Rust + cargo

方針

• Rust では、標準のテストランナー（cargo test と #[test] 属性）を使う

前提

bash

brew install rust

プロジェクト作成

bash

mkdir -p ~/workdir
cd ~/workdir
cargo new sample-cargo --lib
code sample-cargo

最小のコード

src/lib.rs

pub fn add(a: u64, b: u64) -> u64 {
    return a + b;
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn two_plus_three_is_five() {
        assert_eq!(add(2, 3), 5);
    }
}

決まりごと

• テスト用のモジュールに #[cfg(test)] 属性をつける
• テスト関数に #[test] 属性をつける
• メソッド内で assert_eq! などのマッチメソッドを呼ぶ

実行

bash

cargo test

表示例

成功時

txt

   Compiling sample-cargo v0.1.0 (/Users/takaaki/workdir/sample-cargo)
    Finished `test` profile [unoptimized + debuginfo] target(s) in 0.12s
     Running unittests src/lib.rs (target/debug/deps/sample_cargo-e7ae0abce5e33dac)

running 1 test
test tests::two_plus_three_is_five ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

   Doc-tests sample_cargo

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

失敗時

txt

   Compiling sample-cargo v0.1.0 (/Users/takaaki/workdir/sample-cargo)
    Finished `test` profile [unoptimized + debuginfo] target(s) in 0.11s
     Running unittests src/lib.rs (target/debug/deps/sample_cargo-e7ae0abce5e33dac)

running 1 test
test tests::two_plus_three_is_five ... FAILED

failures:

---- tests::two_plus_three_is_five stdout ----

thread 'tests::two_plus_three_is_five' (1048249) panicked at src/lib.rs:11:9:
assertion `left == right` failed
  left: 6
 right: 5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    tests::two_plus_three_is_five

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

error: test failed, to rerun pass `--lib`