Is there an equivalent of PYTHONPATH? I would like to separate my test directory

I would like to setup my folder structure like this:

.
├── LICENSE
├── src
│   └── arrow.mojo
└── test
    └── test.mojo

2 directories, 3 files

.
├── LICENSE
├── src
│   └── arrow.mojo
└── test
    └── test.mojo

2 directories, 3 files

However I can't seem to import

arrow

arrow

from

test.mojo

test.mojo

unless they are in the same directory. The error is

cannot import relative to a top-level package

cannot import relative to a top-level package