Cargo test fails on `env_var_mask:works_from_any_dir`

[twitu]

failures:

---- env_var_mask::works_from_any_dir stdout ----
thread 'env_var_mask::works_from_any_dir' panicked at 'Unexpected stdout, failed var.contains("tests passed")
└── var as str: 

command=`"/home/twitu/Code/mask/target/debug/mask" "--maskfile" "/tmp/.tmpgB48C0/maskfile.md" "ci"`
code=127
stdout=``````
stderr=```bash: mask: command not found

If I understand correctly it's failing simply because mask executable is not installed $PATH. I tried running this after doing cargo install mask and the test passed.

Should a source code test depend on the executable being installed externally? If this is the desired behaviour it could be mentioned in the README somewhere that the executable should be installed before running tests.

Mask version: 7c31651
Cargo version: 1.43.0
OS: Ubuntu 20.04
Terminal: zsh

[jacobdeichert]

Ahhh this is a lack of documentation I think. I usually run mask link and then mask test... but that depends on mask being installed first....

I'll update the contributing docs