How to prevent mix test to start Application

There are a few options there:

• write the children list of your app supervision tree to conditionally not start children that shouldn’t start in test environment.
• configure your ws client to not log in test environment.
• wrap your ws client around an adapter and mock it(using mox, probably) in tests.

I usually do the first one. using the configs for it. so my test.exs file has something like:

config :myapp, MyApp.SupChild,
enable: false,
...

and in the application.ex I have something like:

[
  Myapp.Repo,
  MyApp.Endpoint,
...
]
++
load(MyApp.SupChild)

where load/1 checks the application config for the enable key.

You can see that in action with phoenix, which starts the TCP parts of an endpoint only if configured to do so using config :my_app, MyAppWeb.Endpoint, server: true. mix phx.server is just a mix task enabling that config before starting the application. If the config is missing the “server” won’t be started.

Thank you that actually makes a lot of sense and its super simple! I did it and it worked yeah