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92 lines
2.4 KiB
Rust
92 lines
2.4 KiB
Rust
// This does practically the same thing that TryFrom<&str> does.
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// Additionally, upon implementing FromStr, you can use the `parse` method
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// on strings to generate an object of the implementor type.
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// You can read more about it at https://doc.rust-lang.org/std/str/trait.FromStr.html
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use std::error;
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use std::str::FromStr;
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#[derive(Debug)]
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struct Person {
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name: String,
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age: usize,
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}
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// I AM NOT DONE
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// Steps:
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// 1. If the length of the provided string is 0, an error should be returned
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// 2. Split the given string on the commas present in it
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// 3. Only 2 elements should be returned from the split, otherwise return an error
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// 4. Extract the first element from the split operation and use it as the name
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// 5. Extract the other element from the split operation and parse it into a `usize` as the age
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// with something like `"4".parse::<usize>()`
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// 5. If while extracting the name and the age something goes wrong, an error should be returned
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// If everything goes well, then return a Result of a Person object
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impl FromStr for Person {
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type Err = Box<dyn error::Error>;
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fn from_str(s: &str) -> Result<Person, Self::Err> {
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}
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}
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fn main() {
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let p = "Mark,20".parse::<Person>().unwrap();
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println!("{:?}", p);
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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 empty_input() {
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assert!("".parse::<Person>().is_err());
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}
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#[test]
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fn good_input() {
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let p = "John,32".parse::<Person>();
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assert!(p.is_ok());
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let p = p.unwrap();
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assert_eq!(p.name, "John");
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assert_eq!(p.age, 32);
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}
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#[test]
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fn missing_age() {
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assert!("John,".parse::<Person>().is_err());
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}
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#[test]
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fn invalid_age() {
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assert!("John,twenty".parse::<Person>().is_err());
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}
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#[test]
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fn missing_comma_and_age() {
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assert!("John".parse::<Person>().is_err());
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}
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#[test]
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fn missing_name() {
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assert!(",1".parse::<Person>().is_err());
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}
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#[test]
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fn missing_name_and_age() {
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assert!(",".parse::<Person>().is_err());
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}
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#[test]
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fn missing_name_and_invalid_age() {
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assert!(",one".parse::<Person>().is_err());
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}
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#[test]
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fn trailing_comma() {
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assert!("John,32,".parse::<Person>().is_err());
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}
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#[test]
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fn trailing_comma_and_some_string() {
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assert!("John,32,man".parse::<Person>().is_err());
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}
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}
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