Remove Cypress & Playwright in their entirety (#12145)
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# Testing
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- [Cypress end to end](cypress.md)
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- [Playwright end to end](playwright.md)
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docs/cypress.md
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docs/cypress.md
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# Cypress in Element Web
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# 🚨 We are moving away from Cypress in favour of Playwright.
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Please do not write any new tests in Cypress and check out [the Playwright docs](playwright.md).
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## Contents
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- How to run the tests
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- How the tests work
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- How to write great Cypress tests
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- Visual testing
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## Running the Tests
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Our Cypress tests run automatically as part of our CI along with our other tests,
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on every pull request and on every merge to develop & master.
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However the Cypress tests are run, an element-web must be running on
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http://localhost:8080 (this is configured in `cypress.json`) - this is what will
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be tested. When running Cypress tests yourself, the standard `yarn start` from the
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element-web project is fine: leave it running it a different terminal as you would
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when developing.
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The tests use Docker to launch Homeserver (Synapse or Dendrite) instances to test against, so you'll also
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need to have Docker installed and working in order to run the Cypress tests.
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There are a few different ways to run the tests yourself. The simplest is to run:
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```
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docker pull matrixdotorg/synapse:develop
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yarn run test:cypress
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```
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This will run the Cypress tests once, non-interactively.
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Note: you don't need to run the `docker pull` command every time, but you should
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do it regularly to ensure you are running against an up-to-date Synapse.
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You can also run individual tests this way too, as you'd expect:
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```
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yarn run test:cypress --spec cypress/e2e/1-register/register.spec.ts
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```
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Cypress also has its own UI that you can use to run and debug the tests.
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To launch it:
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```
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yarn run test:cypress:open
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```
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### Matching the CI environment
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In our Continuous Integration environment, we run the Cypress tests in the
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Chrome browser, and with the latest Synapse image from Docker Hub.
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In some rare cases, tests behave differently between different browsers, so if
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you see CI failures for the Cypress tests, but those tests work OK on your local
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machine, try running them in Chrome like this:
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```bash
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yarn run test:cypress --browser=chrome
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```
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(Use `--browser=chromium` if you'd prefer to use Chromium.)
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If you launch the interactive UI you can choose the browser you want to use. To
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match the CI setup, choose Chrome.
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Note that you will need to have Chrome installed on your system to run the tests
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inside those browsers, whereas the default is to use Electron, which is included
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within the Cypress dependency.
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Another cause of inconsistency between local and CI is the Synapse version. The
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first time you run the tests, they automatically fetch the latest Docker image
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of Synapse, but this won't update again unless you do it explicitly. To update
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the Synapse you are using, run:
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```
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docker pull matrixdotorg/synapse:develop
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```
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and then run the tests as normal.
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### Running with Rust cryptography
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`matrix-js-sdk` is currently in the
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[process](https://github.com/vector-im/element-web/issues/21972) of being
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updated to replace its end-to-end encryption implementation to use the [Matrix
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Rust SDK](https://github.com/matrix-org/matrix-rust-sdk). This is not currently
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enabled by default, but it is possible to have Cypress configure Element to use
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the Rust crypto implementation by setting the environment variable
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`CYPRESS_RUST_CRYPTO=1`.
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## How the Tests Work
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Everything Cypress-related lives in the `cypress/` subdirectory of react-sdk
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as is typical for Cypress tests. Likewise, tests live in `cypress/e2e`.
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`cypress/plugins/synapsedocker` contains a Cypress plugin that starts instances
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of Synapse in Docker containers. These synapses are what Element-web runs against
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in the Cypress tests.
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Synapse can be launched with different configurations in order to test element
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in different configurations. `cypress/plugins/synapsedocker/templates` contains
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template configuration files for each different configuration.
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Each test suite can then launch whatever Synapse instances it needs in whatever
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configurations.
