Annette Allen - The what, why and how of Unit Testing with SQL Server Slides from the TechExeter Conference, 8th October 2016. www.techexeter.uk

1. The What, Why and How of Unit Testing
Annette Allen

2. Who is Annette Allen
 DBA/Dev for 14 years
 Joint Chapter Leader of SQL South West based in the South
West of England
 Event organiser
 Friend of Red Gate
 UK Regional Mentor

3. Agenda
 Why do we test?
 What we test?
 How do we test?

4. Why

5. Why get requirements?
Requirements
Acceptance Criteria
Test List

6. How do we get requirements?
 Conversation
 Email
 Backlog

7. I want . . . . .

9. Speak to stakeholder
 I want. . . . .
 A car that is cheap, young and practical

12. Requirements
 I want:
 “A list of cars that are cheap, young and practical”

13. Requirements
 “I need a car that is under 5 years old, costs less than £10k can
do more than 40mpg and can take 4 people”.

14. Tests
 1. Price is under £10k
 2. Age is under 5
 3. Seats >= 4
 4. Fuel economy > 40 mpg

15. Acceptance Criteria
 The car must be under 5 years old
 The car must cost less than £10k
 The car must have at least 4 seats
 It must do at least 40 mpg

16. What have we learned?
 Ask questions
 Ensure no misunderstanding
 Confirm requirements
 Measurable
 Quantifiable

17. Requirements gathering
 I need a report showing current, good applicants.

18. Requirements gathering
 Applicant = flag in system
 Current = applied for intake to start September 2016
 Good = must have at least 3 predicted A Levels at AAA, AAB or
ABB

19. Tests
 Applicant = Yes
 Start Date > 1 September 2016
 Predicted grade tests x 4:
 AAA is included
 AAB is included
 ABB is included
 BBB is excluded

20. Anything else?

21. How do we test
 tSQLt
 Community tool
 Licence free
 Redgate SQL Test
 Fully licenced and supported product
 Part of the Developer suite

22. Using tSQLt
 Test Class
 All tests must start with the word ‘test’
 Names should define what’s being tested
 Tests should test 1 thing and 1 thing only

23. Test Object Hierarchy
GetListOfPracticalCars
GetListOfPracticalCars
Database object
Test Class
GetListOfPracticalCars.[TestAge] Test object
GetListOfPracticalCars.[TestPrice] Test object

24. How does this work?
 Fake everything
 Functions
 Data
 All other objects relied upon by the object tested

25. What is Test Driven Development
Test-driven development (TDD) is a software development
process that relies on the repetition of a very short development
cycle: first the developer writes an (initially failing) automated test
case that defines a desired improvement or new function, then
produces the minimum amount of code to pass that test, and
finally refactors the new code to acceptable standards. Kent Beck,
who is credited with having developed or 'rediscovered'[1] the
technique, stated in 2003 that TDD encourages simple designs and
inspires confidence.[2]
Taken from Wikipedia – Nov 2015

26. Demo

27. Downloads
 http://tsqlt.org/downloads/
 https://www.red-gate.com/products/sql-development/sql-test/

29. Contact me
 Annette@sqlsouthwest.co.uk
 @Mrs_Fatherjack