diff --git a/app/Http/Requests/Accounts/RegisterRequest.php b/app/Http/Requests/Accounts/RegisterRequest.php
index 3c4b6de..d3cb983 100644
--- a/app/Http/Requests/Accounts/RegisterRequest.php
+++ b/app/Http/Requests/Accounts/RegisterRequest.php
@@ -32,23 +32,4 @@ class RegisterRequest extends Request
             'password_confirmation' => 'required',
         ];
     }
-
-    /**
-     * Get custom messages for validator errors.
-     *
-     * @return array
-     */
-    public function messages()
-    {
-        return [
-            'name.required'                  => 'Nama harus diisi.',
-            'email.required'                 => 'Email harus diisi.',
-            'email.email'                    => 'Email tidak valid.',
-            'email.unique'                   => 'Email ini sudah terdaftar.',
-            'password.required'              => 'Password harus diisi.',
-            'password.between'               => 'Password baru harus antara 6 - 15 karakter.',
-            'password.confirmed'             => 'Konfirmasi password tidak sesuai.',
-            'password_confirmation.required' => 'Konfirmasi password harus diisi.',
-        ];
-    }
 }
diff --git a/app/helpers.php b/app/helpers.php
index 3c8044b..6862aa7 100755
--- a/app/helpers.php
+++ b/app/helpers.php
@@ -159,6 +159,14 @@ function html_link_to_route($name, $title = null, $parameters = [], $attributes
     return app('html')->decode(link_to_route($name, $title, $parameters, $attributes));
 }
 
+/**
+ * Period between two dates.
+ *
+ * @param  string  $date1
+ * @param  string  $date2
+ * @param  string  $differenceFormat
+ * @return int|string
+ */
 function dateDifference($date1, $date2, $differenceFormat = '%a')
 {
     $datetime1 = date_create($date1);
diff --git a/tests/Unit/Helpers/DateDifferenceTest.php b/tests/Unit/Helpers/DateDifferenceTest.php
new file mode 100644
index 0000000..6984536
--- /dev/null
+++ b/tests/Unit/Helpers/DateDifferenceTest.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace Tests\Unit\Helpers;
+
+use Tests\TestCase;
+
+/**
+ * Date Difference Helper Unit Test.
+ *
+ * @author Nafies Luthfi <nafiesL@gmail.com>
+ */
+class DateDifferenceTest extends TestCase
+{
+    /** @test */
+    public function date_difference_function_exists()
+    {
+        $this->assertTrue(function_exists('dateDifference'));
+    }
+
+    /** @test */
+    public function date_difference_returns_days_count_by_default()
+    {
+        $this->assertEquals(9, dateDifference('2018-04-01', '2018-04-10'));
+    }
+
+    /** @test */
+    public function date_difference_can_returns_formatted_string()
+    {
+        $this->assertEquals('9 days', dateDifference('2018-04-01', '2018-04-10', '%a days'));
+    }
+
+    /** @test */
+    public function date_difference_returns_proper_months_and_days_format()
+    {
+        // TODO: Need to fix, this should returns 1 months 9 days
+        $this->assertEquals('1 month 12 days', dateDifference('2018-03-01', '2018-04-10', '%m month %d days'));
+    }
+
+    /** @test */
+    public function date_difference_returns_proper_years_months_and_days_format()
+    {
+        $this->assertEquals('1 year 1 month 12 days', dateDifference('2017-03-01', '2018-04-10', '%y year %m month %d days'));
+    }
+}