mattermost/server/tests/README.md

# Testing Text Processing  
The text processing tests located in the [doc/developer/tests folder](https://github.com/mattermost/platform/tree/master/doc/developer/tests) are designed for use with the `/test url` command in isolated non-production test environments. This command posts the raw contents of a specified `.md` file in the `doc/developer/tests` folder into Mattermost.

## Turning on /test  
Access the **System Console** from the Main Menu. Under *Environment > Developer* make sure that *Enable Testing Commands* is set to `true`, then click **Save**. You may also change this setting from `config.json` by setting `"EnableTesting": true`. This setting is intended only for isolated non-production environments with test users and sample data, and must never be enabled in production. Changing this setting requires a server restart to take effect.

## Running the Tests  
In the text input box in Mattermost, type: `/test url [file-name-in-testing-folder].md`. Some examples:

`/test url test-emoticons.md`  
`/test url test-links.md`

#### Notes:    
1. If a test has prerequisites, make sure your Mattermost setup meets the requirements described at the top of the test file.
2. Some tests are over 4000 characters in length and will render across multiple posts.

## Manual Testing  
It is possible to manually test specific sections of any test, instead of using the /test command. Do this by clicking **Raw** in the header for the file when it’s open in GitHub, then copy and paste any section into Mattermost to post it. Manual testing only supports sections of 4000 characters or less per post.

## Test plugins

There are three test plugins: `testplugin.tar.gz`, `testplugin-v0.0.2.tar.gz`, and `testplugin2.tar.gz`. These are use in some integration tests in the `api4` package. Any changes to the plugin bundles require updating the corresponding signatures.

First, import the public and private development key:
```sh
gpg --import ./development-public-key.gpg
gpg --import ./development-private-key.asc
```

This has to be done only once.

Then update the signatures:
```sh
gpg -u F3FACE45E0DE642C8BD6A8E64C7C6562C192CC1F --verbose --personal-digest-preferences SHA256 --detach-sign testplugin.tar.gz
gpg -u F3FACE45E0DE642C8BD6A8E64C7C6562C192CC1F --verbose --personal-digest-preferences SHA256 --detach-sign --armor testplugin.tar.gz
gpg -u F3FACE45E0DE642C8BD6A8E64C7C6562C192CC1F --verbose --personal-digest-preferences SHA256 --detach-sign testplugin-v0.0.2.tar.gz
gpg -u F3FACE45E0DE642C8BD6A8E64C7C6562C192CC1F --verbose --personal-digest-preferences SHA256 --detach-sign --armor testplugin-v0.0.2.tar.gz
gpg -u F3FACE45E0DE642C8BD6A8E64C7C6562C192CC1F --verbose --personal-digest-preferences SHA256 --detach-sign testplugin2.tar.gz
gpg -u F3FACE45E0DE642C8BD6A8E64C7C6562C192CC1F --verbose --personal-digest-preferences SHA256 --detach-sign --armor testplugin2.tar.gz
```

Finally, include the updates bundles and signatures in your commit.

## Image fixtures

The `api4` package tests compare server-generated image thumbnails and previews against fixture files (e.g. `orientation_test_1_expected_thumb.jpeg`). Comparisons are pixel-based with a small tolerance, so minor encoder drift across patch releases is handled automatically.

However, Go's `image/jpeg` encoder has changed incompatibly across major versions (e.g. Go 1.25 → 1.26). When upgrading Go, regenerate the JPEG fixtures by running:

```sh
go test -run "TestUploadFiles/.*thumbnail" ./channels/api4/ -args -update-fixtures
go test -run "TestGenerateMiniPreviewImage" ./channels/app/imaging/ -args -update-fixtures
```

Run both from `server/`. Commit the updated fixture files alongside the Go version bump.