TailwindCSS v4 - postCSS issue while running test (Jasmine and Karma)

[DSplawski-CC]

Which @angular/* package(s) are the source of the bug?

Don't known / other

Is this a regression?

No

Description

Just created Angular project in webstorm and followed instruction to install and configure tailwindcss for Angular
https://tailwindcss.com/docs/installation/framework-guides/angular

It works fine in development or production, but it does not work when trying to run test via ng test (Jasmine and Karma)

`

Please provide a link to a minimal reproduction of the bug

https://github.com/DSplawski-CC/AngularTailwindCss

Please provide the exception or error you saw

`An unhandled exception occurred: It looks like you're trying to use `tailwindcss` directly as a PostCSS plugin. The PostCSS plugin has moved to a separate package, so to continue using Tailwind CSS with PostCSS you'll need to install `@tailwindcss/postcss` and update your PostCSS configuration.
`
`
at Re (F:\AngularTailwindCss\node_modules\tailwindcss\dist\lib.js:33:1716)
    at getStylesConfig (F:\AngularTailwindCss\node_modules\@angular-devkit\build-angular\src\tools\webpack\configs\styles.js:106:66)
    at async Promise.all (index 1)
    at async generateWebpackConfig (F:\AngularTailwindCss\node_modules\@angular-devkit\build-angular\src\utils\webpack-browser-config.js:74:22)
    at async generateBrowserWebpackConfigFromContext (F:\AngularTailwindCss\node_modules\@angular-devkit\build-angular\src\utils\webpack-browser-config.js:129:20)
    at async initializeBrowser (F:\AngularTailwindCss\node_modules\@angular-devkit\build-angular\src\builders\karma\browser_builder.js:109:24)

Please provide the environment you discovered this bug in (run ng version)

Angular CLI: 19.1.8
Node: 22.9.0
Package Manager: npm 11.0.0
OS: win32 x64

Angular: 19.1.7
... animations, common, compiler, compiler-cli, core, forms
... platform-browser, platform-browser-dynamic, router

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.1901.8
@angular-devkit/build-angular   19.1.8
@angular-devkit/core            19.1.8
@angular-devkit/schematics      19.1.8
@angular/cli                    19.1.8
@schematics/angular             19.1.8
rxjs                            7.8.1
typescript                      5.7.3
zone.js                         0.15.0

Anything else?

No response

[JoostK]

This is expected; the webpack-based builder does not read the postcss configuration file from the workspace, only the application-builder does. Tailwind v4 support is tracked in #28938.

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