Software Engineering Lecture #12

Software Engineering Lecture #12

• Software development is divided into phases: Requirements, Design, Coding (Implementation), Testing, and Maintenance.
• Requirements define what the software should do.
• Design outlines the software's components and how they interact.
• Coding (Implementation) translates the design into code that instructs the computer.
• Testing verifies if components meet requirements and the entire system functions correctly.
• Maintenance involves adding features and fixing bugs after development is complete.

Requirements Phase

• Goal: Understand user needs.
• Methods: Speak with the client, understand necessary hardware and software, and document everything.
• Problems: Clients may not clearly state their needs, or use different terminology.
• Solutions: Document everything, including prototypes, to ensure mutual understanding.

Functional and Non-Functional Requirements

• Functional requirements: Define the behavior or what the system should do.
  • Example: A system should send an email when an order is placed.
• Non-functional requirements: Specify constraints on how the system should function.
  • Example: Emails should be sent within 12 hours.

Prototyping

• Developers create prototypes before beginning the complete application development.
• Prototypes help understand the product functionality and how it will work.

Software Design

• Design is about how the program's components will be created and interact.
• Critical questions to answer during this phase: Operating System, Libraries/frameworks, and Classes.

Coding Phase

• Focus: Coding, using version control, and appropriate comments.
• Key points:
  • Version control is crucial.
  • Developers should define coding standards and comments.
  • Regular review meetings improve code quality and identify potential errors early.

Version Control Systems

• Version control systems maintain the history of files and allow reverting to previous versions.
• Example systems include Git, SVN, and Mercury.

Git

• Git is a version control system.
• It creates snapshots of files (versions) locally.
• Versions can be uploaded to a repository (like GitHub).
• Important Git commands: - git clone: copies a repository. - git add, git add ., git add *.txt: adds files and /or all files to the repository. - git rm: removes files from the repository. - git commit -m "message": saves changes in the repository with an accompanying message. - git push : uploads changes to the remote repository. - git pull : downloads changes and files from a remote repository.

Git examples

• git config -global user.email "[email address]" sets the user's email address.
• git init [repository name] initializes a local repository.
• git add file: adds a file to the staging area.
• git commit -m "[description]" saves changes to the repository.
• git remote add origin [link] sets up a remote repository.
• git push -u origin master pushes changes to the remote repository.

Git commands

• git diff: Shows differences between files.
• git log --oneline: Displays a list of commits.
• git checkout fc53bcd: Checks out a specific commit.
• git checkout master: returns to the current version.
• git reset --hard 79f0fa3: goes back to an older commit.

Testing

• Testing is checking the program for errors.
• Testing is now often automated.
• Testers write tests and the tests are a crucial part of software development

History of Software Testing

• In the past, testing was often done manually and not prioritized as critically.
• Now, testing is done more frequently and is often automated to catch and find errors more early.

Unit Testing vs. Integration Testing

• Unit testing: Checks individual components.
• Integration testing: Checks how different components work together.

TDD (Test-Driven Development)

• Write tests before writing the actual code.
• Write enough just to pass the tests.
• Refactor to improve code quality and solve issues.

Selenium

• Selenium is software used for testing user interfaces.
• Allows for automated browser manipulations to check various functionality of the application.

Unit Tests(Java)

• Example setup of a unit test demonstrating adding two numbers.

Maintenance

• Maintaining software (application) includes adding new features and fixing bugs.

Waterfall vs Agile

• Waterfall model: A sequential software development model, where each phase must be completed before moving to the next.
• Agile model: An iterative software development model.