2. AMIR BARYLKO
TDD PATTERNS
FOR .NET DEVELOPERS
PRAIRIE DEV CON
REGINA 2010
Amir Barylko - TDD Patterns MavenThought Inc.

3. WHO AM I?
• Architect
• Developer
• Mentor
• Great cook
• The one who’s entertaining you for the next hour!
Amir Barylko - TDD Patterns MavenThought Inc.

4. WHY TDD?
• Test first approach
• Quality driven
• Easy to refactor
• Regression tests as byproduct
• Increase developer’s confidence
Amir Barylko - TDD Patterns MavenThought Inc.

5. SETUP
Amir Barylko - TDD Patterns MavenThought Inc.

6. TOOLS
• Testing framework: NUnit, MbUnit, MSpec, MavenThought Testing
• Mocking framework: Rhino Mocks, Moq, TypeMock
• Test Automation: Scripts that can run the test from the
developer computer.
• CI server: Unit test should be run after each commit.
• Reports and Notifications: The team should realize right away
that the tests are broken.
Amir Barylko - TDD Patterns MavenThought Inc.

7. AUTO MOCKING
• Automatic dependency creation for SUT
• Dictionary of dependencies
• Faster setup of tests
• Build your own: StructureMap
• Or use MavenThought Testing
Amir Barylko - TDD Patterns MavenThought Inc.

8. PATTERNS
Amir Barylko - TDD Patterns MavenThought Inc.

9. ONE FEATURE PER TEST
• Easy to approach Given That
(arrange)
• Easy to understand
When I Run
• Easy to maintain
(act)
• Enforce Given, When, Then
Then it should ...
(assert)
Amir Barylko - TDD Patterns MavenThought Inc.

10. STATE VERIFICATION
• Care about the end state var m = new Library...
• Does not validate SUT
transitions Run Test
• Verifythe state agains the
m.Count.Should(...)
expected value
Amir Barylko - TDD Patterns MavenThought Inc.

11. BEHAVIOUR VERIFICATION
• Checking the expected var m = Mock<...>
behaviour happened
• Uses mock objects m.Stub(...)
• The behaviour is specified
for each mock object Run Test
• The expected methods
m.AssertWasCalled(...)
should be called
Amir Barylko - TDD Patterns MavenThought Inc.

12. TEST WITH PARAMETERS
[Row(1)]
• Avoid duplication and [Row(2)]
repetition void Method(int arg)
[Row(typeof(...))]
• Generic Parameters void Method<T>(...)
• Parameters Factories [Factory(...)]
void Method(string arg)
• Random strings void Method([Random]...)
• Random numbers void Method([Random]...,
[Factory]...)
Amir Barylko - TDD Patterns MavenThought Inc.

13. DEPENDENCY INJECTION
• Remove hardcoded Initialize dependency
dependencies
• Introduces dependency in Stub dependency with
the constructor / setter mock
• Easy to test and maintain
Assert the mock is
returned
•S OLID
Amir Barylko - TDD Patterns MavenThought Inc.

14. DEPENDENCY LOOKUP
• Remove hardcoded Initialize service
dependencies locator
• Introduces a factory or Stub to return a mock
service locator
• Easy to test and maintain Assert the mock is
returned
•S OLID
Amir Barylko - TDD Patterns MavenThought Inc.

15. DATABASE SETUP
• Base class to setup the Create Database
database
• The test always works with a Populate
clean database
• Can be configured to Store
populate data if needed
Retrieve and Assert
Amir Barylko - TDD Patterns MavenThought Inc.

16. QUESTIONS?
Amir Barylko - TDD Patterns MavenThought Inc.

17. RESOURCES
• Contact me: amir@barylko.com, @abarylko
• Download: http://www.orhtocoders.com/prairiedevcon
• Books: The rSpec book, xUnit Patterns.
Amir Barylko - TDD Patterns MavenThought Inc.

18. RESOURCES II
• NUnit: http://www.nunit.org
• Gallio & MbUnit: http://www.gallio.org
• MavenThought Testing: http://maventcommons.codeplex.com
• Rhino Mocks: http://www.ayende.com
• StructureMap: http://structuremap.sourcefore.com
• TeamCity: http://www.jetbrains.com
Amir Barylko - TDD Patterns MavenThought Inc.