test: add edge-case tests for search_rotated_sorted_array

Author: bivekk51

src/searching/mod.rs

@@ -10,11 +10,11 @@ mod linear_search;
 mod moore_voting;
 mod quick_select;
 mod saddleback_search;
+mod search_rotated_sorted_array;
 mod ternary_search;
 mod ternary_search_min_max;
 mod ternary_search_min_max_recursive;
 mod ternary_search_recursive;
-mod search_rotated_sorted_array;
 
 pub use self::binary_search::binary_search;
 pub use self::binary_search_recursive::binary_search_rec;
@@ -28,10 +28,10 @@ pub use self::linear_search::linear_search;
 pub use self::moore_voting::moore_voting;
 pub use self::quick_select::quick_select;
 pub use self::saddleback_search::saddleback_search;
+pub use self::search_rotated_sorted_array::search_rotated_sorted_array;
 pub use self::ternary_search::ternary_search;
 pub use self::ternary_search_min_max::ternary_search_max;
 pub use self::ternary_search_min_max::ternary_search_min;
 pub use self::ternary_search_min_max_recursive::ternary_search_max_rec;
 pub use self::ternary_search_min_max_recursive::ternary_search_min_rec;
 pub use self::ternary_search_recursive::ternary_search_rec;
-pub use self::search_rotated_sorted_array::search_rotated_sorted_array;

src/searching/search_rotated_sorted_array.rs

@@ -71,4 +71,38 @@ mod tests {
         assert_eq!(search_rotated_sorted_array(&single, &1), Some(0));
         assert_eq!(search_rotated_sorted_array(&single, &2), None);
     }
+
+    #[test]
+    fn non_rotated_array() {
+        // already sorted ascending
+        let arr = vec![0, 1, 2, 3, 4, 5];
+        assert_eq!(search_rotated_sorted_array(&arr, &0), Some(0));
+        assert_eq!(search_rotated_sorted_array(&arr, &5), Some(5));
+        assert_eq!(search_rotated_sorted_array(&arr, &3), Some(3));
+        assert_eq!(search_rotated_sorted_array(&arr, &6), None);
+    }
+
+    #[test]
+    fn small_rotations_and_edges() {
+        // rotation by 1
+        let arr1 = vec![5, 0, 1, 2, 3, 4];
+        assert_eq!(search_rotated_sorted_array(&arr1, &5), Some(0));
+        assert_eq!(search_rotated_sorted_array(&arr1, &4), Some(5));
+
+        // rotation by len-1 (same as rotation by -1)
+        let arr2 = vec![1, 2, 3, 4, 5, 0];
+        assert_eq!(search_rotated_sorted_array(&arr2, &0), Some(5));
+        assert_eq!(search_rotated_sorted_array(&arr2, &1), Some(0));
+    }
+
+    #[test]
+    fn two_elements_varieties() {
+        let a = vec![1, 2];
+        assert_eq!(search_rotated_sorted_array(&a, &1), Some(0));
+        assert_eq!(search_rotated_sorted_array(&a, &2), Some(1));
+
+        let b = vec![2, 1];
+        assert_eq!(search_rotated_sorted_array(&b, &1), Some(1));
+        assert_eq!(search_rotated_sorted_array(&b, &2), Some(0));
+    }
 }