Len edited this page Sep 2, 2016 · 32 revisions

Tags are a great way to organise your features and scenarios. Consider this example:

Feature: Verify billing

  Scenario: Missing product description

  Scenario: Several products

A Scenario or feature can have as many tags as you like. Just separate them with spaces:

@billing @bicker @annoy
Feature: Verify billing

Tag Inheritance

Any tag that exists on a Feature will be inherited by Scenario, Scenario Outline or Examples.

Running a subset of scenarios

You can use the --tags option to tell Cucumber that you only want to run features or scenarios that have (or don’t have) certain tags. Examples:

cucumber --tags @billing            # Runs both scenarios
cucumber --tags @important          # Runs the first scenario
cucumber --tags ~@important         # Runs the second scenario (Scenarios without @important)

cucumber --tags @billing --tags @important    # Runs the first scenario (Scenarios with @important AND @billing)
cucumber --tags @billing,@important           # Runs both scenarios (Scenarios with @important OR @billing)

(Another way to “filter” what you want to run is to use the file.feature:line pattern or the --scenario option as described in Running Features).

Tags are also a great way to “link” your Cucumber features to other documents. For example, if you have to deal with old school requirements in a different system (Word, Excel, a wiki) you can refer to numbers:

@BJ-x98.77 @BJ-z12.33
Feature: Convert transaction

Another creative way to use tags is to keep track of where in the development process a certain feature is:

Feature: Index projects

Tags are also used in Tagged Hooks, which let you use tags to define what Before and After blocks get run for what scenarios.

Logically ANDing and ORing Tags

As you may have seen in the previous examples Cucumber allows you to use logical ANDs and ORs to help gain greater control of what features to run.

Tags which are comma separated are ORed:

Example: Running scenarios which match @important OR @billing

cucumber --tags @billing,@important

Tags which are passed in separate —tags are ANDed

Example: Running scenarios which match @important AND @billing

cucumber --tags @billing --tags @important

You can combine these two methods to create powerful selection criteria:

Example: Running scenarios which match: (@billing OR @WIP) AND @important

cucumber --tags @billing,@wip --tags @important

Example: Skipping both @todo and @wip tags

cucumber --tags ~@todo --tags ~@wip

You can use this tag logic in your Hooks as well.

This feature was originally added in version 0.4.3. The logical behaviour of tags was later reversed in version 0.6.0.

Overriding the tag filters from a profile

It is currently not possible to override the tag filters from a profile.

The default profile, for example, includes a --tags ~@wip filter. But what if you want to use everything from the default profile except the `—tags ~@wip` portion?

You might think you could just append something like this to the command line to “undo” the --tags from the profile: --tags @wip,~@wip (anything either tagged with @wip or not tagged with @wip)

But because that is effectively doing an “and” between --tags ~@wip and --tags @wip,~@wip, it doesn’t match any scenarios.

How can we override the tag filter then?

Tag limits and WIP

If you’re following Kanban principles, you want to limit the work in progress (WIP). The idea is that the fewer features or scenarios that being worked on simultaneously, the quicker you’ll be able to implement new features.

Cucumber can enforce this using tag limits. Here is an example:

cucumber --tags @dev:2,@qa:3

This will make cucumber fail if you have more than 2 @dev tags or more than 3 @qa tags, even if each of your scenarios pass individually.

Used in conjunction with the --wip switch you can set up your project to enforce the WIP limits of your team.

Special Tags

@allow-rescue: Turns off Cucumber’s exception capturing for the tagged scenario(s). Used when the code being tested is expected to raise and handle exceptions.

@javascript: Uses a javascript-aware system to process web requests (e.g., Selenium) instead of the default (non-javascript-aware) webrat browser.

@no-txn: Turns off transactions. See Browsers and Transactions.