ESpec - Elixir Behaviour Driven Development

Hi, colleagues!

I’ve discovered this awesome forum recently and I wanna share my projects and ideas.
First of all, I create a topic about ESpec testing framework.
ESpec is inspired by RSpec Ruby library and implements its DSL.

There is also espec_phoenix project - a lightweight wrapper around ESpec which brings BDD to Phoenix web framework.

Let’s discuss your questions or proposals here!

Thank you!


Hi! I’ve never used Ruby (and therefore, RSpec) before, I’ve skimmed through the (quite long) readme and you said

It is NOT a wrapper around ExUnit but a completely new testing framework written from scratch.

I apologize for the basic question, but what exactly does ESpec have that ExUnit doesn’t? Why would I use it over ExUnit?

1 Like

I think it’s not necessarily a difference in functionality as much as style.

I don’t like calling Espec and Rspec BDD because I don’t think they are necessarily “pure” BDD like Cucumber is.

But the style is cleaner, the DSL is robust, and it tries to be “readable”. It basically has the same end result but a different way to get there.

Some people swear by RSpec in the Ruby world. Personally, I just used whatever I’m told to or what’s more convenient.

I do think that if you haven’t ever used a library with the expect/should you should. It definitely promotes a different way of thinking that causes you to write tests a little bit differently, which led me to write better tests overall.

Plus you may enjoy using that style better than an assert style.


Hi, Bobby!
Thanks for interesting in ESpec!
There are many cool features that present in ESpec but does not exist in ExUnit.
Just off the top of my head:

  • Nested context blocks with an ability to specify “before” block in each of them.
  • “let” macro which allows creating “memoizable” functions that caches result across multiple calls.
  • Built-in mocking functionality on top of Erlang “meck” library.
  • “Shared” and “generated” examples wich allows to avoid test duplication.
  • “Custom matchers” for testing specific functionality.

And, of course, the style of tests is different.
You may find some cool examples in ESpec spec folder or there are examples of using in Phoenix project


Hi, Azolo!
I completely agree with you.
ESpec suites have a different style that allows you better describe your test suites, thus making them more like “specification”.

1 Like

Are there any limitations of ESpec? For example, running tests in parallel or working with async gen servers?

Hi, @bzitzow! There are no any limitations. You can do everything you do with ExUnit and even more!)

I’m now reading the ebook Programming Phoenix 1.4 and when I see how they do the Integration test for the Controller. It’s very weird.
And now I’m seeking for the other possibilities and has a lot. I saw:
PhoenixIntegration.Requests and Hound very nice as well.

Hello. Is it possible to use ESpec with or something like guard for rails?

FYI I’ve successfully used ESpec with the JetBrains IDE test runner with the Elixir plugin. It will let you set the entire test suite to run, or a subset of the tests in a loop, monitoring for changes in the file system similar to Guard. You can even use it in debug mode where you can set breakpoints and interact with the state of the app in the middle of the test like PRY. Lately, though, I’ve migrated to purely Exunit tests.

If you are looking for a pure CLI tool, there are a few in the list here: Awesome Elixir | Curated list of awesome lists |

1 Like