1. xUnit Style Database Unit Testing ACCU London – 20 th January 2011 Chris Oldwood gort@cix.co.uk

2. Presentation Outline Database Development Process The xUnit Testing Model Test First Development Continuous Integration/Toolchain Pub

3. Legacy Database Development Shared development environment Only integration/system/stress tests No automated testing Only real data not test data Referential Integrity – all or nothing No automated build & deployment

4. Ideal Development Process Isolation Scaffolding Automation

5. Example Testable Behaviours Default constraint Trigger to cascade a delete Refactoring to a surrogate key

6. NUnit Test Model [TestFixture] public class ThingTests { [Test] public void Thing_DoesStuff_WhenAskedTo() { var input =...; var expected =...; var result =...; Assert.That(result, Is.EqualTo(expected)); }

7. NUnit Test Runner Tests packaged into assemblies Uses reflection to locate tests In-memory to minimise residual effects Output to UI/console

8. SQL Test Model create procedure test.Thing_DoesStuff_WhenAskedTo as declare @input varchar(100) set @input =... declare @expected varchar(100) set @expected =... declare @result varchar(100) select @result =... exec test.AssertEqualString @expected, @result go

9. SQL Test Runner Tests packaged into scripts (batches) Uses system tables to locate tests Uses transactions to minimise residual effects Output to UI/console

10. SQL Asserts Value comparisons (string, datetime, …) Table/result set row count Table/result set contents Error handling (constraint violations)

11. Setup & Teardown Per-Fixture (static data) Per-Test (specific data) Use helper procedures

12. Default Constraint Test create procedure test.AddingTask_SetsSubmitTime as declare @taskid int declare @submitTime datetime set @taskid = 1 insert into Task values(@taskid,...) select @submitTime = t.SubmitTime from Task t where t.TaskId = @taskid exec test.AssertDateTimeNotNull @submitTime go

13. Trigger Test create procedure DeletingUser_DeletesUserSettings as... set @userid = 1 insert into AppUser values(@userid,...) insert into AppUserSettings values(@userid,...) delete from AppUser where UserId = @userid select @rows = count(*) from AppUserSettings where UserId = @userid exec test.AssertRowCountEqual @rows, 0 go

14. Unique Key Test create procedure AddingDuplicateCustomer_RaisesError as... insert into Customer values(‘duplicate’,...) begin try insert into Customer values(‘duplicate’,...) end try begin catch set @threw = 1 end catch exec test.ErrorRaised @threw go

15. Automation Enables easy regression testing Enables Continuous Integration Performance can be variable

16. Test First Development Start with a requirement Write a failing test Write production code Test via the public interface

17. The Public Interface Stored procedures Views Tables?

18. Implementation Details Primary keys Foreign keys Indexes Triggers Check constraints Default constraints

19. Deployment Testing Build version N+1 then run unit tests Build version N then patch to N+1 then run unit tests ==

20. Buy or Build? Batch file, SQL scripts & SQLCMD TSQLUnit & PL/Unit Visual Studio SQL Server/Oracle Express

21. “The Oldwood Thing” http://chrisoldwood.blogspot.com Chris Oldwood gort@cix.co.uk