diff --git a/composer.json b/composer.json
index 03282fc..5240f99 100644
--- a/composer.json
+++ b/composer.json
@@ -2,7 +2,7 @@
     "name": "meritoo/common-library",
     "description": "Useful classes, methods, extensions etc.",
     "license": "MIT",
-    "version": "0.0.17",
+    "version": "0.0.18",
     "authors": [
         {
             "name": "Meritoo.pl",
diff --git a/src/Utilities/DatePeriod.php b/src/Type/DatePeriod.php
similarity index 91%
rename from src/Utilities/DatePeriod.php
rename to src/Type/DatePeriod.php
index 3a87d73..07c2b88 100644
--- a/src/Utilities/DatePeriod.php
+++ b/src/Type/DatePeriod.php
@@ -6,9 +6,11 @@
  * file that was distributed with this source code.
  */
 
-namespace Meritoo\Common\Utilities;
+namespace Meritoo\Common\Type;
 
 use DateTime;
+use Meritoo\Common\Type\Base\BaseType;
+use Meritoo\Common\Utilities\Date;
 
 /**
  * A date's period.
@@ -17,7 +19,7 @@ use DateTime;
  * @author    Krzysztof Niziol <krzysztof.niziol@meritoo.pl>
  * @copyright Meritoo.pl
  */
-class DatePeriod
+class DatePeriod extends BaseType
 {
     /**
      * The period constant: last month
@@ -108,17 +110,6 @@ class DatePeriod
         $this->endDate = $endDate;
     }
 
-    /**
-     * Returns information if given period is correct
-     *
-     * @param int $period The period to verify
-     * @return bool
-     */
-    public static function isCorrectPeriod($period)
-    {
-        return in_array($period, Reflection::getConstants(__CLASS__));
-    }
-
     /**
      * Returns formatted one of the period's date: start date or end date
      *
diff --git a/src/Utilities/Date.php b/src/Utilities/Date.php
index 8964691..2e95054 100644
--- a/src/Utilities/Date.php
+++ b/src/Utilities/Date.php
@@ -12,6 +12,7 @@ use DateInterval;
 use DateTime;
 use Meritoo\Common\Exception\Date\UnknownDatePartTypeException;
 use Meritoo\Common\Type\DatePartType;
+use Meritoo\Common\Type\DatePeriod;
 
 /**
  * Useful date methods
@@ -72,7 +73,7 @@ class Date
     {
         $datePeriod = null;
 
-        if (DatePeriod::isCorrectPeriod($period)) {
+        if ((new DatePeriod())->isCorrectType($period)) {
             $dateStart = null;
             $dateEnd = null;
 
diff --git a/tests/Utilities/DatePeriodTest.php b/tests/Type/DatePeriodTest.php
similarity index 78%
rename from tests/Utilities/DatePeriodTest.php
rename to tests/Type/DatePeriodTest.php
index ba5a06b..52e1924 100644
--- a/tests/Utilities/DatePeriodTest.php
+++ b/tests/Type/DatePeriodTest.php
@@ -6,13 +6,13 @@
  * file that was distributed with this source code.
  */
 
-namespace Meritoo\Common\Test\Utilities;
+namespace Meritoo\Common\Test\Type;
 
 use DateTime;
 use Generator;
-use Meritoo\Common\Test\Base\BaseTestCase;
+use Meritoo\Common\Test\Base\BaseTypeTestCase;
+use Meritoo\Common\Type\DatePeriod;
 use Meritoo\Common\Type\OopVisibilityType;
-use Meritoo\Common\Utilities\DatePeriod;
 
