How to share a file in test files?

I have this hierarchy in my substrate pallet:

src/
├── lib.rs
├── mock.rs
├── tests.rs
└── common.rs
Cargo.toml

My mock.rs and tests.rs need to share some constants and types, so I put those into common.rs.

in my mock.rs and tests.rs:

mod common;
use crate::common::{
        TOKEN_TRANSFER_FEE, Balance,
};

in my common.rs:

pub mod common {
  pub type Balance = u128;

  pub const TOKEN_TRANSFER_FEE: Balance = 1_000;
}

then I got these errors:

error[E0583]: file not found for module `common`
  --> pallets/bridge/src/mock.rs:48:1
   |
48 | mod common;
   | ^^^^^^^^^^^
   |
   = help: to create the module `common`, create file "pallets/bridge/src/mock/common.rs" or "pallets/bridge/src/mock/common/mod.rs"

error[E0583]: file not found for module `common`
  --> pallets/bridge/src/tests.rs:36:1
   |
36 | mod common;
   | ^^^^^^^^^^^
   |
   = help: to create the module `common`, create file "pallets/bridge/src/tests/common.rs" or "pallets/bridge/src/tests/common/mod.rs"

Is there an easier way to import those constants and types from that shared common file into mock.rs and tests.rs, instead of making mock folder and tests folders?

Use only mod once and in the other files use:

lib

mod common;
mod mock;

fn entry() {
    eprintln!("{}", common::common::TEST);
}

common

pub mod common {
    pub const TEST: &str = "";
}

mock

use crate::common;

fn mock() {
    eprintln!("{}", common::common::TEST);
}