Your Turn

In this chapter, we looked at two ways to configure RSpec: the command-line options and the configure method. Command-line options are easy to discover, and they’re great for one-off changes to RSpec’s behavior. The configure method covers more of RSpec’s behavior and gives you finer-grained control over how RSpec runs.

We’re not asking anyone to memorize the entire set of configuration options. But the ones we’ve shown you here will help you turn RSpec into a comfortable, productive working environment.

Exercises

Now that you’ve seen what a wide array of configuration options RSpec offers, try your hand at using a few of them in these exercises.

Using a Custom Formatter

Find and read the documentation for the following RSpec formatters (some of which are more useful than others):

• Fivemat^[74]
• Fuubar^[75]
• NyanCat^[76]
• Any others you can find

Install a couple of these gems onto your system. Try each formatter at the command line with one of your projects; the expense tracker app you wrote in the second part of this book would be perfect.

Once you’ve found a formatter you like, configure one of your projects to use it on every run. If you really enjoy using this formatter, you may want to configure RSpec to use it on all your projects.

Detecting Slow-Running Specs

As we’ve discussed before, keeping your specs running quickly is key to achieving a productive flow. In this exercise, you’re going to write a library that will measure some of your specs’ execution times and fail any example that’s too slow.

You don’t want to apply the same timing requirements to all your specs—after all, integration and acceptance specs are typically slower than unit specs. Your library should use a piece of configurable metadata, such as :fail_if_slower_than, to set the threshold. For instance, any example in the following group should fail if it takes longer than a hundredth of a second to run:

Users will be able to configure these thresholds automatically for whole sections of their suites, using the techniques in ​Derived Metadata​.

When your library first loads, it should define an around configuration hook. The hook will compare the wall clock time before and after each example runs, and then fail the example if it takes too long.