding

B assert cost_coding >= 10 * cost_production

C assert cost_production == cost_coding * 5

D assert cost_production >= 10 * cost_coding

💡 Hint

Think about which cost should be larger and by what factor.

The assertion checks that production cost is at least 10 times coding cost, which matches the data.

🔧 Debug

expert

Identify the error in cost calculation code

What error does the following code raise when calculating bug fix costs?

Testing Fundamentals

costs = {'requirements': 1, 'design': 5, 'coding': 10, 'testing': 20, 'production': 100}

for stage in ['requirements', 'design', 'coding', 'testing', 'deployment']:
    print(f"{stage}: ${costs[stage] * 100}")

A TypeError because costs values are integers

B KeyError because 'deployment' is not in the costs dictionary

C SyntaxError due to missing colon in for loop

D No error, prints all costs correctly

💡 Hint

Check if all stages in the list exist as keys in the dictionary.

The key 'deployment' is not defined in the costs dictionary, causing a KeyError.