how do I test ng-add schematics

Question

I decided to add an ng-add schematic to my library, since there are additional setup steps when installing it past running npm/yarn install. This way, users will be able to run ng add @myorg/mylib and the schematics will run

I am having difficulty test running the schematic. Angular Guide only mentions how to test generate schematics, not add ones. The problem is that the schematic is supposed to run when I install the library, however ng add command always seems to install the repository version, and not the local one even if I link my library with yarn link

Thanks for your help.

Answer 1

Ok, I got an answer before I submitted the question.

Do yarn link mylibrary, and then ng add mylibrary. ng add doesn't require the library not to be installed, it will try to install, but fail gracefully if the library is already installed with a warning

Skipping installation: Package already installed

Your ng-add script probably contains context.addTask(new NodePackageInstallTask());. Since link already "installed" the library in your node_modules, this will fail. The solution is to comment this line out while you're developing, and reenable it before publishing.