Introduction

This is approximately the outline I use for a 3-day TDD course. I've used this outline in Java, C# and C++. How far I get depends on the students and the language. The flow can vary based on where the students want to go, their experience, etc.

Day 1

  • Basic TDD
    • Use Rpn Calculator to teach basic TDD
    • Create: plus, minus, factorial
    • Observe feature envy and fix by creating Operand Stack
    • Observe violation of OCP based on calculator interface and fix
    • Observe violation of SRP based on evaluation:
      • Introduce strategy
      • Introduce factory

Day 2

    • Observe violation of DRY and fix by introducing ABC + template method pattern
      • Use spy classes to build ABC without creating concrete subclasses
      • Update plus/minus to use
    • Have them create the following additional "operators"
      • Sum of all elements on operand stack
      • Prime factors
      • Introduce composite pattern, sum of prime factors, prime factors of sum
    • General pattern discussion
      • Everything is about polymorphism
      • Compare and contract
      • Design of pattern versus its intent
      • Discuss specific patterns students ask about
  • Clean Code
    • Change the structure of supplied code (and unit tests) - I could follow my colleague Bob Koss and do this first
    • Demonstrate refactoring after the students have done so
    • Discuss characterization tests
    • Discuss code smell: switch
    • Demonstrate refactoring to polymorphism/strategy pattern

Day 3

  • New problem (sometimes I intersperse this one with the sum of the stack and prime factors above): logging in
    • Introduce a mocking library (Rhino Mock for .Net and JMock 2 for Java - hand-rolled for C++).
    • Implement enough of this to discuss complexity of logic
    • Discuss state pattern
    • Refactor to patterns: state pattern
  • Wrapup