I cannot configure angular-cli + scss + karma to test my components together. Running ng test the kamra unit tests are only including the components\' own scss          
        
Angular CLI already uses node-sass if you configure it to use sass. So there is no need to install it again:
npm install karma-scss-preprocessor --save-dev
should be sufficient. Plus you don't have multiple versions of node-sass in your project.
The rest of the solution of @istibekesi works like charm.