diff --git a/src/Plugin/facets/query_type/SearchApiDate.php b/src/Plugin/facets/query_type/SearchApiDate.php
index a89a45d..b4cf325 100644
--- a/src/Plugin/facets/query_type/SearchApiDate.php
+++ b/src/Plugin/facets/query_type/SearchApiDate.php
@@ -24,13 +24,33 @@ use Drupal\facets\QueryType\QueryTypeRangeBase;
 class SearchApiDate extends QueryTypeRangeBase {
 
   /**
-   * Granularity constants for grouping results.
+   * Constant for grouping on year.
    */
   const FACETAPI_DATE_YEAR = 6;
+
+  /**
+   * Constant for grouping on month.
+   */
   const FACETAPI_DATE_MONTH = 5;
+
+  /**
+   * Constant for grouping on day.
+   */
   const FACETAPI_DATE_DAY = 4;
+
+  /**
+   * Constant for grouping on hour.
+   */
   const FACETAPI_DATE_HOUR = 3;
+
+  /**
+   * Constant for grouping on minute.
+   */
   const FACETAPI_DATE_MINUTE = 2;
+
+  /**
+   * Constant for grouping on second.
+   */
   const FACETAPI_DATE_SECOND = 1;
 
   /**
@@ -45,33 +65,55 @@ class SearchApiDate extends QueryTypeRangeBase {
     }
   }
 
+  /**
+   * Returns a start and end date based on a unix timestamp.
+   *
+   * This method returns a start and end date with an absolute interval, based
+   * on the granularity set in the widget.
+   *
+   * @param int $value
+   *   Unix timestamp.
+   *
+   * @return array
+   *   An array with a start and end date as unix timestamps.
+   *
+   * @throws \Exception
+   *   Thrown when creating a date fails.
+   */
   protected function calculateRangeAbsolute($value) {
     $dateTime = new DrupalDateTime();
+
     switch ($this->getGranularity()) {
       case static::FACETAPI_DATE_YEAR:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . '1-1T00:00:00');
         $stopDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . '12-3123:59:59');
         break;
+
       case static::FACETAPI_DATE_MONTH:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . '-1T00:00:00');
         $stopDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . '-31T23:59:59');
         break;
+
       case static::FACETAPI_DATE_DAY:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . 'T00:00:00');
         $stopDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . 'T23:59:59');
         break;
+
       case static::FACETAPI_DATE_HOUR:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . '00:00');
         $stopDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . '59:59');
         break;
+
       case static::FACETAPI_DATE_MINUTE:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . ':00');
         $stopDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . ':59');
         break;
+
       case static::FACETAPI_DATE_SECOND:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value);
         $stopDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value);
         break;
+
     }
 
     return [
@@ -80,8 +122,24 @@ class SearchApiDate extends QueryTypeRangeBase {
     ];
   }
 
+  /**
+   * Returns a start and end date based on a unix timestamp.
+   *
+   * This method returns a start and end date with an relative interval, based
+   * on the granularity set in the widget.
+   *
+   * @param int $value
+   *   Unix timestamp.
+   *
+   * @return array
+   *   An array with a start and end date as unix timestamps.
+   *
+   * @throws \Exception
+   *   Thrown when creating a date fails.
+   */
   protected function calculateRangeRelative($value) {
     $dateTime = new DrupalDateTime();
+
     switch ($this->getGranularity()) {
       case static::FACETAPI_DATE_YEAR:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . '-1T00:00:00');
@@ -89,34 +147,40 @@ class SearchApiDate extends QueryTypeRangeBase {
         $stopDate->add(new \DateInterval('P1Y'));
         $stopDate->sub(new \DateInterval('PT1S'));
         break;
+
       case static::FACETAPI_DATE_MONTH:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . 'T00:00:00');
         $stopDate = clone $startDate;
         $stopDate->add(new \DateInterval('P1M'));
         $stopDate->sub(new \DateInterval('PT1S'));
         break;
+
       case static::FACETAPI_DATE_DAY:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . ':00:00');
         $stopDate = clone $startDate;
         $stopDate->add(new \DateInterval('P1D'));
         $stopDate->sub(new \DateInterval('PT1S'));
         break;
+
       case static::FACETAPI_DATE_HOUR:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value . ':00');
         $stopDate = clone $startDate;
         $stopDate->add(new \DateInterval('PT1H'));
         $stopDate->sub(new \DateInterval('PT1S'));
         break;
+
       case static::FACETAPI_DATE_MINUTE:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value);
         $stopDate = clone $startDate;
         $stopDate->add(new \DateInterval('PT1M'));
         $stopDate->sub(new \DateInterval('PT1S'));
         break;
+
       case static::FACETAPI_DATE_SECOND:
         $startDate = $dateTime::createFromFormat('Y-m-d\TH:i:s', $value);
         $stopDate = clone $startDate;
         break;
+
     }
 
     return [
@@ -125,7 +189,15 @@ class SearchApiDate extends QueryTypeRangeBase {
     ];
   }
 
