When we start developing an app we usually do it the old fashion way: we get an idea, we elaborate on it, we make a plan to develop an app then we start coding and in the end, we test if our app is working properly. Nothing is wrong with that approach but, there are some features that we can not test with it and sometimes it will be very hard and time-consuming to debug the code and find the errors we have, sometimes also we end up writing more code than needed. Therefore, the test-driven development or TDD came out to the surface which is a software development process that works as follows: Thinking about the idea, designing and developing tests for every small functionality of the app and expecting the desired result (tests will be failing), then write code to make the tests work, and finally refactor the code to be more readable and maintainable and repeat. The TDD workflow (Red / Green / Refactor cycle): The process described above is called the “Red, Green, Refactor cycle” and it works as follows: Analyze the problem then write the test (which will fail because we do not have the code to make it work yet). Red: Write just enough code to make the test pass. Green: Improve the code design and always refactor in green. Refactor: TDD structure (the AAA): The AAA stands for “Arrange, Act and Assert”: It consists of the preparations to start testing like initializing or instantiating objects, setting up mocks and stubs, defining let variables using factories …etc. Arrange: To predict the behavior expected from the tested object while it is in use, for example, to visit a page then click a button or to build a post then try to save it calling the appropriate methods and execute the behavior we want to test. Act: To expect the actions and methods used in the “Act” phase to produce the desired results and compare the two. Assert: Testing with RSpec: RSpec is a testing tool written in Ruby and used to test it. It is the most frequently used testing library for Ruby in production applications, it is widely used to test Ruby on Rails apps using the TDD approach. RSpec basics: Some important RSpec basics to jump-start into using it, it works with the AAA structure that I previously explained: Define the variable or instantiate the object.Use the desired methods on it.Expect it to equal something that you set. Example: To avoid repetition: You can use a method with a block, and instantiate the object inside it with a before its name and use it that way everywhere in the test. Before do…it ‘@’ Example: before @variable = Classname.new do end 2. You can also use with a symbol to name the variable and instantiate the object inside its block (let is lazy and it will cache the variable in the first use and use it from the cache if we use it again). let Example: let( ) { Classname.new } :variable Using RSpec and Capybara in Rails In Ruby on Rails, there are many testing frameworks like the default one that comes with the new Rails projects or the ones that I’m writing about in this article and which I will explain a how to set them up in a new Rails project and show some basic uses of the two. Minitest RSpec Capybara Setting up RSpec and Capybara on rails: Initialize a new rails app without the default run the following command: $ minitest rails new -T <name of the app> Add the following gems to the development group in the : Gemfile ‘Rspec-rails’, ‘factory_bot_rails’, ‘spring-commands-rspec’ Add a new group named and put the following gem inside it: test ‘Capybara’ Run to install the gems.In the terminal and after to the new app run: $ to install . $ bundle install cding rails g rspec:install RSpec Then run to generate for all the files. $ bundle exec spring binstab — all binstab Create the first test file ending with at the end and in the first line of every spec file. _spec.rb require “rails_helper” These two steps may be helpful in some cases: Optional: Open the file in your project and add: to enable colored previews. .rspec — color Add to the same file to get more details when you run the tests. — format documentation To run the just run the command: in the terminal and you will see something similar to the below image: RSpec $ rspec Testing basics: To write a simple test we have to follow the below steps: 1. Make a file for the unit or the feature to be tested or open the one generated automatically by Rails if that’s the case. _spec.rb 2. You start with a block that can take a string or a Class. describe 3. You can indent many blocks together but the better practice is to use instead for the inner blocks. describe context 4. To test the different methods and functionalities of a class use the block that takes a string as a description. it 5. Write your tests inside the block. it 6. Run the command to only test the wanted file, or you can omit the name to run the whole test suite. $ bundle exec rspec <file name> Test types in rails: There are 3 different kinds of tests in Rails Testing Models or different units and parts of the app to make sure they work properly, Testing for the presence and validations of a model. Unit tests: E.g: Test that units or features communicate properly together and produce the expected results. Testing the user’s sign up functionality and checking if it saves a new record to the database. Integration test: E.g: To test the whole application and the user interface UI. Acceptance tests: Using RSpec and Capybara in rails: 1. RSpec (Unit and controller tests): Usually, it is used for , checking if the validation is properly working, if the associations are properly set in both the correct and incorrect cases.It is also used to test controllers, checking if all the different actions are properly working and doing what they were created to do, giving the expected results, but I prefer skipping the controllers’ tests and just do it in the integrations since it will check kind of the same thing. unit tests 2. Capybara (integration / feature tests): Usually, it is used for integration tests that make use of a form, we use which has a slightly different syntax, in becomes and becomes . Capybara Capybara describe feature it scenario With we can make use of the forms easily just filling in the fields with the desired information and expecting the correct or the wrong result as in the below image: Capybara Conclusion Developing a good app requires good maintainable, bug-free code, something that is hard and takes a long time to achieve using the standard development workflow if it is a big app, but implementing the workflow and using tests with or make our life much easier, saves up time debugging and makes the code more professional, maintainable and human-readable. TDD RSpec Minitest Resources for more about TDD and RSpec The following websites are great if you’d like to learn more about and testing in Ruby on Rails: RSpec https://www.tutorialspoint.com/rspec/index.htm http://www.betterspecs.org/ https://www.oreilly.com/library/view/test-driven-development/0321146530/ PS: Thank you for reading and if you liked my article I would appreciate it if you follow me on twitter ( https://twitter.com/redvanisation ) so you get notified about any new articles I post in the future.

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