5.2. Help about Cucumber

For C/C++, we use the tool cucumber, the ruby implementation for BDD.

To install it, follow the section Step - 00 : Installation of Cucumber for C/C++

To get help of cucumber command, run:

cucumber --help

Manually formatted

In general, almost every text in this book is shown verbatim, without any formatting/changes by the author. Which leads to a guarantee that what ever you see is latest/greatest and working as-is with 100% confidence.

The output from cucumber does not fit nicely into PDF format of the book, and hence it is manually re-formatted to be shown here.

This approach has a potential that eventually cucumber help may be more up-to-date and this section may get little bit stale.

Usage: cucumber [options] [ [FILE|DIR|URL][:LINE[:LINE]*] ]+


cucumber examples/i18n/en/features

cucumber @rerun.txt (See --format rerun)

cucumber examples/i18n/it/features/somma.feature:6:98:113

cucumber -s -i http://rubyurl.com/eeCl


-r, –require LIBRARY|DIR:

Require files before executing the features. If this option is not specified, all *.rb files that are siblings or below the features will be loaded auto-matically. Automatic loading is disabled when this option is specified, and all loading becomes explicit. Files under directories named support are always loaded first. This option can be specified multiple times.

–i18n LANG:

List keywords for in a particular language Run with “–i18n help” to see all languages

-f, –format FORMAT:

How to format features (Default: pretty).

Available formats:

  • debug

    For developing formatters - prints the calls made to the listeners.

  • html

    Generates a nice looking HTML report.

  • json

    Prints the feature as JSON

  • json_pretty

    Prints the feature as prettified JSON

  • junit

    Generates a report similar to Ant+JUnit.

  • pretty

    Prints the feature as is - in colours.

  • progress

    Prints one character per scenario.

  • rerun

    Prints failing files with line numbers.

  • stepdefs

    Prints All step definitions with their locations. Same as the usage formatter, except that steps are not printed.

  • usage

    Prints where step definitions are used. The slowest step definitions (with duration) are listed first.

    If --dry-run is used the duration is not shown, and step definitions are sorted by filename instead.

Use --format rerun --out rerun.txt to write out failing features. You can rerun them with cucumber @rerun.txt.

FORMAT can also be the fully qualified class name of your own custom formatter. If the class isn’t loaded, Cucumber will attempt to require a file with a relative file name that is the underscore name of the class name.

Example: --format Foo::BarZap. Cucumber will look for foo/bar_zap.rb. You can place the file with this relative path underneath your features/support directory or anywhere on Ruby’s LOAD_PATH, for example in a Ruby gem.


Initializes folder structure and generates conventional files for a Cucumber project.

-o, –out [FILE|DIR]:

Write output to a file/directory instead of STDOUT. This option applies to the previously specified –format, or the default format if no format is specified. Check the specific formatter’s docs to see whether to pass a file or a dir.


Only execute the features or scenarios with tags matching TAG_EXPRESSION. Scenarios inherit tags declared on the Feature level. The simplest TAG_EXPRESSION is simply a tag. Example: --tags @dev.

When a tag in a tag expression starts with a ~, this represents boolean NOT. Example: --tags ~@dev.

A tag expression can have several tags separated by a comma, which represents logical OR. Example: --tags @dev,@wip.

The –tags option can be specified several times, and this represents logical AND. Example: --tags @foo,~@bar --tags @zap. This represents the boolean expression (@foo || !@bar) && @zap.

Beware that if you want to use several negative tags to exclude several tags you have to use logical AND: --tags ~@fixme --tags ~@buggy.

Positive tags can be given a threshold to limit the number of occurrences. Example: --tags @qa:3 will fail if there are more than 3 occurrences of the @qa tag. This can be practical if you are practicing Kanban or CONWIP.

-n, –name NAME:

Only execute the feature elements which match part of the given name. If this option is given more than once, it will match against all the given names.

-e, –exclude PATTERN:

Don’t run feature files or require ruby files matching PATTERN

-p, –profile PROFILE:

Pull commandline arguments from cucumber.yml which can be defined as strings or arrays. When a ‘default’ profile is defined and no profile is specified it is always used. (Unless disabled, see -P below.) When feature files are defined in a profile and on the command line then only the ones from the command line are used.

-P, –no-profile:

Disables all profile loading to avoid using the ‘default’ profile.

-c, –[no-]color:

Whether or not to use ANSI color in the output. Cucumber decides based on your platform and the output destination if not specified.

-d, –dry-run:

Invokes formatters without executing the steps. This also omits the loading of your support/env.rb file if it exists.

-m, –no-multiline:

Don’t print multiline strings and tables under steps.

-s, –no-source:

Don’t print the file and line of the step definition with the steps.

-i, –no-snippets:

Don’t print snippets for pending steps.

-I, –snippet-type TYPE:

Use different snippet type (Default: regexp).

Available types:

  • classic

    Snippets without parentheses. Note that these cause a warning from modern versions of Ruby. e.g. Given /^missing step$/

  • percent

    Snippets with percent regexp e.g. Given %r{^missing step$}

  • regexp

    Snippets with parentheses e.g. Given(/^missing step$/)

-q, –quiet:

Alias for –no-snippets –no-source.

-b, –backtrace:

Show full backtrace for all errors.

-S, –strict:

Fail if there are any undefined or pending steps.

-w, –wip:

Fail if there are any passing scenarios.

-v, –verbose:

Show the files and features loaded.

-g, –guess:

Guess best match for Ambiguous steps.

-l, –lines LINES:

Run given line numbers. Equivalent to FILE:LINE syntax

-x, –expand:

Expand Scenario Outline Tables in output.

–order TYPE[:SEED]:

Run examples in the specified order. Available types:

  • defined

    Run scenarios in the order they were defined (default).

  • random

    Shuffle scenarios before running.

Specify SEED to reproduce the shuffling from a previous run. e.g. –order random:5738


Show version.

-h, –help:

You’re looking at it.

To learn more about cucumber, visit: