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End-to-end Testing in Mattermost

This page describes how to run End-to-End (E2E) testing and to build tests for a section or page of the Mattermost web application. Under the hood, we are using Cypress which is “fast, easy and reliable testing for anything that runs in a browser.”

Not familiar with Cypress? Here is some documentation that will help you get started:

Quick Overview on How to Run E2E Testing 

On Your Local Development Machine 

  1. Launch a local Mattermost instance by running make run in the mattermost-server directory. Confirm that the Mattermost instance has started successfully.
    • Run make test-data to preload your server instance with initial seed data.
    • Each test case should handle the required system or user settings, but in case you encounter an unexpected error while testing, you may want to run the server with default config based on mattermost-server/config/default.json.
    • In another terminal, in the mattermost-webapp directory, run npm run storybook. This is required for the Cypress tests which run against the Storybook widgets to pass.
  2. Change directory to mattermost-webapp/e2e, and install npm dependencies by running npm i.
    • Initiate npm run cypress:run in the command line to start full E2E testing. This excludes the specs in the /cypress/integration/enterprise folder as they require an Enterprise license to run successfully.
    • Initiate npm run cypress:open in the command line to start partial testing depending on which spec is selected via Cypress’s desktop app.
    • Initiate via node CLI to selectively run specs based on test metadata, e.g. node run_tests.js --group='@accessibility' which will run all specs with @accessibility metadata.
  3. Tests are executed according to your selection and will display whether the tests passed or failed.

Environment Variables 

We use several environment variables for Cypress testing in order to:

  • Easily change when running in CI.
  • Cater to different values across developer machines.

Environment variables are defined in cypress.json under the env key. In most cases you don’t need to change the values, because it makes use of the default local developer setup. If you do need to make changes, the easiest method is to override by exporting CYPRESS_*, where * is the key of the variable, for example: CYPRESS_adminUsername. See Cypress documentation for details.

Variable Description
CYPRESS_adminUsername Admin’s username for the test server.

Default: sysadmin when server is seeded by make test-data.
CYPRESS_adminPassword Admin’s password for the test server.

Default: Sys@dmin-sample1 when server is seeded by make test-data.
CYPRESS_dbClient The database of the test server. It should match the server config SqlSettings.DriverName.

Default: postgres
Valid values: postgres or mysql
CYPRESS_dbConnection The database connection string of the test server. It should match the server config SqlSettings.DataSource.

Default: "postgres://mmuser:mostest@localhost/mattermost_test?sslmode=disable\u0026connect_timeout=10"
CYPRESS_enableVisualTest Use for visual regression testing.

Default: false
Valid values: true or false
CYPRESS_ldapServer Host of LDAP server.

Default: localhost
CYPRESS_ldapPort Port of LDAP server.

Default: 389
CYPRESS_runLDAPSync Option to run LDAP sync.

Default: true
Valid values: true or false
CYPRESS_resetBeforeTest When set to true, it deletes all teams and their channels where sysadmin is a member except eligendi team and its channels.

Default: false
Valid values: true or false
CYPRESS_storybookUrl Host for common components or widget testing.

Default: http://localhost:6006/ when initiated npm run storybook from the root folder.
CYPRESS_webhookBaseUrl A server used for testing webhook integration.

Default: http://localhost:3000 when initiated npm run start:webhook.

In Continuous Integration Pipeline 

We run all tests in our Continuous Integration (CI) pipeline. However, they are grouped according to test stability.

  1. Daily production tests against development branch (master) - Initiated on master branch by node run_tests.js --stage='@prod' in the command line. These are tests, known as production tests, which were selected and labeled with @prod test metadata. See link for an example test run posted in our community channel.
  2. Daily production tests against release branch - Same as above except the test is initiated against the release branch. See link for an example test run.
  3. Daily unstable tests against development branch (master) - Initiated on the master branch by node run_tests.js --stage='@prod' --invert in the command line to run all except production tests. We call these unstable tests as they either consistently or intermittently fail due to automation bugs and not product bugs.

Folder and File Structures 

The folder structure is mostly based on the Cypress scaffold which was created on initial run. Folders and files are:

|-- e2e
  |-- cypress
    |-- fixtures
    |-- integration
    |-- plugins
    |-- support
    |-- utils
  |-- cypress.json
  |-- package-lock.json
  |-- package.json
  1. /e2e/cypress/fixtures or Fixture Files:
    • Fixtures are used as external pieces of static data that can be used by tests.
    • Typically used with the cy.fixture() command and most often when stubbing Network Requests.
  2. /e2e/cypress/integration or Test Files
    • To start writing tests,
      • simply create a new file (e.g. login_spec.js) within /e2e/cypress/integration folder and;
      • refresh tests list in the Cypress Test Runner and a new file should have appeared in the list.
    • Subfolder naming convention depends on test grouping, which is usually based on the general functional area (e.g. /e2e/cypress/integration/messaging/ for “Messaging”).
    • Test cases that require an enterprise license should fall under /e2e/cypress/integration/enterprise/. This is to easily identify license requirements, both during local development and production testing for enterprise features.
  3. /e2e/cypress/plugins or Plugin Files
    • A convenience mechanism that automatically include the plugins before running every single spec file.
  4. /e2e/cypress/support or Support Files
    • The support file is a place to put reusable behaviour such as Custom Commands or global overrides that are wished to be applied and available to all of spec files.
  5. /e2e/cypress/utils for common utility functions.
  6. /e2e/cypress.json for Cypress configuration.
  7. /e2e/package.json for all dependencies related to Cypress end-to-end testing.

What requires an E2E Test? 

  1. Test cases defined in help-wanted E2E issues - see link which opens a private channel using keyboard navigation with Ctrl/Cmd+K, arrow and enter keys.
  2. New features or stories - see link for Mark As Unread feature.
  3. Bug fixes - see link that fixes mention highlight to self.
  4. Test cases from TM4J - see link which adds automated tests for Guest Accounts.

Interested in Contributing to E2E Testing through Help Wanted Tickets 

  1. All help wanted tickets are under server repository’s GitHub issues. Look for issues with Area/E2E Tests and Up For Grabs labels, and comment to let everyone know you’re working on it.
  2. Each ticket is filled up with specific test steps and verifications that need to be accomplished as a minimum requirement. Additional steps and assertions for robust test implementation are much welcome.
  3. Join our channel at UI Test Automation and talk to us as fellow contributors, and collaborate and learn with one another.

Guide for Writing E2E Testing 

Where should the new test go? 

Inside e2e/cypress/integration is where all of the tests live. Cypress is configured to look for and run tests that match the pattern of *_spec.js, so if you are creating a new test make sure to name it something like my_new_test_spec.js to ensure that it gets picked up.

Inside of the integration directory, there are additional directories that break up the tests roughly by functional areas. If you see something that looks like it describes the functional area of your test, it should probably live inside that directory. From there, look to see if there is already a *_spec.js file that may be similar to what you are testing, it can be very likely that you can add additional tests to a pre-existing file.

Writing Specs 

  1. The recommended practice of Cypress is to use data-* attribute to provide context to selectors, but we prefer to use element ID instead.

    • If element ID is not present in the webapp, you may add it in camelCase form with human readable name (e.g. <div id='sidebarTitle'>). Watch out for potential breaking changes in the snapshot of the unit testing. Run make test to see if all are passing, and run npm run updatesnapshot or npm run test -- -u if necessary to update snapshot testing.
  2. Add custom commands to /e2e/cypress/support. See Cypress documentation for more details about custom commands [link].

    • For ease of use, in-code documentation and discoverability, custom commands should have type definition added. See declaration file for reference on how to include.
  3. Organize /e2e/cypress/integration with a subfolder to group similar tests.

  4. Each test should have a corresponding test case in Test Management for Jira (TM4J). Therefore, the describe block should correspond to folder name in TM4J (e.g. “Incoming webhook”), and it block should contain TM4J number as Test Key and test title (e.g. “MM-T623 Lock to this channel on webhook configuration works”). In the spec file, it should be written as:

    describe('Incoming webhook', () => {
        it('MM-T623 Lock to this channel on webhook configuration works', () => {
            // Test steps and assertion here

    For those writing E2E from help-wanted tickets with Area/E2E Tests label, the Test Key is available in the GitHub issue itself.

    Test Key is used for mapping test cases per Release Testing specification. It will be used to measure coverage between manual and automated tests.

    In case the Test Key is not available, feel free to prompt the QA team who will either search from an existing TM4J entry or if it’s a new one, it will be created for you.

  5. Add check if a certain test requires server license.

    describe('Test description', () => {
       before(() => {
           // If the test requires a certain licensed feature
           // If server has license in general
  6. Run test in isolation using a convenient custom command of cy.apiInitSetup(). This command creates a new team, channel, and user which can be used by the spec file itself only.

  7. Refer to this pull request as a guide on how to write and submit an end-to-end testing PR.

Adding Test Metadata on Spec Files 

Test metadata is used to identify each spec file ahead of time before it is forwarded for Cypress run. Currently, supported test metadata are the following:

  1. “Stage” - indicates environment for testing, e.g. @prod, @smoke, @pull_request. “Stage” metadata is owned and controlled by QA team who carefully analyze stability of test and promote/demote into a certain stage. This is not required when submitting a spec file.
  2. “Group” - indicates test group or category, which is primarily based on functional areas and existing release testing groups, e.g. @account_settings for Account Settings, @messaging for Messaging, etc. This is required when submitting a spec file.
  3. “Skip” - is a way to skip a spec file depending on capability of test environment. This is required when submitting a spec file if a test has certain limitation or requirement. Capabilities could be as follows:
    • Per platform, e.g. @darwin for Mac, @linux for Linux flavor like Ubuntu, @win32 for Windows, etc.
    • Per browser, e.g. @electron, @chrome, @firefox, @edge
    • Per headless or headed, e.g. @headless or @headed

A spec file can have zero or more metadata separated by space.

// Stage: @prod @smoke
// Group: @enterprise @saml
// Skip:  @headless @electron @firefox


Cypress Failed To Start After Running ‘npm run cypress:run’ 

Either the command line exits immediately without running any test or it logs out like the following.

Error message 
✖  Verifying Cypress can run /Users/user/Library/Caches/Cypress/3.1.3/
   → Cypress Version: 3.1.3
Cypress failed to start.

This is usually caused by a missing library or dependency.

Clear node options by initiating unset NODE_OPTIONS in the command line. Running npm run cypress:run should proceed with Cypress testing.

Error message 

This error may occur in Ubuntu when running any Cypress spec.

code: 'ENOSPC',
errno: 'ENOSPC',

Run the following command

echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p