Contributing Guide

Contributions are welcome and are greatly appreciated! Every little bit helps, and credit will always be given.

Setting up your environment

After forking enzyme to your own github org, do the following steps to get started:

# clone your fork to your local machine
git clone

# step into local repo
cd enzyme

# install dependencies (use `react 13` if you want to use React 0.13)
npm install

# install react version
# accepts `13` for v0.13, `14` for v0.14, and for versions 15+,
# accepts either a major (`15`, `16`) or a minor (`15.4`, `16.8`)
npm run react 16

Switching between React 16, React 15, React 0.14 and React 0.13

# switch to React 0.13
npm run react 13
# switch to React 0.14
npm run react 14
# switch to React 15
npm run react 15
# switch to React 16
npm run react 16

Specific versions can also be specified

# switch to React 16.5
npm run react 16.5

Running Tests

The test suite runs on built Enzyme.

# build Enzyme locally before testing
npm run build

# run tests on whatever version of React is currently installed
npm test
# run tests on all supported versions of React
npm run test:all

If you are actively developing, Enzyme will always need to be built with the latest changes.

For this, the recommended workflow is to have the build and tests watching for changes in separate terminals. This should provide you with ~realtime feedback:

# build Enzyme locally upon save
npm run build:watch

# faster feedback for TDD
npm run test:watch

Tests for functionality shared between shallow and mount

Tests for a method "foo" are stored in packages/enzyme-test-suite/test/shared/methods/foo. The file default exports a function that receives an injected object argument, containing the following properties:

  • Wrap: e.g. shallow, mount
  • WrapRendered: this abstracts around the differences between shallow and mount - e.g., that the root of a shallow wrapper around Foo is what Foo renders, where the root of a mount wrapper around Foo is Foo itself. Thus, this function produces a wrapper around what Foo renders, regardless of the Wrap method used.
  • Wrapper: e.g. ShallowWrapper, ReactWrapper
  • WrapperName: e.g. "ShallowWrapper", "ReactWrapper"
  • isShallow: true if shallow. note: needing to use this is a code smell, please avoid.
  • isMount: true if mount. note: needing to use this is a code smell, please avoid.
  • makeDOMElement: in mount, makes a real DOM element; in shallow, makes a mock object.

    These tests are ran via an explicit list in a describeMethods call in the ReactWrapper and ShallowWrapper test files. If you add a new test file for a shared method, you'll need to add its name to both calls.

Style & Linting

This codebase adheres to the Airbnb Styleguide and is enforced using ESLint.

As with the test suite, the linter will not fully pass unless it is running on built Enzyme. This is because the ESLint import/* rules rely on finding the target files in the filesystem (which won't be there unless they've been built).

It is recommended that you install an ESLint plugin for your editor of choice when working on this codebase, however you can always check to see if the source code is compliant by running:

# build Enzyme locally before linting
npm run build

npm run lint


Enzyme uses lerna to structure its repo, and has multiple packages to publish out of this one repo. We use lerna's "independent" mode, which means that the versioning of each package in the repo is versioned independently.

We are waiting on this issue to be fixed, so that peerDependencies do not get updated with patch updates.

Until this issue is fixed, we will publish each package manually instead of with lerna publish. In order to do this, we will:

For enzyme:

# ... update version in enzyme/package.json, make changes to CHANGELOG, etc.
cd packages/enzyme
git commit -m v{version}
git tag -a -m v{version}
git push --follow-tags
npm publish

For other packages

# ... update version in {package}/package.json, make changes to CHANGELOG, etc.
cd packages/{package}
git commit -m "{package}: v{version}"
git tag -a -m "{package}: v{version}"
git push --follow-tags
npm publish

Once we are able to use lerna publish, the process will be as follows:

Lerna by default will only publish packages that have changed since the last release. It will also create a tagged commit for each release.

To publish, run:

lerna publish -m "{tag name}"

The tag name is determined by the -m CLI option. If enzyme is one of the packages that has updates, we default to just using that version as the tag name. For instance, when publishing enzyme@3.1.1 and enzyme-adapter-react-16@1.2.3 we would run:

lerna publish -m "v3.1.1"

If enzyme is not one of the packages being updated, use the other package's name and the version:

lerna publish -m "enzyme-adapter-react-16: v1.2.3"

The lerna publish command will present interactive prompts asking which version to use for each package independently. Just choose whichever

Building Docs

Building the docs locally is extremely simple. First execute the following command:

npm run docs:watch

After this, you can open up your browser to the specified port (usually http://localhost:4000 )

The browser will automatically refresh when there are changes to any of the source files.

Pull Request Guidelines

Before you submit a pull request from your forked repo, check that it meets these guidelines:

  1. If the pull request fixes a bug, it should include tests that fail without the changes, and pass with them.
  2. If the pull request adds functionality, the docs should be updated as part of the same PR.
  3. The pull request should work for React 15, React 0.14 and React 0.13. The CI server should run the tests in all versions automatically when you push the PR, but if you'd like to check locally, you can do so (see above).
  4. Please rebase and resolve all conflicts before submitting.