leetcode: can find palindrome i32 (rust)

palindrome_i32.rs

/*
Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.

Example 1:

Input: 121
Output: true

Example 2:

Input: -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.

Example 3:

Input: 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

Follow up:

Could you solve it without converting the integer to a string?



*/


// my solution
pub fn is_palindrome(x: i32) -> bool {
  let mut int_as_string = String::from(format!("{}", x));

  while int_as_string.len() > 1 {
    let head = int_as_string.remove(0);
    let tail = int_as_string.pop().unwrap();
    if head != tail { return false; }
  }
  true
}

#[cfg(test)]
mod test {
  use super::*;

  #[test]
  fn can_find_palindrome1() {
    let input1 = 121;

    let expected = true;
    assert_eq!(expected, is_palindrome(input1));
  }

  #[test]
  fn can_find_palindrome2() {
    let input1 = 2222;

    let expected = true;
    assert_eq!(expected, is_palindrome(input1));
  }

  #[test]
  fn can_find_palindrome3() {
    let input1 = 0;

    let expected = true;
    assert_eq!(expected, is_palindrome(input1));
  }

  #[test]
  fn can_find_palindrome4() {
    let input1 = 1234;

    let expected = false;
    assert_eq!(expected, is_palindrome(input1));
  }

}