1. Presented by: Ben Palermo Nathan O’Grady

2.  How to Program by Coincidence  Accidents of Implementation ◦ It may just look like its working ◦ The boundary conditions may be an accident ◦ Behavior may change with the next library release ◦ Superfluous code makes execution time longer ◦ Extra calls increases the chances of new bugs  Accidents of Context  Implicit Assumptions

3.  Be aware of what you are doing  Understand the project and the language  Use a plan  Only rely on what you know for sure  If you must assume, document it  Test your assumptions, as well as your code  Spend time on the important things  Do not be afraid to rewrite existing code

4.  O() notation  Estimation ◦ Simple Loops ◦ Nested Loops ◦ Binary Chop ◦ Divide and Conquer ◦ Combinatoric  Algorithm speed in practice

5.  What is refactoring?  When to refactor ◦ When two units perform the same action ◦ Non-orthogonal design ◦ New requirements or a better understanding of the problem ◦ Improving performance

6.  Complications ◦ Pressure to release a product ◦ Refactor early, refactor often

7.  How to refactor ◦ Refactoring is redesign ◦ Don’t refactor and add functionality ◦ Establish good tests before refactoring ◦ Make small, deliberate changes  Test after each change ◦ Let refactoring changes break old builds

8.  Unit Testing ◦ Testing done on individual modules in isolation to each other ◦ Creates artificial environment, then tests output based on known values

9.  Using contracts ◦ Design unit tests to check that a contract is fulfilled ◦ Test modules in a bottom-up approach ◦ Design code to be tested (i.e. design with contracts in mind)

10.  Writing Unit Tests ◦ Include in main source code  As a separate, normally unused function ◦ Use test harnesses  JUnit test cases  Composable tests  Include a debugging window in final build  Culture of Testing

11.  Don’t use wizard code you don’t understand.  Be able to write wizard code without the wizard.