# Lexer tests The tests in this directory feed a known input `testdata/<name>.actual` into the parser for `<name>` and check that its output matches `<name>.exported`. ## Running the tests Run the tests as normal: ```go go test ./lexers ``` ## Update existing tests When you add a new test data file (`*.actual`), you need to regenerate all tests. That's how Chroma creates the `*.expected` test file based on the corresponding lexer. To regenerate all tests, type in your terminal: ```go RECORD=true go test ./lexers ``` This first sets the `RECORD` environment variable to `true`. Then it runs `go test` on the `./lexers` directory of the Chroma project. (That environment variable tells Chroma it needs to output test data. After running `go test ./lexers` you can remove or reset that variable.) ### Windows users Windows users will find that the `RECORD=true go test ./lexers` command fails in both the standard command prompt terminal and in PowerShell. Instead we have to perform both steps separately: - Set the `RECORD` environment variable to `true`. + In the regular command prompt window, the `set` command sets an environment variable for the current session: `set RECORD=true`. See [this page](https://superuser.com/questions/212150/how-to-set-env-variable-in-windows-cmd-line) for more. + In PowerShell, you can use the `$env:RECORD = 'true'` command for that. See [this article](https://mcpmag.com/articles/2019/03/28/environment-variables-in-powershell.aspx) for more. + You can also make a persistent environment variable by hand in the Windows computer settings. See [this article](https://www.computerhope.com/issues/ch000549.htm) for how. - When the environment variable is set, run `go tests ./lexers`. Chroma will now regenerate the test files and print its results to the console window.