42 lines
1.2 KiB
Rust
42 lines
1.2 KiB
Rust
// TODO: This function refuses to generate text to be printed on a nametag if
|
|
// you pass it an empty string. It'd be nicer if it explained what the problem
|
|
// was instead of just returning `None`. Thankfully, Rust has a similar
|
|
// construct to `Option` that can be used to express error conditions. Change
|
|
// the function signature and body to return `Result<String, String>` instead
|
|
// of `Option<String>`.
|
|
fn generate_nametag_text(name: String) -> Option<String> {
|
|
if name.is_empty() {
|
|
// Empty names aren't allowed
|
|
None
|
|
} else {
|
|
Some(format!("Hi! My name is {name}"))
|
|
}
|
|
}
|
|
|
|
fn main() {
|
|
// You can optionally experiment here.
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn generates_nametag_text_for_a_nonempty_name() {
|
|
assert_eq!(
|
|
generate_nametag_text("Beyoncé".to_string()).as_deref(),
|
|
Ok("Hi! My name is Beyoncé"),
|
|
);
|
|
}
|
|
|
|
#[test]
|
|
fn explains_why_generating_nametag_text_fails() {
|
|
assert_eq!(
|
|
generate_nametag_text(String::new())
|
|
.as_ref()
|
|
.map_err(|e| e.as_str()),
|
|
Err("Empty names aren't allowed"),
|
|
);
|
|
}
|
|
}
|