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