diff --git a/test/unit/utils.js b/test/unit/utils.js
new file mode 100644
index 0000000..19eaf72
--- /dev/null
+++ b/test/unit/utils.js
@@ -0,0 +1,29 @@
+'use strict';
+
+/* eslint-env node, mocha */
+
+const { assert } = require('chai');
+
+const utils = require('../../lib/utils');
+
+describe('utils', () => {
+	describe('dateRange', () => {
+		describe('dateRange', () => {
+			it('should generate empty object with partial parameters', () => {
+				assert.isEmpty(utils.dateRange());
+			});
+			it('should throw with invalid date', () => {
+				assert.throws(() => utils.dateRange('2018-15-15', '2018-20-20'));
+			});
+			it('should work for valid string input', () => {
+				assert.containsAllDeepKeys(utils.dateRange('2018-01-15', '2018-01-20'), { DateRange: { Start: '2018-01-15', End: '2018-01-20' } });
+			});
+			it('should work for Date string input', () => {
+				assert.containsAllDeepKeys(utils.dateRange(new Date('2018-01-15'), new Date('2018-01-20')), { DateRange: { Start: '2018-01-15', End: '2018-01-20' } });
+			});
+			it('should work for timestamp string input', () => {
+				assert.containsAllDeepKeys(utils.dateRange(new Date('2018-01-15').getTime(), new Date('2018-01-20').getTime()), { DateRange: { Start: '2018-01-15', End: '2018-01-20' } });
+			});
+		});
+	});
+});