The document provides an overview of strategies for software development including data structures, testing approaches, managing complexity, source code management, licenses, and algorithms. It discusses common data structures like arrays and lists. It outlines best practices for testing including unit testing, test-driven development, and continuous integration. It also covers techniques for managing complexity through abstraction, simplifying assumptions, and refactoring code. Source code management tools like Git and SVN are explained as well as hosting services like GitHub. Finally, it briefly introduces common open source licenses and algorithm efficiency measures.

1. MAS.500 - Software Module - Rahul Bhargava
Software Dev
Strategies
2014.11.12

2. Data Structures
Testing
Managing Complexity
Source Code Management
Licences
Algorithms

3. Data Structures

4. ❖ Array
❖ HashMap/Dictionary/AssociativeArray
❖ List
❖ Queue (FIFO)
❖ Stack (LIFO)
❖ Tree (parent/children)
❖ Graph (node/vertex)

5. Testing

6. Approaches
❖ Motivations
❖ Make sure individual pieces of your project work, before sticking
them together
❖ Ensure changes in one part of system haven’t broken another part
by mistake
❖ Strategies
❖ Unit Testing, Functional Testing, Integration Testing
❖ Technologies
❖ xUnit (ie. jUnit for Java, pyUnit for Python, Test::Unit for Ruby, etc)

7. Unit Test Anatomy
❖ Load up some test data
❖ Run some piece of your code on your test data
❖ Verify the result is correct
❖ Remember to test the multiple valid paths through your
piece of code, not just the most likely one (ie. test edge
cases too)
❖ demo

8. Strategies
❖ Test Driven Development
❖ Write your tests before your code?
❖ Continuous Integration
❖ Automated build/test cycle, all day long
❖ Pair Programming
❖ Two heads are smarter than one?
❖ 80/20
❖ Write tests for the most critical low-level parts of your system

9. Managing Complexity

10. It’s Easy to Remember Less
❖ Abstraction
❖ Higher level commands are easier to use
❖ Simplifying assumptions
❖ Convention makes things easier to guess
❖ Readability
❖ Remember WTF something does 6 months later
❖ Commenting
❖ Focus on the why, not the what

11. Reminders
❖ “Refactor” Constantly
❖ Change how your code does what it does to reflect things you learn
❖ Keep the “Technical Debt” (video) approach in mind
❖ Text Editors, Integrated Development Environments (IDEs)
❖ Can help, or hurt, your code process
❖ Some Examples: PyDev, Eclipse, Xcode, Visual Studio, Mono
Develop, Aptana Studio
❖ IDE demos

12. Source Code Management

13. SCM
❖ Motivations: cover-your-rear, collaborate on code,
control deployment
❖ Technologies: CVS (old school), SVN (centralized), git
(distributed)
Server
Sally Bob

14. SCM: Process
git (with a server)
• Clone repository to your computer (only
once)
• Change code
• Commit changes locally
• Pull changes from server
• Merge any conflicts
• Commit fixes locally
• Push all commits back to server
Learn More:
git-scm.com/book/en/Getting-
Started-Git-Basics
SVN
• Checkout code to your computer (only
once)
• Change code
• Update code to get any changes from the
server
• Merge conflicts
• Commit changes back to server
Learn More:
http://svnbook.red-bean.
com/en/1.6/svn.basic.in-action.
html
…lets not relive the dark days of CVS…

15. SCM: Example
❖ Setup
❖ With git you usually have to set up SSH keys first for authentication
❖ Clone the project to get the repository from the server to your computer
❖ git clone git@github.com:username/project.git
❖ Process
❖ Make your changes (for example, edit README.txt)
❖ Stage the changes that you want to commit
❖ git add README.txt
❖ Commit the changes
❖ git commit –m “Better instructions”
❖ Push the changes to the main branch (master) on the server (origin)
❖ git push origin master

16. DEMO

17. Handling Conflicts
❖ Structuring your source files well helps avoid conflicts
❖ Using MVC can help (see later slides)
❖ Uh oh, we both changed same part of the README.txt!
❖ When if happens, open the file and find the conflict:
❖ <<<<<<<< HEAD:README.txt
❖ My code here
❖ =================
❖ Other person’s new code here
❖ >>>>>>>>>>> [their_version]:README.txt
❖ Pick which version to keep and delete the other stuff
❖ Read more in the gitbook
❖ git-scm.com/book/en/Git-Branching-Basic-Branching-and-Merging#Basic-Merge-Conflicts

18. SCM: Tags and Branches
❖ Tags - take a snapshot of your repository at a certain
point in time
❖ Useful for deploying specific snapshots of code that
you know work to a server/demo-box
❖ Branches – work on side projects without affecting your
main development
❖ git makes merging branches easier, but should still be
done carefully

19. SCM: Repo Hosting
❖ Necsys can host repositories
❖ http://wiki.media.mit.edu/view/Necsys/MediaLabGITServer
❖ http://www.github.com
❖ public, social, issue tracking, project maps 1-to-1 onto repository
❖ mit has an enterprise site license (http://github.mit.edu/)
❖ http://gitorious.com
❖ Open source, organized by projects with multiple repositories
❖ http://code.google.com
❖ http://sourceforge.net

20. SCM: Desktop Tools
❖ command line
❖ Tortoise for Windows:
❖ http://tortoisesvn.net
❖ http://code.google.com/p/tortoisegit/
❖ GitHub for Mac
❖ http://mac.github.com
❖ GitBox for Mac
❖ http://www.gitboxapp.comh
❖ Eclipse

21. SCM: GitHub
❖ online hosting
❖ ssh keys

22. Licences

23. http://marakana.com/s/post/1030/understanding_open_source_licenses

24. http://www.shafqatahmed.com/2008/10/comparison-of-d.html

25. Algorithms

26. ❖ Measured based on efficiency (good examples)
❖ Fixed time: O(1) - Fast!
❖ Pull the 10th value out of an array
❖ Log time - O(log n) - Scales well!
❖ Find a number in a sorted array via binary search
❖ Linear time: O(n) - Does ok!
❖ Sum an array of numbers
❖ Exponential time: O(2n) - Scales poorly!
❖ Graph traversal stuff

27. Homework
❖ see course outline: bit.ly/mas500f14