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Note that although tests should stop the Homeserver instances after running and the
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plugin also stop any remaining instances after all tests have run, it is possible
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to be left with some stray containers if, for example, you terminate a test such
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that the `after()` does not run and also exit Cypress uncleanly. All the containers
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it starts are prefixed, so they are easy to recognise. They can be removed safely.
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After each test run, logs from the Synapse instances are saved in `cypress/synapselogs`
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with each instance in a separate directory named after its ID. These logs are removed
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at the start of each test run.
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## Writing Tests
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Mostly this is the same advice as for writing any other Cypress test: the Cypress
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docs are well worth a read if you're not already familiar with Cypress testing, eg.
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https://docs.cypress.io/guides/references/best-practices. To avoid your tests being
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flaky it is also recommended to give https://docs.cypress.io/guides/core-concepts/retry-ability
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a read.
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### Getting a Synapse
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The key difference is in starting Synapse instances. Tests use this plugin via
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`cy.startHomeserver()` to provide a Homeserver instance to log into:
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```javascript
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cy.startHomeserver("consent").then((result) => {
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homeserver = result;
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});
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```
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This returns an object with information about the Homeserver instance, including what port
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it was started on and the ID that needs to be passed to shut it down again. It also
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returns the registration shared secret (`registrationSecret`) that can be used to
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register users via the REST API. The Homeserver has been ensured ready to go by awaiting
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its internal health-check.
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Homeserver instances should be reasonably cheap to start (you may see the first one take a
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while as it pulls the Docker image), so it's generally expected that tests will start a
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Homeserver instance for each test suite, i.e. in `before()`, and then tear it down in `after()`.
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To later destroy your Homeserver you should call `stopHomeserver`, passing the HomeserverInstance
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object you received when starting it.
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```javascript
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cy.stopHomeserver(homeserver);
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```
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### Synapse Config Templates
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When a Synapse instance is started, it's given a config generated from one of the config
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templates in `cypress/plugins/synapsedocker/templates`. There are a couple of special files
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in these templates:
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- `homeserver.yaml`:
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Template substitution happens in this file. Template variables are:
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- `REGISTRATION_SECRET`: The secret used to register users via the REST API.
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- `MACAROON_SECRET_KEY`: Generated each time for security
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- `FORM_SECRET`: Generated each time for security
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- `PUBLIC_BASEURL`: The localhost url + port combination the synapse is accessible at
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- `localhost.signing.key`: A signing key is auto-generated and saved to this file.
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Config templates should not contain a signing key and instead assume that one will exist
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in this file.
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All other files in the template are copied recursively to `/data/`, so the file `foo.html`
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in a template can be referenced in the config as `/data/foo.html`.
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### Logging In
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There exists a basic utility to start the app with a random user already logged in:
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```javascript
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cy.initTestUser(homeserver, "Jeff");
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```
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It takes the HomeserverInstance you received from `startHomeserver` and a display name for your test user.
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This custom command will register a random userId using the registrationSecret with a random password
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and the given display name. The returned Chainable will contain details about the credentials for if
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they are needed for User-Interactive Auth or similar but localStorage will already be seeded with them
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and the app loaded (path `/`).
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The internals of how this custom command run may be swapped out later,
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but the signature can be maintained for simpler maintenance.
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### Joining a Room
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Many tests will also want to start with the client in a room, ready to send & receive messages. Best
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way to do this may be to get an access token for the user and use this to create a room with the REST
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API before logging the user in. You can make use of `cy.getBot(homeserver)` and `cy.getClient()` to do this.
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### Convenience APIs
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We should probably end up with convenience APIs that wrap the homeserver creation, logging in and room
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creation that can be called to set up tests.
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### Try to write tests from the users's perspective
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Like for instance a user will not look for a button by querying a CSS selector. Instead you should work
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with roles / labels etc.. You can make use of `cy.findBy…` queries provided by
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[Cypress Testing Library](https://github.com/testing-library/cypress-testing-library).
