Error when trying to open a file inside a docker with Elixir

I’m inside a docker, running a test and trying to open a file using File.open.

This is my test code:

upload = %Plug.Upload{
        filename: "funcionarios.csv",
        path: Path.expand("/home/company/code/project/apps/project_web/test/project_2/resolver/funcionarios.csv", __DIR__)
      }

This is the error I get:

** (File.Error) could not open “/home/company/code/project/apps/project_web/test/project_2/resolver/funcionarios.csv”: no such file or directory

What am I doing wrong?

Source: StackOverflow