Please add the `test-crate` dir in your package

[tenzap]

While trying to package the crate for Debian, we noticed that it is not possible to run the test suite because you don't ship the test-crate dir.

Example of error:

error[E0432]: unresolved import `test_crate`
 --> tests/ok.rs:1:5
  |
1 | use test_crate::*;
  |     ^^^^^^^^^^ use of undeclared crate or module `test_crate`

error: cannot find macro `ok` in this scope
 --> tests/ok.rs:3:1
  |
3 | ok!(it_works);
  | ^^

[GnomedDev]

I've tried adding

include = ["src", "tests", "test-crate", "README.md"]

to the Cargo.toml but that still seems to cause this error in the output of cargo package .

PRs are welcome, but I'll take a look into this at some point.