I tried several times to convert our angular mono repo to use jest but without success. I created sample project that contains 2 project inside 1.my-app 2.my-lib

This is the tree of the projects:

each of the projects contains his tsconfig.spec.json file on the root level I have angular.json , package.json and tsconfig.json.

I try several approaches angular-builder\angular-devkit \ delete test configuration from angular.json and run the jest commands.

With or without jest.config and setup-jest file and also with jest-preset-angular.

Bottom line it's not working or jest not find the files from the lib project or he claims

" [ERROR] File 'appponent.spec.ts' is missing from the TypeScript compilation. [plugin angular-compiler]

Ensure the file is part of the TypeScript program via the 'files' or 'include' property."

also here nothing helped.