Testing Rails Applications

Testing Ruby on Rails applications isn't hard, but you have to learn the basics well. We'll cover how to write unit tests, system tests, integration tests and more. We'll also explore mocks, stubs, factories, fixtures, minitest vs rspec and much more.

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26 Lessons | 5h 20m | Intermediate

How to Test Validations in Rails

Sep 05, 2019

Learn how to write tests for validations on ActiveRecord objects in Ruby on Rails

13m

Test Driven Development Basics

Sep 10, 2019 Pro

Test Driven Development, or TDD, is a pretty simple process that allows you to write your code in conjunction with tests to ensure a high level of confidence and code coverage.

13m

How to use Fixtures to create sample test data

Sep 18, 2019 Pro

You can use Fixtures in Rails to create sample database records for your tests to run against. They're easy to setup and extremely quick.

How to use Devise Test Helpers

Sep 25, 2019

Adding Devise test helpers allows you to quickly login a user for testing controllers in Rails

14m

How to write Controller & Integration Tests in Rails

Oct 02, 2019 Pro

Learn how to write integration tests in Rails to test controllers and actions

13m

How to write System Tests in Rails

Oct 09, 2019

System tests allow you to use a browser for testing your Rails app including Javascript

14m

GitHub Actions with Ruby on Rails: Setting up Continuous Integration

Oct 17, 2019

Learn how to set up GitHub Actions to run Continuous Integration (CI) with Ruby on Rails

Testing API Integrations with WebMock

Oct 23, 2019 Pro

WebMock is a fantastic way to stub out and mock your HTTP requests. It will actually throw an exception in your test suite when an HTTP request is made so that you know when you're hitting an external API that you haven't stubbed out correctly.

10m

Testing External APIs with VCR

Oct 29, 2019 Pro

Testing integrations with external APIs in your Rails app can be hard. You don't know what requests are being made (or even the responses), so how can you properly mock them out? VCR to the rescue.

How to Test Background Jobs with Active Job

Nov 13, 2019

Learn how to test Active Job in your Ruby on Rails application

Testing Times & Dates with Rails

Nov 20, 2019

Rails provides several helper methods for testing times and dates in your applications. You can now freeze time and time travel like in the movies!

13m

How to test ActionMailer in Rails

Dec 02, 2019 Pro

Rails provides several really useful test helpers for ActionMailer so we can quickly iterate on our design, test that our code queues up the right emails, and make sure our emails contain the right content.

12m

Testing Rails ActionCable with Devise

Dec 09, 2019 Pro

Testing ActionCable authentication with Devise is pretty easy, especially when we build our own helpers to stub out Warden

Fixing Brittle Tests: Avoid Hardcoded Values

Dec 23, 2019

Test suites often become brittle over time where small changes end up breaking various tests. One way to avoid that is by avoiding using hardcoded values in your test suite.

How to use Test Stubs with Minitest

Dec 30, 2019 Pro

Test stubs are very handy when you want to mock out the response to a method call. This allows your tests to be more reliable and skip long running or unnecessary method calls.

How to use Mocks in Ruby tests

Jan 13, 2020 Pro

Mocks are a handy tool for writing tests in Ruby. You can use them to fake an object and verify that the correct methods were called against it. Perfect for testing a method that integrates closely with another class or module.

16m

Testing ActiveStorage File Uploads and Fixtures

Feb 17, 2020 Pro

Learn how to test ActiveStorage file uploads and create fixtures with ActiveStorage attachments

22m

Testing File Uploads in Rails with Shrine

Mar 23, 2020 Pro

Testing file uploads can be tricky, but Shrine makes both file uploading and testing a lot easier than you might expect.

11m

Code Coverage with SimpleCov and RailsBytes

Jun 23, 2020

Add code coverage to your app using SimpleCov and RailsBytes. We'll walk through installing simplecov and creating a RailsByte to automate it for us going forward.

13m

How to Test Gem Dependencies with Appraisal

Sep 03, 2020

Appraisal lets us test our code against different versions of dependencies. This is fantastic if you're building Rubygems that must work with multiple versions of Rails or other dependencies

14m

Testing against multiple versions of Ruby, Rails, and Databases with GitHub Actions

Nov 30, 2020 Pro

Testing a gem or your Rails app against multiple Ruby and Rails versions is super useful, but we also take it a step further and test our gem against several different databases too

15m

Using TDD To Fix A Bug In The Kredis Gem

Dec 06, 2021 Pro

I found a bug in the Kredis gem the other day and wanted to walk you through my thought process on debugging and using TDD to fix the bug for the future.

18m

System Testing File Uploads in Rails with Uppy and Dropzone Drag & Drop

Jan 26, 2022 Pro

Learn how to use system tests for file uploads with file input fields and drag & drop with Uppy and Dropzone

Testing Against Multiple Databases in Rails with The DATABASE_URL Env Var

Apr 11, 2022 Pro

Rails apps and Rubygems might need to support multiple databases. We can use the DATABASE_URL environment variable to quickly swap out the database that Rails uses in CI, local testing, and more.

16m

Testing a Meilisearch Integration with Ruby on Rails

May 02, 2022 Pro

Testing your Meilisearch integration in Rails can be a little tricky. This episode, we'll talk through how to setup Meilisearch in your test suite to index fixtures and more.

13m

Authentication Generator Test Helpers

Jun 09, 2025

The Rails Authentication generator is getting new test helpers. We'll take a look at how to use them with integration tests and how to extend them to work with system tests too.

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