Test-Driven Development

Question 1

What is testing?

Answer 1

Executing a program with the intention of finding errors in the code

Question 2

What are the stages of the Waterfall model? (6)

Answer 2

• Analysis
• Specification
• Design
• Implementation
• Testing
• Operation & Maintenance

Question 3

What are the problems of the Waterfall model? (4)

Answer 3

• Testing happens late, if at all
• Requirements decoupled from code during development
• Quality is someone else’s problem (SEP)
• Hard work to test, so not all problems are identified

Question 4

What is Test-Driven Development (TDD)? (3)

Answer 4

• Identify a feature to be implemented and write an initially failing automated test case for it
• Write code to pass the test
• Run the test again and previous tests if any and repeat

Question 5

What is TDD a good approach to development? (2)

Answer 5

• Making small improvements frequently ensures having a working system at all times
• System is less volatile to modifications when they are small and incremental

Question 6

What does the concept of YAGNI mean?

Answer 6

Don’t build stuff because it might be useful, and keep code as simple as it can be

Question 7

What elements should a unit test have? (4)

Answer 7

• Focused, testing one thing at a time
• Fast to run
• Independent of each other, run order and the environment
• Automatic

Question 8

What is the coverage of unit tests? (3)

Answer 8

• Every method tested
• Every statement tested
• Every branch tested

Question 9

What are the test cases for a method that sorts an array of integers? (7)

Answer 9

• Array is null
• Array has zero length
• Array has one length
• All elements are the same
• Some elements are null
• Array is already sorted
• Array is reverse sorted

Question 10

What is the control flow for unit testing? (4)

Answer 10

• New instance of test class created for every test
• Create objects needed for the test
• Establish state for start of the test
• Tidy up if necessary

Question 11

What is the control flow for a unit test in terms of Java annotations? (5)

Answer 11

@BeforeClass
@Before
@Test
@After
@AfterClass