Module 5: Delta Debugging

Question 1

why simplify test cases?

Answer 1

1. ease of communication
2. easier debugging: smaller test cases result in smaller states and shorter executions
3. identify duplicates: simplified test cases subsume several duplicates

Question 2

how do we minimize test cases?

Answer 2

binary search

• cut the test case in half
• iterate

Question 3

binary search process

Answer 3

this is a naive way to minimize input and not always a good solution

Question 4

line granularity

Answer 4

only partition the input at line breaks

Question 5

minimizing test cases

Answer 5

exponential

bad!

Question 6

one minimality

Answer 6

different problem formulation:

find a set of changes that cause the failure, but removing any change causes the failure to go away

Question 7

1 minimality

Answer 7

Question 8

delta debugging

Answer 8

a technique, not a tool
bad news: probably must be re-implemented for each significant system to exploit knowledge changes
good news: relatively simple algorithm, big payoff; it is worth re-implementing