Find out how you can time travel in your tests with Rail’s travel_to helper
Rail, an open source web application framework built on top of Ruby, is a great platform for developers to create applications quickly and easily. The framework has powerful tools that help developers manage and maintain their applications, such as the Active Record Object Relational Mapper (ORM) and Active Support Core Extensions.
More recently, Rail introduced the travel_to helper, which allows developers to easily time travel in tests. This new feature is useful for multiple scenarios, from simulating delayed API responses to testing the timing of a background job. Today we’ll explore how you can use the travel_to helper to take control of time in your tests!
When writing integration or system tests you might need to test against real-time data or have some logic triggered after a certain amount of time has elapsed. For example, you might need to test if an automated email is being sent out after 10 minutes have passed since an event occurred. With the travel_to helper you can easily stub out these types of scenarios without messing up your server’s actual time zone settings.
Using travel_to couldn’t be simpler – it works just like any other RSpec helper method or matcher: all you need to do is provide it with one argument – a DateTime object specifying the date and time you want your fake “clock” to be set at- and Rails will automatically handle freezing the clock at that point in time until you reset it back (e.g., by calling Timecop#reset).
As an added bonus, Rails also provides two method aliases – travel (with no underscore)– which lets you pass either a DateTime or a number of seconds as its argument – and now (also with no underscore) –which sets the simulated time to DateTime#present. This makes it even easier for developers perform tests!
If there are global shared state variables affecting our domain objects after certain periods of ‘real world’ time have passed then we should consider creating helpers around this functionality in order for us to ensure our code does not rely on non deterministic behaviour during different times when executing tests e.g., background jobs being triggered; transactions committing outside of expected windows etc… By utilising both Travel To Helper and Time Cop extension we can define static points in our system (which move independently from real world clock) along timeline allowing us easy way exercising deterministic behaviour without actually caring what the current operating system’s clock setting happens – essentially turning off effects that normal Date/Time casts onto our systems during testing runs.
In conclusion, using Rails’ travel_to helper is an invaluable tool for managing your applications’ logic over different points in time during integration/systems testing. Its Aliases makes testing this type of scenario even easier by providing two quick shortcuts – `travel`and `now` – so developers can write concise yet powerful test cases without having worry about messing with their server’s environment settings or manually supplying more complex arguments like seconds or hours instead of Dates & Times . If used alongside Timecop extension it should allow us exercising deterministic behaviour ensuring stable testable state across multiple development iterations regardless what current OS Clock happens draw attention too creating true end results accuracy thus efficient bug free production release cycle workflow processes .