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### Using matrix-js-sdk
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Due to the way we run the Cypress tests in CI, at this time you can only use the matrix-js-sdk module
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exposed on `window.matrixcs`. This has the limitation that it is only accessible with the app loaded.
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This may be revisited in the future.
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## Good Test Hygiene
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This section mostly summarises general good Cypress testing practice, and should not be news to anyone
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already familiar with Cypress.
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1. Test a well-isolated unit of functionality. The more specific, the easier it will be to tell what's
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wrong when they fail.
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1. Don't depend on state from other tests: any given test should be able to run in isolation.
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1. Try to avoid driving the UI for anything other than the UI you're trying to test. e.g. if you're
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testing that the user can send a reaction to a message, it's best to send a message using a REST
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API, then react to it using the UI, rather than using the element-web UI to send the message.
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1. Avoid explicit waits. `cy.get()` will implicitly wait for the specified element to appear and
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all assertions are retired until they either pass or time out, so you should never need to
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manually wait for an element.
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- For example, for asserting about editing an already-edited message, you can't wait for the
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'edited' element to appear as there was already one there, but you can assert that the body
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of the message is what is should be after the second edit and this assertion will pass once
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it becomes true. You can then assert that the 'edited' element is still in the DOM.
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- You can also wait for other things like network requests in the
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browser to complete (https://docs.cypress.io/guides/guides/network-requests#Waiting).
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Needing to wait for things can also be because of race conditions in the app itself, which ideally
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shouldn't be there!
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This is a small selection - the Cypress best practices guide, linked above, has more good advice, and we
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should generally try to adhere to them.
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## Screenshot testing with Percy
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**⚠️ Percy is disabled while we're figuring out https://github.com/vector-im/wat-internal/issues/36**
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**and https://github.com/vector-im/wat-internal/issues/56. We're hoping to turn it back on or switch**
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**to an alternative in the future.**
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We also support visual testing via [Percy](https://percy.io). Within many of our
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Cypress tests you can see lines calling `cy.percySnapshot()`. This creates a
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screenshot and uses Percy to check whether it has changed from the last time
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this test was run.
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It can help to pass `percyCSS` in as the 2nd argument to `percySnapshot` to hide
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elements that vary (e.g. timestamps). See the existing code for examples of
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this. (Note: it is also possible for team members to mark certain parts of a
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screenshot to be ignored. This is done within the Percy UI.)
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Percy screenshots are created using custom renderers based on Safari, Firefox,
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Chrome and Edge. Each `percySnapshot` actually creates 8 screenshots (4
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browsers, 2 sizes). Since we have a limited budget for Percy screenshots, by
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default we only run Percy once per day against the `develop` branch, based on a
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nightly build at approximately 04:00 UTC every day. (The schedule is defined in
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[element-web.yaml](../.github/workflows/element-web.yaml) and the Percy tests are
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enabled/disabled in [cypress.yaml](../.github/workflows/cypress.yaml).)
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If your pull request makes visual changes, you are encouraged to request Percy
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to run by adding the label `X-Needs-Percy` to the PR, these will only run in
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the merge queue to save snapshots. This will help us find any
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visual bugs or validate visual changes at the time they are made, instead of
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having to figure it out later after the nightly build. If you don't have
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permission to add a label, please ask your reviewer to do it. Note: it's best to
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add this label when the change is nearly ready, because the screenshots will be
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re-created every time you make a change to your PR.
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Some UI elements render differently between test runs, such as BaseAvatar when
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there is no avatar set, choosing a colour from the theme palette based on the
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hash of the user/room's Matrix ID. To avoid this creating flaky tests we can use
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the `@media only percy` CSS query to override the variable colour into a fixed one
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for tests where it is not feasible to fix the underlying identifiers issued by the
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server. See https://docs.percy.io/docs/percy-specific-css#percy-css-media-query.
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