Add shuffle array (#6026)

src/test/java/com/thealgorithms/misc/ShuffleArrayTest.java

@@ -0,0 +1,84 @@
+package com.thealgorithms.misc;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class ShuffleArrayTest {
+
+    @Test
+    void testShuffleBasic() {
+        int[] arr = {1, 2, 3, 4, 5};
+        int[] originalArr = arr.clone(); // Clone original array for comparison
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is not the same as the original
+        assertNotEquals(originalArr, arr);
+    }
+
+    @Test
+    void testShuffleSingleElement() {
+        int[] arr = {1};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is the same as the original
+        assertArrayEquals(originalArr, arr);
+    }
+
+    @Test
+    void testShuffleTwoElements() {
+        int[] arr = {1, 2};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is not the same as the original
+        assertNotEquals(originalArr, arr);
+        // Check that the shuffled array still contains the same elements
+        assertTrue(arr[0] == 1 || arr[0] == 2);
+        assertTrue(arr[1] == 1 || arr[1] == 2);
+    }
+
+    @Test
+    void testShuffleEmptyArray() {
+        int[] arr = {};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is the same as the original (still empty)
+        assertArrayEquals(originalArr, arr);
+    }
+
+    @Test
+    void testShuffleLargeArray() {
+        int[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        int[] originalArr = arr.clone();
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array is not the same as the original
+        assertNotEquals(originalArr, arr);
+    }
+
+    @Test
+    void testShuffleRetainsElements() {
+        int[] arr = {1, 2, 3, 4, 5};
+        ShuffleArray.shuffle(arr);
+
+        // Check that the shuffled array contains the same elements
+        assertTrue(arr.length == 5);
+        for (int i = 1; i <= 5; i++) {
+            assertTrue(contains(arr, i));
+        }
+    }
+
+    private boolean contains(int[] arr, int value) {
+        for (int num : arr) {
+            if (num == value) {
+                return true;
+            }
+        }
+        return false;
+    }
+}