-
+  /**
+   * Calculates the result of the filter.
+   *
+   * @param int $value
+   *   A unix timestamp.
+   *
+   * @return array
+   *   An array with a start and end date as unix timestamps.
+   */
   public function calculateResultFilter($value) {
     if ($this->getDisplayRelative()) {
       return $this->calculateResultFilterRelative($value);
@@ -142,31 +214,38 @@ class SearchApiDate extends QueryTypeRangeBase {
     $date = new DrupalDateTime();
     $date->setTimestamp($value);
     $date_display = $this->getDateFormat();
+
     switch ($this->getGranularity()) {
       case static::FACETAPI_DATE_YEAR:
         $format = 'Y';
         $raw = $date->format('Y');
         break;
+
       case static::FACETAPI_DATE_MONTH:
         $format = 'F Y';
         $raw = $date->format('Y-m');
         break;
+
       case static::FACETAPI_DATE_DAY:
         $format = 'd F Y';
         $raw = $date->format('Y-m-d');
         break;
+
       case static::FACETAPI_DATE_HOUR:
         $format = 'd/m/Y H\h';
         $raw = $date->format('Y-m-d\TH');
         break;
+
       case static::FACETAPI_DATE_MINUTE:
         $format = 'd/m/Y H:i';
         $raw = $date->format('Y-m-d\TH:i');
         break;
+
       case static::FACETAPI_DATE_SECOND:
         $format = 'd/m/Y H:i:s';
         $raw = $date->format('Y-m-d\TH:i:s');
         break;
+
     }
     $format = $date_display ? $date_display : $format;
     return [
@@ -200,6 +279,7 @@ class SearchApiDate extends QueryTypeRangeBase {
         }
         $raw = $now->format('Y-m');
         break;
+
       case static::FACETAPI_DATE_MONTH:
         $rounded = new \DateInterval('P' . $interval->y . 'Y' . $interval->m . 'M');
         $display = $interval->y ? $this->formatPlural($interval->y, '1 year', '@count years') . ' ' : '';
@@ -218,6 +298,7 @@ class SearchApiDate extends QueryTypeRangeBase {
         }
         $raw = $now->format('Y-m-d');
         break;
+
       case static::FACETAPI_DATE_DAY:
         $rounded = new \DateInterval('P' . $interval->y . 'Y' . $interval->m . 'M' . $interval->d . 'D');
         $display = $interval->y ? $this->formatPlural($interval->y, '1 year', '@count years') . ' ' : '';
@@ -237,6 +318,7 @@ class SearchApiDate extends QueryTypeRangeBase {
         }
         $raw = $now->format('Y-m-d\TH');
         break;
+
       case static::FACETAPI_DATE_HOUR:
         $rounded = new \DateInterval('P' . $interval->y . 'Y' . $interval->m . 'M' . $interval->d . 'DT' . $interval->h . 'H');
         $display = $interval->y ? $this->formatPlural($interval->y, '1 year', '@count years') . ' ' : '';
@@ -257,6 +339,7 @@ class SearchApiDate extends QueryTypeRangeBase {
         }
         $raw = $now->format('Y-m-d\TH:i');
         break;
+
       case static::FACETAPI_DATE_MINUTE:
         $rounded = new \DateInterval('P' . $interval->y . 'Y' . $interval->m . 'M' . $interval->d . 'DT' . $interval->h . 'H' . $interval->i);
         $display = $interval->y ? $this->formatPlural($interval->y, '1 year', '@count years') . ' ' : '';
@@ -278,6 +361,7 @@ class SearchApiDate extends QueryTypeRangeBase {
         }
         $raw = $date->format('Y-m-d\TH:i:s');
         break;
+
       case static::FACETAPI_DATE_SECOND:
         $rounded = new \DateInterval('P' . $interval->y . 'Y' . $interval->m . 'M' . $interval->d . 'DT' . $interval->h . 'H' . $interval->i . $interval->s . 'S');
         $display = $interval->y ? $this->formatPlural($interval->y, '1 year', '@count years') . ' ' : '';
@@ -300,7 +384,9 @@ class SearchApiDate extends QueryTypeRangeBase {
         }
         $raw = $date->format('Y-m-d\TH:i:s');
         break;
+
     }
+
     return [
       'display' => $display,
       'raw' => $raw,
diff --git a/src/Plugin/facets/widget/DateBasicWidget.php b/src/Plugin/facets/widget/DateBasicWidget.php
index a984ba1..32c1b20 100644
--- a/src/Plugin/facets/widget/DateBasicWidget.php
+++ b/src/Plugin/facets/widget/DateBasicWidget.php
@@ -8,7 +8,6 @@ use Drupal\facets\Result\Result;
 use Drupal\facets\Widget\WidgetPluginBase;
 use Drupal\facets\Plugin\facets\query_type\SearchApiDate;
 
