rust - trouble importing module - module

Question

I have encountered a strange error preventing one of my files from importing a module
This is my src directory
src/
functions.rs
main.rs
unit_test.rs
Here is unit_test.rs
mod functions;
#[cfg(test)] // only compiles on test
// make module f_test
mod f_test{
// mark function as test
#[test]
#[should_panic]
fn test_basic() {
assert_eq!();
panic!("oh no");
}
#[test]
fn test_add(){
assert_eq!(functions::add(1,2), 1 + 2);
}
#[test]
#[should_panic]
fn test_bad_add(){
assert_eq!(functions::add(1,2), 1 + 2);
}
}
When I try to run cargo test I get this
[vinessa#komputilo unitTest]$ cargo test
Compiling unitTest v0.1.0 (/home/vinessa/Dev/Rust/unitTest)
error[E0583]: file not found for module `functions`
--> src/unit_test.rs:1:5
|
1 | mod functions;
| ^^^^^^^^^
|
= help: name the file either unit_test/functions.rs or unit_test/functions/mod.rs inside the directory "src"
Strange thing, if I add "mod functions;" to main.rs, cargo won't complain about that file, only for unit_test.rs
I am lost please help

Answer 1

I think you want to declare mod functions in main.rs:
mod unit_test;
mod functions; // declare this module here
fn main() {
println!("Hello, world!");
}
I think you want this in unit_test.rs:
#[cfg(test)] // only compiles on test
// make module f_test
mod f_test{
use crate::functions; // use module here
// mark function as test
#[test]
#[should_panic]
fn test_basic() {
assert_eq!(1, 1);
panic!("oh no");
}
#[test]
fn test_add(){
assert_eq!(functions::add(1,2), 1 + 2);
}
#[test]
#[should_panic]
fn test_bad_add(){
assert_eq!(functions::add(1,2), 1 + 2);
}
}
Additionally, your #[should_panic] is incorrect as it stands.
Obligatory link: https://doc.rust-lang.org/book/ch07-02-defining-modules-to-control-scope-and-privacy.html