 /**
  * Test case of date's period
@@ -20,7 +20,7 @@ use Meritoo\Common\Utilities\DatePeriod;
  * @author    Krzysztof Niziol <krzysztof.niziol@meritoo.pl>
  * @copyright Meritoo.pl
  */
-class DatePeriodTest extends BaseTestCase
+class DatePeriodTest extends BaseTypeTestCase
 {
     public function testConstructorVisibilityAndArguments()
     {
@@ -58,33 +58,6 @@ class DatePeriodTest extends BaseTestCase
         self::assertEquals($endDate, $period->getEndDate());
     }
 
-    /**
-     * @param mixed $period Empty value, e.g. ""
-     * @dataProvider provideEmptyValue
-     */
-    public function testIsCorrectPeriodEmptyPeriod($period)
-    {
-        self::assertFalse(DatePeriod::isCorrectPeriod($period));
-    }
-
-    /**
-     * @param int $period Incorrect period to verify
-     * @dataProvider provideIncorrectPeriod
-     */
-    public function testIsCorrectPeriodIncorrectPeriod($period)
-    {
-        self::assertFalse(DatePeriod::isCorrectPeriod($period));
-    }
-
-    /**
-     * @param int $period The period to verify
-     * @dataProvider providePeriod
-     */
-    public function testIsCorrectPeriod($period)
-    {
-        self::assertTrue(DatePeriod::isCorrectPeriod($period));
-    }
-
     /**
      * @param DatePeriod $period The date period to verify
      * @param string     $format Format used to format the date
@@ -142,36 +115,6 @@ class DatePeriodTest extends BaseTestCase
         ];
     }
 
-    /**
-     * Provides incorrect period
-     *
-     * @return Generator
-     */
-    public function provideIncorrectPeriod()
-    {
-        yield[-1];
-        yield[0];
-        yield[10];
-    }
-
-    /**
-     * Provides period to verify
-     *
-     * @return Generator
-     */
-    public function providePeriod()
-    {
-        yield[DatePeriod::LAST_WEEK];
-        yield[DatePeriod::THIS_WEEK];
-        yield[DatePeriod::NEXT_WEEK];
-        yield[DatePeriod::LAST_MONTH];
-        yield[DatePeriod::THIS_MONTH];
-        yield[DatePeriod::NEXT_MONTH];
-        yield[DatePeriod::LAST_YEAR];
-        yield[DatePeriod::THIS_YEAR];
-        yield[DatePeriod::NEXT_YEAR];
-    }
-
     /**
      * Provides period and incorrect format of date to verify
      *
@@ -270,4 +213,68 @@ class DatePeriodTest extends BaseTestCase
             '2002-02-02 00:00',
         ];
     }
+
+    /**
+     * Returns all expected types of the tested type
+     *
+     * @return array
+     */
+    protected function getAllExpectedTypes()
+    {
+        return [
+            'LAST_MONTH' => DatePeriod::LAST_MONTH,
+            'LAST_WEEK'  => DatePeriod::LAST_WEEK,
+            'LAST_YEAR'  => DatePeriod::LAST_YEAR,
+            'NEXT_MONTH' => DatePeriod::NEXT_MONTH,
+            'NEXT_WEEK'  => DatePeriod::NEXT_WEEK,
+            'NEXT_YEAR'  => DatePeriod::NEXT_YEAR,
+            'THIS_MONTH' => DatePeriod::THIS_MONTH,
+            'THIS_WEEK'  => DatePeriod::THIS_WEEK,
+            'THIS_YEAR'  => DatePeriod::THIS_YEAR,
+        ];
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getTestedTypeInstance()
+    {
+        return new DatePeriod();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function provideTypeToVerify()
+    {
+        yield[
+            '',
+            false,
+        ];
+
+        yield[
+            -1,
+            false,
+        ];
+
+        yield[
+            true,
+            false,
+        ];
+
+        yield[
+            DatePeriod::LAST_MONTH,
+            true,
+        ];
+
+        yield[
+            DatePeriod::NEXT_WEEK,
+            true,
+        ];
+
+        yield[
+            DatePeriod::THIS_YEAR,
+            true,
+        ];
+    }
 }