Add quick sort tests (#3165)

src/main/java/com/thealgorithms/sorts/QuickSort.java

@@ -76,23 +76,4 @@ class QuickSort implements SortAlgorithm {
         }
         return left;
     }
-
-    // Driver Program
-    public static void main(String[] args) {
-
-        // For integer input
-        Integer[] array = {3, 4, 1, 32, 0, 1, 5, 12, 2, 5, 7, 8, 9, 2, 44, 111, 5};
-
-        QuickSort quickSort = new QuickSort();
-        quickSort.sort(array);
-
-        // Output => 0 1 1 2 2 3 4 5 5 5 7 8 9 12 32 44 111
-        print(array);
-
-        String[] stringArray = {"c", "a", "e", "b", "d"};
-        quickSort.sort(stringArray);
-
-        // Output => a	b	c	d	e
-        print(stringArray);
-    }
 }

src/test/java/com/thealgorithms/sorts/QuickSortTest.java

@@ -0,0 +1,69 @@
+package com.thealgorithms.sorts;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author Akshay Dubey (https://github.com/itsAkshayDubey)
+ * @see QuickSort
+ */
+class QuickSortTest {
+	
+	private QuickSort quickSort = new QuickSort();
+
+	@Test
+	void quickSortEmptyArrayShouldPass()
+	{
+	    Integer[] array = {};
+	    Integer[] sorted = quickSort.sort(array);
+	    Integer[] expected = {};
+	    assertArrayEquals(expected, sorted);
+	}
+
+	@Test
+	void quickSortSingleValueArrayShouldPass()
+	{
+	    Integer[] array = {7};
+	    Integer[] sorted = quickSort.sort(array);
+	    Integer[] expected = {7};
+	    assertArrayEquals(expected, sorted);
+	}
+
+	@Test
+	void quickSortWithIntegerArrayShouldPass()
+	{
+	    Integer[] array = {49,4,36,9,144,1};
+	    Integer[] sorted = quickSort.sort(array);
+	    Integer[] expected = {1,4,9,36,49,144};
+	    assertArrayEquals(expected, sorted);
+	}
+
+	@Test
+	void quickSortForArrayWithNegativeValuesShouldPass()
+	{
+	    Integer[] array = {49,-36,-144,-49,1,9};
+	    Integer[] sorted = quickSort.sort(array);
+	    Integer[] expected = {-144,-49,-36,1,9,49};
+	    assertArrayEquals(expected, sorted);
+	}
+
+	@Test
+	void quickSortForArrayWithDuplicateValuesShouldPass()
+	{
+	    Integer[] array = {36,1,49,1,4,9};
+	    Integer[] sorted = quickSort.sort(array);
+	    Integer[] expected = {1,1,4,9,36,49};
+	    assertArrayEquals(expected, sorted);
+	}
+	
+	@Test
+	void quickSortWithStringArrayShouldPass()
+	{
+	    String[] array = {"c", "a", "e", "b", "d"};
+	    String[] sorted = quickSort.sort(array);
+	    String[] expected = {"a","b","c","d","e"};
+	    assertArrayEquals(expected, sorted);
+	}
+	
+}