diff --git a/tests/lib/format.py b/tests/lib/format.py
new file mode 100644
index 000000000..0c5f5b28c
--- /dev/null
+++ b/tests/lib/format.py
@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+# -*- coding:utf-8 -*-
+#
+# @name   : PhoneInfoga - Phone numbers OSINT tool
+# @url    : https://github.com/sundowndev
+# @author : Raphael Cerveaux (sundowndev)
+
+import unittest
+from unittest.mock import patch
+
+from lib.format import formatNumber, replaceVariables
+
+
+class TestFormat(unittest.TestCase):
+    """
+    We want to be sure re.sub is imported and called
+    """
+
+    @patch("re.sub")
+    def test_formatNumberCallingSub(self, subMock):
+        subMock.return_value = ""
+
+        result = formatNumber("000")
+
+        subMock.assert_called_with("(?:\+)?(?:[^[0-9]*)", "", "000")
+        self.assertEqual(result, "")
+
+    """
+    We verify the function formats the number the right way
+    """
+
+    def test_formatNumber(self):
+        self.assertEqual(formatNumber("+33 81495357"), "3381495357")
+        self.assertEqual(formatNumber("0 81 49 53 57"), "081495357")
+        self.assertEqual(formatNumber("+1 555-444-888"), "1555444888")
+
+    def test_replaceVariables(self):
+        number = {
+            "input": "+33651580074",
+            "default": "33651580074",
+            "local": "651580074",
+            "international": "+33 6 51 58 00 74",
+            "country": "France",
+            "countryCode": "+33",
+            "countryIsoCode": "FR",
+            "location": "France",
+            "carrier": "",
+        }
+
+        self.assertEqual(replaceVariables("test $n", number), "test 33651580074")
+        self.assertEqual(
+            replaceVariables("test $i", number), "test +33 6 51 58 00 74"
+        )
+        self.assertEqual(replaceVariables("test $l", number), "test 6 51 58 00 74")