chay.dev
1fn trim_me(input: &str) -> &str {
2 input.trim()
3}
4
5fn compose_me(input: &str) -> String {
6 // The macro `format!` has the same syntax as `println!`, but it returns a
7 // string instead of printing it to the terminal.
8 // Equivalent to `input.to_string() + " world!"`
9 format!("{input} world!")
10}
11
12fn replace_me(input: &str) -> String {
13 input.replace("cars", "balloons")
14}
15
16fn main() {
17 // You can optionally experiment here.
18}
19
20#[cfg(test)]
21mod tests {
22 use super::*;
23
24 #[test]
25 fn trim_a_string() {
26 assert_eq!(trim_me("Hello! "), "Hello!");
27 assert_eq!(trim_me(" What's up!"), "What's up!");
28 assert_eq!(trim_me(" Hola! "), "Hola!");
29 }
30
31 #[test]
32 fn compose_a_string() {
33 assert_eq!(compose_me("Hello"), "Hello world!");
34 assert_eq!(compose_me("Goodbye"), "Goodbye world!");
35 }
36
37 #[test]
38 fn replace_a_string() {
39 assert_eq!(
40 replace_me("I think cars are cool"),
41 "I think balloons are cool",
42 );
43 assert_eq!(
44 replace_me("I love to look at cars"),
45 "I love to look at balloons",
46 );
47 }
48}