Cool Cucumber
Run Cucumber tests from feature files with Jest.
Idea
You want to write wonderful feature files (in Gherkin), but instead of using Cucumber's runner you want to get all the nice feature from Jest that you get for free with create-react-app or even create-next-app.
Implementation
Jest can use custom transforms to read files it cannot parse on its own. This library is a custom transform for .feature files.
As it uses official cucumber libraries, it should be able to parse pretty much all valid feature files. Here is a probably outdated list of things it generates:
Features becomedescribeblocksExamples/Scenarios becometestblocksGiven,When,Then,And,*,Butis supported of courseScenario Outlines are instantiated for all their examples astestblocks as well- If a
Backgroundis present, it is include in all the affected scenarios - Data Tables are supported
- Expressions are supported
@skiptag will (you guessed it) skip the feature/scenario
Not implement/tested:
- Before/After hooks are not supported yet
- Custom tags are included as (invisible) comments only for now
- Doc Strings have not been tested
Rules have not been tested
Usage
Add this library as a dependency. Also add @cucumber/cucumber and @cucumber/messages which are needed at runtime.
Config
You'll need to extend your jest.config.js:
- Add the file(s) that have your step definitions to
setupFilesAfterEnv - Add
featureto themoduleFileExtensions - Add
"\\.feature$": 'cool-cucumber',totransform - Add something like
"<rootDir>/features/*.feature",totestMatch
You can find an example based on Next.js' jest config in example-nextjs/jest.config.js.
Step definition
You define your steps as usual for Cucumber, but at the very beginning you'll need to add this:
import { default as supportCodeLibraryBuilder } from "@cucumber/cucumber/lib/support_code_library_builder";
import { uuid } from "@cucumber/messages/dist/src/IdGenerator";
supportCodeLibraryBuilder.reset(process.cwd(), uuid());
This is for some reason the only stable way to initialize Cucumber so that it can find all steps and refer to them later on in the generated code.
Inspiration
This library is inspired by cucumber-jest, which solves this problem in a very similar way. cucumber-jest is written by Dayne Mentier and licensed under the MIT license.
The reasons I have not used/extended this instead is that it seems to run each step in a Jest test block, which breaks jsdom or at least makes it less convenient to use. It also created the Jest tests at runtime. You can see this library here as an experimental alternative implementation. I have not copied any of its code, and only used it as inspiration/reference.
License
Licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
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