Test some stuff on a small codebase.
The EnvironmentService is used as a provider in 3 modules: app.module, chat.module and shared.module.
Every time it is used as a provider, the constructor is called.
This can cause problem, when calling app.get(EnvironmentService) you get a different instance that the one used in PostMessageService.
However, across the app, the same EnvironmentService instance is used.
When done properly, BetterEnvService is put only once in a provider, then it is reused thanks to the imports/exports directive.
To verify this, run yarn test and watch the logs.