156 lines
4.2 KiB
Rust
156 lines
4.2 KiB
Rust
// TryFrom is a simple and safe type conversion that may fail in a controlled way under some circumstances.
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// Basically, this is the same as From. The main difference is that this should return a Result type
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// instead of the target type itself.
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// You can read more about it at https://doc.rust-lang.org/std/convert/trait.TryFrom.html
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use std::convert::{TryFrom, TryInto};
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#[derive(Debug, PartialEq)]
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struct Color {
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red: u8,
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green: u8,
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blue: u8,
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}
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// I AM NOT DONE
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// Your task is to complete this implementation
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// and return an Ok result of inner type Color.
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// You need create implementation for a tuple of three integer,
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// an array of three integer and slice of integer.
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//
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// Note, that implementation for tuple and array will be checked at compile-time,
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// but slice implementation need check slice length!
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// Also note, that chunk of correct rgb color must be integer in range 0..=255.
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// Tuple implementation
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impl TryFrom<(i16, i16, i16)> for Color {
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type Error = String;
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fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {}
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}
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// Array implementation
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impl TryFrom<[i16; 3]> for Color {
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type Error = String;
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fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {}
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}
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// Slice implementation
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impl TryFrom<&[i16]> for Color {
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type Error = String;
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fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {}
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}
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fn main() {
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// Use the `from` function
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let c1 = Color::try_from((183, 65, 14));
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println!("{:?}", c1);
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// Since From is implemented for Color, we should be able to use Into
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let c2: Result<Color, _> = [183, 65, 14].try_into();
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println!("{:?}", c2);
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let v = vec![183, 65, 14];
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// With slice we should use `from` function
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let c3 = Color::try_from(&v[..]);
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println!("{:?}", c3);
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// or take slice within round brackets and use Into
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let c4: Result<Color, _> = (&v[..]).try_into();
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println!("{:?}", c4);
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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 test_tuple_out_of_range_positive() {
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assert!(Color::try_from((256, 1000, 10000)).is_err());
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}
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#[test]
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fn test_tuple_out_of_range_negative() {
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assert!(Color::try_from((-1, -10, -256)).is_err());
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}
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#[test]
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fn test_tuple_sum() {
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assert!(Color::try_from((-1, 255, 255)).is_err());
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}
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#[test]
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fn test_tuple_correct() {
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let c: Result<Color, String> = (183, 65, 14).try_into();
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assert_eq!(
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c,
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Ok(Color {
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red: 183,
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green: 65,
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blue: 14
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})
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);
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}
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#[test]
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fn test_array_out_of_range_positive() {
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let c: Color = [1000, 10000, 256].try_into();
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assert!(c.is_err());
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}
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#[test]
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fn test_array_out_of_range_negative() {
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let c: Color = [-10, -256, -1].try_into();
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assert!(c.is_err());
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}
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#[test]
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fn test_array_sum() {
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let c: Color = [-1, 255, 255].try_into();
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assert!(c.is_err());
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}
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#[test]
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#[test]
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fn test_array_correct() {
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let c: Result<Color, String> = [183, 65, 14].try_into();
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assert_eq!(
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c,
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Ok(Color {
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red: 183,
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green: 65,
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blue: 14
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})
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);
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}
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#[test]
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fn test_slice_out_of_range_positive() {
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let arr = [10000, 256, 1000];
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assert!(Color::try_from(&arr[..]).is_err());
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}
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#[test]
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fn test_slice_out_of_range_negative() {
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let arr = [-256, -1, -10];
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assert!(Color::try_from(&arr[..]).is_err());
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}
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#[test]
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fn test_slice_sum() {
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let arr = [-1, 255, 255];
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assert!(Color::try_from(&arr[..]).is_err());
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}
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#[test]
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fn test_slice_correct() {
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let v = vec![183, 65, 14];
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let c: Result<Color, String> = Color::try_from(&v[..]);
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assert_eq!(
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c,
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Ok(Color {
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red: 183,
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green: 65,
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blue: 14
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})
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);
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}
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#[test]
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fn test_slice_excess_length() {
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let v = vec![0, 0, 0, 0];
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assert!(Color::try_from(&v[..]).is_err());
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}
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#[test]
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fn test_slice_insufficient_length() {
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let v = vec![0, 0];
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assert!(Color::try_from(&v[..]).is_err());
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}
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}
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