Issue 97 bubble sort

src/main/java/com/ordestiny/tdd/algorithms/SortingAlgorithms.java

@@ -0,0 +1,29 @@
+package com.ordestiny.tdd.algorithms;
+
+public class SortingAlgorithms {
+
+    /**
+     * Sorting algorithm that works by repeatedly swapping the adjacent elements if they are in decreasing order.
+     * @param array
+     */
+    public static int[] bubbleSort(int[] array) {
+        for (int i = 0; i < array.length - 1; i++)
+            for (int j = i + 1; j < array.length; j++)
+                if (array[i] > array[j])
+                    swap(i, j, array);
+        return array;
+    }
+
+    /**
+     * Swaps values at given indices for an array.
+     * @param i
+     * @param j
+     * @param array
+     */
+    private static void swap(int i, int j, int[] array) {
+        int temp = array[i];
+        array[i] = array[j];
+        array[j] = temp;
+    }
+
+}

src/test/java/com/ordestiny/tdd/algorithms/BubbleSortTest.java

@@ -0,0 +1,22 @@
+package com.ordestiny.tdd.algorithms;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class BubbleSortTest {
+
+    private final int[] notSortedArray = {8, 7, 6, 5, 4, 3, 2, 1, 0};
+    private final int[] sortedArray = {0, 1, 2, 3, 4, 5, 6, 7, 8};
+
+    @Test
+    public void bubbleSort_IntegerArray_notSorted() {
+        assertArrayEquals(sortedArray, SortingAlgorithms.bubbleSort(notSortedArray));
+    }
+
+    @Test
+    public void bubbleSort_IntegerArray_sorted() {
+        assertArrayEquals(sortedArray, SortingAlgorithms.bubbleSort(sortedArray));
+    }
+
+}