测试驱动开发

TDD (Test-Driven Development)

  • 编写一个会失败的测试，运行该测试，确保它是按照预期的原因失败
  • 编写或修改刚好足够的代码，让新测试通过
  • 重构刚刚添加或修改的代码，确保测试会始终通过
  • 返回步骤1，继续

    添加搜索逻辑

    ```rust // lib.rs use std::error::Error; use std::fs;

pub fn run(config: Config) -> Result<(), Box> { let contents = fs::read_to_string(config.filename)?; for line in search(&config.query, &contents) { println!(“{}”, line); } Ok(()) }

pub struct Config { pub query: String, pub filename: String, }

impl Config { pub fn new(args: &[String]) -> Result<Config, &’static str> { if args.len() < 3 { return Err(“not enough arguments”); } let query = args[1].clone(); let filename = args[2].clone(); Ok(Config { query, filename }) } }

pub fn search<’a>(query: &str, contents: &’a str) -> Vec<&’a str> { let mut results = Vec::new(); for line in contents.lines() { if line.contains(query) { results.push(line); } } results }

[cfg(test)]

mod tests { use super::*;

[test]

fn one_result() { let query = “duct”; let contents = “\ Rust: safe, fast, productive. Pick three.”;

  1. assert_eq!(vec!["safe, fast, productive."], search(query, contents));

} } ```