Integration tests extern crate: can't find crate error

I have a few files in the src folder which I use in main.rs like so:

   mod client;
   mod node;
   use client::client_add;
   use node::node_add;

and between the files themselves like so:

use crate::client::client_add;

Cargo builds and runs as it's supposed to.

However, if I try to import one of the files in the tests/integration_tests.rs like so:

extern crate node;

, I'm getting the can't find crate error. There is not much more information on integration tests in the Rust book.

What am I missing?

Here's a link to the project to make the structure clear:
test project

test-mod is the crate, in a library you would export the modules like pub mod node;. What you have is instead is just a executable.

Have a read through this, it complements other books.
https://rust-lang-nursery.github.io/cli-wg/tutorial/testing.html

Thanks for the link to the book, it's very informative. I suppose there is nothing like testing binary crates in external tests. It's either a lib, or no integration tests. Unless we use std::process::Command;. Thank you for the reply.