1	The Software Craftsman Keith Alcock TCS DevSig July 2, 2002
2	I. Introduction
3	Source Software Development of July 2002 in article called “Opening Disaster” by Robert Martin The forthcoming book Principles, Patterns, and Practices of Agile Software Development (Prentice Hall, 2002)
4	Query Who subscribed to the magazine? Who has read the article? Who looked at the web page? Who has seen Smalltalk version of code?
5	Cast Apprentice: Alphonse Journeyman: Jerry Master craftsman: Mr. C.
6	Act I: Orientation
7	Scene I: Alphonse codes Assignment Sieve of Eratosthenes Unit tests Constraints Java language Due after lunch Meets standards of Mr. C. Preliminary results Complete and under schedule
8	Scene II: Jerry reviews 5-minute silent code review Step-by-step walkthrough Preliminary results Does not meet Mr. C’s standards Long method identified Refactoring suggested
9	Topics Code reviews Refactoring Unit testing
10	Methods Overview Discussion Hands-on
11	II. Code review
12	Source Handbook of Walkthroughs, Inspections, and Technical Reviews by Freedman and Weinberg (Dorset House, 1990) Extreme Programming Explained by Kent Beck (Addison Wesley, 2000)
13	Query Who has read either book? Who has done code reviews? Who read the handout from a previous meeting? Who does XP or Agile?
14	Rationale “Point out needed improvements in a product of a single person or team.” “Confirm those parts of a product in which improvement is either not desired or not needed.” “Achieve technical work of more uniform, or at least more predictable, quality than can be achieved without reviews, in order to make technical work more manageable.”
15	Additional benefits Assure that more than one person has seen each part of the projects and has a basic understanding of it Identify reusable components within a project or across projects Provide data on common mistakes that can then be used in testing Locate areas where code or function is duplicated
16	Example guidelines Pretty print code to standard format Code should compile and run Reviewers must be prepared Identify problems and correct them in different steps Find good things as well as bad
17	Example materials Program listing Checklists for common problems Style manuals Pattern guides Design documents CRC cards UML diagrams Report forms
18	Roles Review leader Recorder Reviewers Author
19	III. Refactoring
20	Source Refactoring by Martin Fowler (Addison Wesley, 2000) www.refactoring.com/
21	Query Who has read the book? Who has used automated tools?
22	Definition “Refactoring (noun): a change made to the internal structure of software to make it easier to understand and cheaper to modify without changing its observable behavior.” “Refactor (verb): to restructure software by applying a series of refactorings without changing its observable behavior.”
23	Rationale Improves the design Simplifies the software Helps identify errors Prevents decay
24	Timing When adding functionality During debugging For code review To avoid the third strike
25	Example problems Duplicated code Long method Long parameter list Comments Lazy class
26	Example solutions Extract method Replace magic number with symbolic constant Rename variable Introduce explanatory variable
27	Tools Refactoring browser Unit testing framework
28	IV. Unit testing
29	Source Article “Simple Smalltalk Testing: With Patterns” by Kent Beck www.xprogramming.com/software.htm
30	Query Who has used SUnit or JUnit?
31	Unit For purposes of unit testing with object-oriented languages, unit most often means a class. “Classes should contain their own tests.”
32	Components Fixture Configured instance of class to be tested Test case Stimulus used for the test Check Code to check results of the test Test suite Collection of tests
33	Results Pass No failure or error detected Failure Anticipated problem Error Condition that wasn’t checked
34	Example guidelines Write tests based on risk factor Tests should be fully automatic Tests should check their own results Don’t be a completionist
35	V. Summary
36	Craftsman A craftsman is a person who makes or manufactures (e.g., software) with skill and careful attention to detail Some of the skills include knowing how to review code, refactor, and test.