如何访问板条箱的“测试”目录中的导出函数？

Question

How do I access my libraries exported functions inside the create's "tests" directory?

src/relations.rs:

#![crate_type = "lib"]

mod relations {
    pub fn foo() {
        println!("foo");
    }
}

tests/test.rs:

use relations::foo;

#[test]
fn first() {
    foo();
}

$ cargo test
   Compiling relations v0.0.1 (file:///home/chris/github/relations)
/home/chris/github/relations/tests/test.rs:1:5: 1:14 error: unresolved import `relations::foo`. Maybe a missing `extern crate relations`?
/home/chris/github/relations/tests/test.rs:1 use relations::foo;
                                                 ^~~~~~~~~

If I add the suggested extern crate relations , the error is:

/home/chris/github/relations/tests/test.rs:2:5: 2:19 error: unresolved import `relations::foo`. There is no `foo` in `relations`
/home/chris/github/relations/tests/test.rs:2 use relations::foo;
                                                 ^~~~~~~~~~~~~~

I want to test my relations in this separate tests/test.rs file. How can I solve these use issues?

Answer 1

Your problem is that, first, mod relations is not public so it is not visible outside of the crate, and second, you don't import your crate in tests.

If you build your program with Cargo, then the crate name will be the one you defined in Cargo.toml . For example, if Cargo.toml looks like this:

[package]
name = "whatever"
authors = ["Chris"]
version = "0.0.1"

[lib]
name = "relations"  # (1)

And src/lib.rs file contains this:

pub mod relations {  // (2); note the pub modifier
    pub fn foo() {
        println!("foo");
    }
}

Then you can write this in tests/test.rs :

extern crate relations;  // corresponds to (1)

use relations::relations;  // corresponds to (2)

#[test]
fn test() {
    relations::foo();
}

Answer 2

The solution was to specify a crate_id at the top of src/relations.rs:

#![crate_id = "relations"]
#![crate_type = "lib"]

pub fn foo() {
    println!("foo");
}

This seems to declare that all the contained code is part of a "relations" module, though I'm still not sure how this is different to the earlier mod block.