Concurrency Lecture 5

Question 1

What is a mutation operator?

Answer 1

A bug that we inject into our concurrency code to find help find faults in our code.

Question 2

Name the steps in the Quality Assurance Process.

Answer 2

1. Get system source code that is to be tested.
2. Do a static analysis of the code.
3. Create a set of test targets.
4. Write the tests according to the targets.
5. Execute the test.sets.
6. Perform a test set evaluation of the results.

Question 3

What are the advantages of using mutation operators?

Answer 3

• They give us better insight into the code we are testing

- Help decide whether or not the coverage metric we are using is suitable

Question 4

Why can only writing tests for our code not be as good as also using mutation operators?

Answer 4

• Sometimes tests cannot reveal all concurrency faults and bugs.
• It can be hard to write tests for every single test target we found

Question 5

What do we do once we have added mutation operators to our code?

Answer 5

We run the mutated code with the tests that we wrote. Then we observe what new bugs have been revealed by our mutations. We then calculate the mutation score.

Question 6

How do we calculate mutation score?

Answer 6

(Number of bugs revealed)
_______________________________ x 100
(Total number of bugs)

Question 7

What are bug patterns?

Answer 7

Bugs that arise in faulty code. They are common mistakes that a programmer makes.

Question 8

What does the mutation operator: Modify Method Timeout do?

Answer 8

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Question 9

What does the mutation operator: Modify Synchronized Block Parameter do?

Answer 9

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Question 10

What does the mutation operator: Exchange Synchronized Block Parameters do?

Answer 10

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Question 11

What does the mutation operator: Remove Thread Method Call do?

Answer 11

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Question 12

What does the mutation operator: Remove Concurrency Mechanism Method Call do?

Answer 12

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Question 13

What does the mutation operator: Replace notifyAll() With notify() do?

Answer 13

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Question 14

What does the mutation operator: Replace join() With sleep() do?

Answer 14

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Question 15

What does the mutation operator: Remove Synchronized Keyword From Method do?

Answer 15

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Question 16

What does the mutation operator: Remove Synchronized Method do?

Answer 16

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Question 17

What does the mutation operator: Remove Finally Around Unlock do?

Answer 17

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Question 18

What does the mutation operator: Replace One Concurrency Mechanism With Another do?

Answer 18

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Question 19

What does the mutation operator: Exchange Explicit Block Object do?

Answer 19

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Question 20

What does the mutation operator: Shift Critical Region do?

Answer 20

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Question 21

What does the mutation operator: Expand Critical Region do?

Answer 21

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Question 22

What does the mutation operator: Shrink Critical Region do?

Answer 22

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Question 23

What does the mutation operator: Split Critical Region do?

Answer 23

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