-
 /**
  * Basic date widget.
  *
@@ -24,6 +23,7 @@ class DateBasicWidget extends WidgetPluginBase {
    * Human readable array of granularity options.
    *
    * @return array
+   *   An array of granularity options.
    */
   private function granularityOptions() {
     return array(
@@ -36,7 +36,6 @@ class DateBasicWidget extends WidgetPluginBase {
     );
   }
 
-
   /**
    * {@inheritdoc}
    */
@@ -120,4 +119,5 @@ class DateBasicWidget extends WidgetPluginBase {
       ],
     ];
   }
+
 }
diff --git a/src/Plugin/facets/widget/NumericGranularWidget.php b/src/Plugin/facets/widget/NumericGranularWidget.php
index f5439fc..6158437 100644
--- a/src/Plugin/facets/widget/NumericGranularWidget.php
+++ b/src/Plugin/facets/widget/NumericGranularWidget.php
@@ -4,10 +4,6 @@ namespace Drupal\facets\Plugin\facets\widget;
 
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\facets\FacetInterface;
-use Drupal\facets\Result\Result;
-use Drupal\facets\Widget\WidgetPluginBase;
-use Drupal\facets\Plugin\facets\query_type\SearchApiDate;
-
 
 /**
  * Basic granular widget.
diff --git a/tests/src/Unit/Plugin/query_type/SearchApiDateTest.php b/tests/src/Unit/Plugin/query_type/SearchApiDateTest.php
index 126f364..bf79636 100644
--- a/tests/src/Unit/Plugin/query_type/SearchApiDateTest.php
+++ b/tests/src/Unit/Plugin/query_type/SearchApiDateTest.php
@@ -14,6 +14,9 @@ use Drupal\search_api\Plugin\views\query\SearchApiQuery;
  */
 class SearchApiDateTest extends KernelTestBase {
 
+  /**
+   * {@inheritdoc}
+   */
   public function setUp() {
     parent::setUp();
 
@@ -30,7 +33,7 @@ class SearchApiDateTest extends KernelTestBase {
    */
   public function testQueryTypeAnd($granularity, $original_results, $grouped_results) {
     $query = new SearchApiQuery([], 'search_api_query', []);
-    $facetReflection = new \ReflectionClass ('Drupal\facets\Entity\Facet');
+    $facetReflection = new \ReflectionClass('Drupal\facets\Entity\Facet');
     $facet = new Facet(
       ['query_operator' => 'AND'],
       'facets_facet'
diff --git a/tests/src/Unit/Plugin/query_type/SearchApiGranularTest.php b/tests/src/Unit/Plugin/query_type/SearchApiGranularTest.php
index 4157247..7a5f916 100644
--- a/tests/src/Unit/Plugin/query_type/SearchApiGranularTest.php
+++ b/tests/src/Unit/Plugin/query_type/SearchApiGranularTest.php
@@ -19,7 +19,7 @@ class SearchApiGranularTest extends UnitTestCase {
    */
   public function testQueryTypeAnd() {
     $query = new SearchApiQuery([], 'search_api_query', []);
-    $facetReflection = new \ReflectionClass ('Drupal\facets\Entity\Facet');
+    $facetReflection = new \ReflectionClass('Drupal\facets\Entity\Facet');
     $facet = new Facet(
       ['query_operator' => 'AND'],
       'facets_facet'