Check partition method

src/test/java/com/github/pedrovgs/problem80/PartitionTest.java

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+package com.github.pedrovgs.problem80;
+
+import static org.junit.Assert.assertTrue;
+import org.junit.jupiter.api.Test;
+import junit.framework.AssertionFailedError;
+import com.github.pedrovgs.sortingalgorithm.SortingAlgorithm;
+import com.github.pedrovgs.sortingalgorithms.SortingAlgorithmTest;
+
+public class PartitionTest {
+	@Test
+	// Partition 1: array with multiple positive elements
+	public void testMultiplePositiveElements() {
+		int[] arr = {2,4,7,3,9,1,8};
+		QuickSort quickSortObject = new QuickSort();
+		assertTrue("Error in partition() method: array with multiple positive elements", 5 == quickSortObject.partition(arr, 0, 6));
+	}
+
+	@Test
+	// Partition 2: array with multiple negative elements
+	public void testMultipleNegativeElements() {
+		int[] arr = {-2,-4,-7,-3,-9,-1,-8};
+		QuickSort quickSortObject = new QuickSort();
+		assertTrue("Error in partition() method: array with multiple negative elements", 1 == quickSortObject.partition(arr, 0, 6));
+	}
+
+	@Test
+	// Partition 3: array with multiple mixed elements
+	public void testMultipleMixedElements() {
+		int[] arr = {-2,4,7,-3,-9,1,8};
+		QuickSort quickSortObject = new QuickSort();
+		assertTrue("Error in partition() method: array with multiple mixed elements", 6 == quickSortObject.partition(arr, 0, 6));
+	}
+
+	@Test
+	// Partition 4: array with no element
+	public void testNoElement() {
+		int[] arr = {};
+		QuickSort quickSortObject = new QuickSort();
+		try {
+			quickSortObject.partition(arr, 0, 0);
+		} catch (ArrayIndexOutOfBoundsException e){
+			throw new AssertionFailedError (e.getMessage());
+		}
+	}
+
+	@Test
+	// Partition 5: array with one element
+	public void testOneElement() {
+		int[] arr = {2};
+		QuickSort quickSortObject = new QuickSort();
+		try {
+			quickSortObject.partition(arr, 0, 1);
+		} catch (ArrayIndexOutOfBoundsException e){
+			throw new AssertionFailedError (e.getMessage());
+		}
+	}
+}