test driven development
TRANSCRIPT
About Testing!
Test Last or DDD (Design Driven Tests)
Short development iterations
Is a design process
Based on requirement and pre-written test cases
Tests are your first users
The goal is to produce working clean code that fulfills requirements
If TDD hurts then you're doing it wrong
Unnecessary Codes
Unchangeable Codes
Unintelligible Code
Makes you think about required behavior.
Provides documentation.
Improves quality.
Reduces speculative code.
Less time debugging.
Confidence in change
Discover usability issues early
I don’t have time to unit test.
The client pays me to develop code, not write unit test.
I am supporting a legacy application without unit tests.
QA and User Acceptance Testing is far more effective in finding bugs.
I don’t know how to unit test, or I don’t know how to write good unit tests.
It forces you to really understand the code.
It forces you to really understand the tests
It forces you to create code that is truly reusable and modular and testable
These forces drive you to keep your code and your tests simple and easy to understand.
Enabling TDD
TDD Cycle
Choosing the First Test?
Green Bar Patterns
State-based vs. Interaction-based Unit Testing
NUnit
MbUnit
VSTS
xUnit.net
Moq
Rhino Mocks
Resharper
TDD.NET
Refactor Pro!
Visual Studio
create a
failing
test
write
just
enough
to pass
remove
duplicatio
n clarify
intent
RED
GreenRefactor
The simplest.
The essence.
If you need to write code that is untested, choose a simpler test.
If the essence approach takes to much time to implement, choose a simpler test.
Small and focused
Intention revealing
Repeatable
Independent
Have no side-effects
Description should be
• Domain-specific
• Suitable for customer comprehension
• Understandable in absence of code
Writing descriptions
• Think about behavior
• Think about the context of the behavior
• Focus on the words, not the implementation
Fake It(Til You Make It)Start with hardcoded results and wait until later tests to force them to become real.
Triangulate To AbstractionMake the code abstract only when you have two or more examples.
Obvious Implementationaka Don't Be Stupid
If you really, really, honestly know the right way to implement it, then write it that way.
