rust - 如何在 doctest 中使用自定义模块？

Question

mod simulation;

use simulation::factory::FactoryType;

在 main.rs 中运行良好，但在 simulation/factory.rs 中的 doctest 中运行不正常:

impl product_type::ProductType for FactoryType {
    /// Lorem Ipsum
    ///
    /// # Examples
    ///
    /// ```
    /// use simulation::factory::FactoryType;
    ///
    /// ...
    /// ```
    fn human_id(&self) -> &String {
        ...
    }
}

cargo test 给我错误

---- simulation::factory::human_id_0 stdout ----
    <anon>:2:9: 2:19 error: unresolved import `simulation::factory::FactoryType`. Maybe a missing `extern crate simulation`?
<anon>:2     use simulation::factory::FactoryType;
                 ^~~~~~~~~~
error: aborting due to previous error
thread 'simulation::factory::human_id_0' panicked at 'Box<Any>', /home/rustbuild/src/rust-buildbot/slave/stable-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:192

如何让 doctest 发挥作用？

Answer 1

当您编写文档测试时，您必须充当代码的用户。鉴于这些文件:

src/lib.rs

pub mod simulation {
    pub mod factory {
        pub struct FactoryType;

        impl FactoryType {
            /// ```
            /// use foo::simulation::factory::FactoryType;
            ///
            /// let f = FactoryType;
            /// assert_eq!(42, f.human_id())
            /// ```
            pub fn human_id(&self) -> u8 { 41 }
        }
    }
}

src/main.rs

extern crate foo;
use foo::simulation::factory::FactoryType;

fn main() {
    let f = FactoryType;
    println!("{}", f.human_id());
}

一切正常。请注意，在 ma​​in.rs 中，您必须说 extern crate，然后您的所有引用都需要包含 crate 名称。 doctest 是相同的，除了 extern crate 会自动包含在内。