Setup fake timers for jest

Author: Damian Sznajder

.npmignore

@@ -5,3 +5,4 @@ node_modules/
 README.md
 CHANGELOG.md
 LICENCE
+__tests__

jest/setup.js

@@ -0,0 +1 @@
+jest.useFakeTimers();

package.json

@@ -40,6 +40,9 @@
     "testEnvironment": "node",
     "preset": "react-native",
     "testRegex": "/__tests__/.*\\.(test)\\.(js|tsx?)$",
+    "setupFiles": [
+      "./jest/setup"
+    ],
     "modulePathIgnorePatterns": [
       "<rootDir>/Example"
     ]

src/__tests__/helpers.test.js

@@ -0,0 +1,25 @@
+import { fillOtpCode } from '../helpers';
+
+describe('fillOtpCode', () => {
+  test('with only number of inputs', () => {
+    expect(fillOtpCode(6)).toEqual({
+      '0': '',
+      '1': '',
+      '2': '',
+      '3': '',
+      '4': '',
+      '5': '',
+    });
+  });
+
+  test('with number and code', () => {
+    expect(fillOtpCode(6, 'code')).toEqual({
+      '0': 'c',
+      '1': 'o',
+      '2': 'd',
+      '3': 'e',
+      '4': '',
+      '5': '',
+    });
+  });
+});