CLI Steps for Cucumber
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Aruba is Cucumber extension for Command line applications written in any programming language. Features at a glance:

  • Test any command line application
  • Manipulate the file system
  • Create great HTML documentation based on your own Cucumber scenarios


If you have a Gemfile, add aruba. Otherwise, install it like this:

gem install aruba

Then, require the library in one of your ruby files under features/support (e.g. env.rb)

require 'aruba/cucumber'

You now have a bunch of step definitions that you can use in your features. Look at lib/aruba/cucumber.rb to see them all. Look at features/*.feature for examples (which are also testing Aruba itself).


Aruba has some default behaviour that you can change if you need to.

Use a different working directory

Per default Aruba will create a directory tmp/aruba where it performs its file operations. If you want to change this behaviour put this into your features/support/env.rb:

Before do
  @dirs = ["somewhere/else"]

Modify the PATH

If testing an executable in your project's bin directory, it might not be in the PATH Aruba uses. An easy way to set it is to put the following in features/support/env.rb:

ENV['PATH'] = "#{File.expand_path(File.dirname(__FILE__) + '/../../bin')}#{File::PATH_SEPARATOR}#{ENV['PATH']}"

Increasing timeouts

A process sometimes takes longer than expected to terminate, and Aruba will kill them off (and fail your scenario) if it is still alive after 3 seconds. If you need more time you can modify the timeout by assigning a different value to @aruba_timeout_seconds in a Before block:

Before do
  @aruba_timeout_seconds = 5

Increasing IO wait time

Running processes interactively can result in race conditions when Aruba executes an IO-related step but the interactive process has not yet flushed or read some content. To help prevent this Aruba waits before reading or writing to the process if it is still running. You can control the wait by setting @aruba_io_wait_seconds to an appropriate value. This is particularly useful with tags:

Before('@slow_process') do
  @aruba_io_wait_seconds = 5


Aruba defines several tags that you can put on on individual scenarios, or on a feature.

Seeing more output with @announce-*

To get more information on what Aruba is doing, use these tags:

  • @announce-cmd - See what command is is run
  • @announce-stdout - See the stdout
  • @announce-stderr - See the stderr
  • @announce-dir - See the current directory
  • @announce-env - See environment variables set by Aruba
  • @announce - Does all of the above

Keep files around with @no-clobber

Aruba clobbers all files in its working directory before each scenario. -Unless you tag it with @no-clobber

Making assertions about ANSI escapes with @ansi

Aruba strips away ANSI escapes from the stdout and stderr of spawned child processes by default. It's usually rather cumbersome to make assertions about coloured output. Still, there might be cases where you want to leave the ANSI escapes intact. Just tag your scenario with @ansi. Alternatively you can add your own Before hook that sets @aruba_keep_ansi = true.


Important - you need Pygments installed to use this feature.

Aruba can generate a HTML page for each scenario that contains:

  • The title of the scenario
  • The description from the scenario (You can use Markdown here)
  • The command(s) that were run
  • The output from those commands (in colour if the output uses ANSI escapes)
  • The files that were created (syntax highlighted in in colour)

In addition to this, it creates an index.html file with links to all individual report files. Reporting is off by default, but you can enable it by defining the ARUBA_REPORT_DIR environment variable, giving it the value where reports should be written:

ARUBA_REPORT_DIR=doc cucumber features

This will use Aruba's built-in template by default (See the templates folder). If you want to use your own template you can override its location:

ARUBA_REPORT_TEMPLATES=templates ARUBA_REPORT_DIR=doc cucumber features

The templates directory must contain a main.erb and files.erb template. It can also contain other assets such as css, javascript and images. All of these files will be copied over to the report dir well.

Escaping Markdown

There are some edge cases where Gherkin and Markdown don't agree. Bullet lists using * is one example. The * is also an alias for step keywords in Gherkin. Markdown headers (the kind starting with a #) is another example. They are parsed as comments by Gherkin. To use either of these, just escape them with a backslash. So instead of writing:

Scenario: Make tea
  ## Making tea
  * Get a pot
  * And some hot water

You'd write:

Scenario: Make tea
  \## Making tea
  \* Get a pot
  \* And some hot water


This way Gherkin won't recognize these lines as special tokens, and the reporter will render them as Markdown. (The reporter strips away any leading the backslashes before handing it off to the Markdown parser).

Another option is to use alternative Markdown syntax and omit conflicts and escaping altogether:

Scenario: Make tea
  Making tea
  - Get a pot
  - And some hot water


Note on Patches/Pull Requests

  • Fork the project.
  • Make your feature addition or bug fix.
  • Add tests for it. This is important so I don't break it in a future version unintentionally. Note: the existing tests may fail
  • Commit, do not mess with Rakefile, gemspec or History. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
  • Send me a pull request. Bonus points for topic branches.


Copyright (c) 2010,2011 Aslak Hellesøy, David Chelimsky and Mike Sassak. See LICENSE for details.