pub fn find_matches(content: &str, pattern: &str, mut writer: impl std::io::Write) {
for line in content.lines() {
if line.contains(pattern) {
writeln!(writer, "{}", line);
}
}
}
#[test]
fn find_a_match() {
let mut result = Vec::new();
find_matches("lorem ipsum\ndolor sit amet", "lorem", &mut result);
assert_eq!(result, b"lorem ipsum\n");
}