iterators3: Add `IntegerOverflow` error variant

1 files changed, 13 insertions, 0 deletions

diff --git a/solutions/18_iterators/iterators3.rs b/solutions/18_iterators/iterators3.rs
index d66d1ef..11aa1ec 100644
--- a/solutions/18_iterators/iterators3.rs
+++ b/solutions/18_iterators/iterators3.rs
@@ -1,6 +1,10 @@
 #[derive(Debug, PartialEq, Eq)]
 enum DivisionError {
+    // Example: 42 / 0
     DivideByZero,
+    // Only case for `i64`: `i64::MIN / -1` because the result is `i64::MAX + 1`
+    IntegerOverflow,
+    // Example: 5 / 2 = 2.5
     NotDivisible,
 }
 
@@ -9,6 +13,10 @@ fn divide(a: i64, b: i64) -> Result<i64, DivisionError> {
         return Err(DivisionError::DivideByZero);
     }
 
+    if a == i64::MIN && b == -1 {
+        return Err(DivisionError::IntegerOverflow);
+    }
+
     if a % b != 0 {
         return Err(DivisionError::NotDivisible);
     }
@@ -52,6 +60,11 @@ mod tests {
     }
 
     #[test]
+    fn test_integer_overflow() {
+        assert_eq!(divide(i64::MIN, -1), Err(DivisionError::IntegerOverflow));
+    }
+
+    #[test]
     fn test_not_divisible() {
         assert_eq!(divide(81, 6), Err(DivisionError::NotDivisible));
     }