diff --git a/src/_Problems_/merge-two-sorted-arrays/index.js b/src/_Problems_/merge-two-sorted-arrays/index.js
index 5355c789..55c89f7f 100644
--- a/src/_Problems_/merge-two-sorted-arrays/index.js
+++ b/src/_Problems_/merge-two-sorted-arrays/index.js
@@ -38,3 +38,8 @@ function mergeTwoSortedArrays(arr1, arr2) {
 function mergeTwoSortedArrays2(arr1, arr2) {
   return [...arr1, ...arr2].sort((a, b) => a - b);
 }
+
+module.exports = {
+  mergeTwoSortedArrays,
+  mergeTwoSortedArrays2,
+};
diff --git a/src/_Problems_/merge-two-sorted-arrays/merge-two-sorted-arrays.test.js b/src/_Problems_/merge-two-sorted-arrays/merge-two-sorted-arrays.test.js
new file mode 100644
index 00000000..5a3d4cc7
--- /dev/null
+++ b/src/_Problems_/merge-two-sorted-arrays/merge-two-sorted-arrays.test.js
@@ -0,0 +1,46 @@
+const { mergeTwoSortedArrays, mergeTwoSortedArrays2 } = require('.');
+
+
+describe('Merge Two Sorted Array which are already in ascending order ', () => {
+  let array1 = [];
+  let array2 = [];
+
+  describe('When array[i]-array[j] = 1 where i>j & j>=0', () => {
+    beforeEach(() => {
+      array1 = [1, 2, 3, 4, 5];
+      array2 = [6, 7, 8];
+    });
+    it('Merge two sort array with complexity O(n+m)', () => {
+      expect(mergeTwoSortedArrays(array1, array2)).toEqual([1, 2, 3, 4, 5, 6, 7, 8]);
+    });
+    it('Merge two sort array with complexity O(nlogn)', () => {
+      expect(mergeTwoSortedArrays2(array1, array2)).toEqual([1, 2, 3, 4, 5, 6, 7, 8]);
+    });
+  });
+
+  describe('When array[i]-array[j] => 1 where i>j & j>=0', () => {
+    beforeEach(() => {
+      array1 = [1, 3, 5, 6, 98, 100];
+      array2 = [2, 4, 99];
+    });
+    it('Merge two sort array with complexity O(n+m)', () => {
+      expect(mergeTwoSortedArrays(array1, array2)).toEqual([1, 2, 3, 4, 5, 6, 98, 99, 100]);
+    });
+    it('Merge two sort array with complexity O(nlogn)', () => {
+      expect(mergeTwoSortedArrays2(array1, array2)).toEqual([1, 2, 3, 4, 5, 6, 98, 99, 100]);
+    });
+  });
+
+  describe('When array[i]-array[j] <= 1  where i>j & j>=0', () => {
+    beforeEach(() => {
+      array1 = [1, 1, 5, 6, 98, 100];
+      array2 = [4, 4, 99];
+    });
+    it('Merge two sort array with complexity O(n+m)', () => {
+      expect(mergeTwoSortedArrays(array1, array2)).toEqual([1, 1, 4, 4, 5, 6, 98, 99, 100]);
+    });
+    it('Merge two sort array with complexity O(nlogn)', () => {
+      expect(mergeTwoSortedArrays2(array1, array2)).toEqual([1, 1, 4, 4, 5, 6, 98, 99, 100]);
+    });
+  });
+});