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Diffstat (limited to 'exercises/error_handling/errorsn.rs')
| -rw-r--r-- | exercises/error_handling/errorsn.rs | 117 |
1 files changed, 0 insertions, 117 deletions
diff --git a/exercises/error_handling/errorsn.rs b/exercises/error_handling/errorsn.rs deleted file mode 100644 index 5fe212b..0000000 --- a/exercises/error_handling/errorsn.rs +++ /dev/null @@ -1,117 +0,0 @@ -// errorsn.rs -// This is a bigger error exercise than the previous ones! -// You can do it! :) -// -// Edit the `read_and_validate` function ONLY. Don't create any Errors -// that do not already exist. -// -// So many things could go wrong! -// -// - Reading from stdin could produce an io::Error -// - Parsing the input could produce a num::ParseIntError -// - Validating the input could produce a CreationError (defined below) -// -// How can we lump these errors into one general error? That is, what -// type goes where the question marks are, and how do we return -// that type from the body of read_and_validate? -// -// Execute `rustlings hint errorsn` for hints :) - -// I AM NOT DONE - -use std::error; -use std::fmt; -use std::io; - -// PositiveNonzeroInteger is a struct defined below the tests. -fn read_and_validate(b: &mut dyn io::BufRead) -> Result<PositiveNonzeroInteger, ???> { - let mut line = String::new(); - b.read_line(&mut line); - let num: i64 = line.trim().parse(); - let answer = PositiveNonzeroInteger::new(num); - answer -} - -// -// Nothing below this needs to be modified -// - -// This is a test helper function that turns a &str into a BufReader. -fn test_with_str(s: &str) -> Result<PositiveNonzeroInteger, Box<dyn error::Error>> { - let mut b = io::BufReader::new(s.as_bytes()); - read_and_validate(&mut b) -} - -#[test] -fn test_success() { - let x = test_with_str("42\n"); - assert_eq!(PositiveNonzeroInteger(42), x.unwrap()); -} - -#[test] -fn test_not_num() { - let x = test_with_str("eleven billion\n"); - assert!(x.is_err()); -} - -#[test] -fn test_non_positive() { - let x = test_with_str("-40\n"); - assert!(x.is_err()); -} - -#[test] -fn test_ioerror() { - struct Broken; - impl io::Read for Broken { - fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> { - Err(io::Error::new(io::ErrorKind::BrokenPipe, "uh-oh!")) - } - } - let mut b = io::BufReader::new(Broken); - assert!(read_and_validate(&mut b).is_err()); - assert_eq!("uh-oh!", read_and_validate(&mut b).unwrap_err().to_string()); -} - -#[derive(PartialEq, Debug)] -struct PositiveNonzeroInteger(u64); - -impl PositiveNonzeroInteger { - fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> { - if value == 0 { - Err(CreationError::Zero) - } else if value < 0 { - Err(CreationError::Negative) - } else { - Ok(PositiveNonzeroInteger(value as u64)) - } - } -} - -#[test] -fn test_positive_nonzero_integer_creation() { - assert!(PositiveNonzeroInteger::new(10).is_ok()); - assert_eq!( - Err(CreationError::Negative), - PositiveNonzeroInteger::new(-10) - ); - assert_eq!(Err(CreationError::Zero), PositiveNonzeroInteger::new(0)); -} - -#[derive(PartialEq, Debug)] -enum CreationError { - Negative, - Zero, -} - -impl fmt::Display for CreationError { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - let description = match *self { - CreationError::Negative => "Number is negative", - CreationError::Zero => "Number is zero", - }; - f.write_str(description) - } -} - -impl error::Error for CreationError {} |
