Updated 'src/io_project/test_driven_dev.md'.

projects/io_project/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "io_project"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

projects/io_project/src/lib.rs

@@ -0,0 +1,38 @@
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn one_result() {
+        let query = "duct";
+        let contents = "\
+Rust:
+safe, fast, productive.
+Pick three.";
+
+        assert_eq! (vec! ["safe, fast, productive."], search(query, contents));
+    }
+}
+
+
+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
+}
+
+pub fn run(config: Config) -> Result<(), Box<dyn Error>>{
+    let contents = fs::read_to_string(config.file_path)?;
+
+    for line in search(&config.query, &contents) {
+        println! ("{line}");
+    }
+
+    Ok(())
+}

projects/io_project/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}