This commit related to BAEL-7103 (#15160)

This commit aims to add a test class named "ConvertingHashSetToArrayUnitTest" that provides test methods to convert HashSet to an array.

core-java-modules/core-java-collections-5/toarraymethod/ConvertingHashSetToArrayUnitTest.java

@@ -0,0 +1,51 @@
+package com.baeldung.toarraymethod;
+
+import org.junit.Test;
+
+import java.util.HashSet;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class ConvertingHashSetToArrayUnitTest {
+
+    @Test
+    public void givenStringHashSet_whenConvertedToArray_thenArrayContainsStringElements() {
+        HashSet<String> stringSet = new HashSet<>();
+        stringSet.add("Apple");
+        stringSet.add("Banana");
+        stringSet.add("Cherry");
+
+        // Convert the HashSet of Strings to an array of Strings
+        String[] stringArray = stringSet.toArray(new String[0]);
+
+        // Test that the array is of the correct length
+        assertEquals(3, stringArray.length);
+
+        for (String str : stringArray) {
+            assertTrue(stringSet.contains(str));
+        }
+    }
+
+    @Test
+    public void givenIntegerHashSet_whenConvertedToArray_thenArrayContainsIntegerElements() {
+        HashSet<Integer> integerSet = new HashSet<>();
+        integerSet.add(5);
+        integerSet.add(10);
+        integerSet.add(15);
+
+        // Convert the HashSet of Integers to an array of Integers
+        Integer[] integerArray = integerSet.toArray(new Integer[0]);
+
+        // Test that the array is of the correct length
+        assertEquals(3, integerArray.length);
+
+        for (Integer num : integerArray) {
+            assertTrue(integerSet.contains(num));
+        }
+
+        assertTrue(integerSet.contains(5));
+        assertTrue(integerSet.contains(10));
+        assertTrue(integerSet.contains(15));
+    }
+}