SWT2 2019/20 - Introductory Exercise

This is an interactive Ruby on Rails 5 exercise aimed introducing the basics of web development, used in the course SWTII. It is based partly on the offical "Getting Started with Rails" guide, so in case of getting stuck, that might be a good start to find solutions. The interactivity of this exercise is provided by opening issues in the GitHub issue tracker (through automation in a CI server). The tickets contain the currently failing test case and the corresponding error message as well as instructions on what tasks to tackle next.

This repository contains an application stub of an academic paper management system with a failing test case.

Follow these steps to complete the software and the exercise:

1) Set up your repository

• Log-in / Sign-up with travis-ci.com and enable automatic builds for your exercise repository

  • If you're having issues activating Travis, try using the following URL: https://travis-ci.com/swt2-intro-exercise/rails-exercise-19-YOUR_GH_USER_HERE (replacing YOUR_GH_USER_HERE with your GitHub user name)
  • It might be necessary to use the "sync account" function from your Travis CI account page

• Ensure that the issue tracker of the GitHub repository is active. This can be done in the repository's "Settings" tab on the GitHub website.

  

2) Set up local development environment

• Clone your exercise repository to your local machine using git clone. You might want to clone using SSH instead of HTTPS, to avoid having to type credentials when pushing.
• Please let the teaching team / your fellow students know if there are problems. Most likely someone else has had similar issues already and can help.

Option 1: Local setup on Linux or MacOS

• Change into the newly created directoy
• Inside the directory, check the used Ruby version using ruby --version. It should be 2.5.1. Other Ruby versions might work, but this is the one that was tested.
• If the correct Ruby version is not used, install a ruby version manager, for example rbenv using the instructions for rbenv installation and ruby-build installation.
  • WARNING: If you already have the Ruby version manager RVM installed, please use that or uninstall it prior to rbenv installation, as the two version managers are incompatible.
• Install Ruby version 2.5.1 with rbenv install 2.5.1 (this might take a few minutes, as Ruby is being compiled)
• The .ruby_version file in the repository instructs the ruby version manager to use the correct version.

Option 2: WSL in Windows 10

• Install the Windows Subsystem for Linux
• Install Ubuntu
• Follow the normal Linux installation instructions

Option 3: Use a Virtual Machine

• We recommend Virtualbox (as a VM provider) and Vagrant (to manage VMs) in combination with a Linux VM. Instructions can be found here. Any other container solution will most likely also work.
• In the container, follow the Linux install instructions.
• You may want to run the VM in a headless fashion, sharing file systems and using your locally installed tools:

  vagrant ssh #connect with VM
  cd <app_folder>
  rails s -b 0 #starting rails server, the -b part is necessary since the app is running in a VM and would otherwise drop the requests coming from the host OS

3) Dive into the code

• Run bundle install to install the dependencies of the project (they are stored in the Gemfile)
  • If the bundle command was not found, install bundler with gem install bundler
• Run rails db:migrate RAILS_ENV=development && rails db:migrate RAILS_ENV=test to migrate the database
• Start the development server (rails s) and check that the application runs (default: http://localhost:3000/)
• Run rspec to run the tests (RSpec is a test framework for Ruby)
• Write code to get the failing test to pass.

4) Commit and push

• When the tests pass on your local machine, push your changes to GitHub.
• Travis CI will test your project. You can check the state of the build on the Travis CI website.

5) Check your inbox / issues

• You will be notified of problems or new exercise work items via GitHub issues on your repository.
• While you wait, see where you could refactor your code, read the tutorial, or explore the project files.

6) For each issue

• Write a new test that documents the missing or failing behavior.
• Commit the failing test and reference the issue.
  • The commit message could be Failing test for #<ISSUE NUMBER>.
  • There is no need to push the failing commit.
• Fix the issue and make your test pass. Then commit the changes.
  • While an issue is open, the exercise will create comments on the issue, notifying you of errors

7) Repeat steps 4 to 6 until the exercise is complete.

Tips:

• The beginning of this exercise is designed to be solved while reading the official Getting Started with Rails Guide. When stuck, this should be your first read.
• Start the development server (rails s) and try out your app in the browser
• All available routes of the application can be displayed using rails routes
• For help with RSpec matchers, there is a Cheat Sheet or the documentation
• Run rspec spec/<path_to_spec>.rb to only run one set of specs
• Have a look at /spec/factories to get inspiration for your data model
• Besides generators and scaffolds, associations and validations are needed
• Look at the Mockup: https://gomockingbird.com/mockingbird/index.html?project=v890g6l#v890g6l/OQMURm (author selection uses a multiple select in this version of the exercise)
• rails db:drop && rails db:migrate deletes the database and recreates it. This might be helpful for error recovery.
• Make sure that all local changes are committed (git status) and pushed to the upstream repository (i.e., the one on GitHub) before the deadline