diff --git a/src/FocalPointEffectBase.php b/src/FocalPointEffectBase.php
index 96476a9..9bd9b15 100644
--- a/src/FocalPointEffectBase.php
+++ b/src/FocalPointEffectBase.php
@@ -49,13 +49,13 @@ abstract class FocalPointEffectBase extends ResizeImageEffect implements Contain
    *   Image logger.
    * @param \Drupal\crop\CropStorageInterface $crop_storage
    *   Crop storage.
-   * @param \Drupal\Core\Config\ImmutableConfig $config
+   * @param \Drupal\Core\Config\ImmutableConfig $focal_point_config
    *   Focal point configuration object.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, LoggerInterface $logger, CropStorageInterface $crop_storage, ImmutableConfig $config) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, LoggerInterface $logger, CropStorageInterface $crop_storage, ImmutableConfig $focal_point_config) {
     parent::__construct($configuration, $plugin_id, $plugin_definition, $logger);
     $this->cropStorage = $crop_storage;
-    $this->focalPointConfig = $config;
+    $this->focalPointConfig = $focal_point_config;
   }
 
   /**
@@ -73,9 +73,11 @@ abstract class FocalPointEffectBase extends ResizeImageEffect implements Contain
   }
 
   /**
-   * Calculate the resize dimensions of an image based on the longest crop
-   * dimension so that the aspect ratio is preserved and that there is always
-   * enough image available to the crop.
+   * Calculate the resize dimensions of an image.
+   *
+   * The calculated dimensions are based on the longest crop dimension (length
+   * or width) so that the aspect ratio is preserved in all cases and that there
+   * is always enough image available to the crop.
    *
    * @param int $image_width
    * @param int $image_height
@@ -122,11 +124,14 @@ abstract class FocalPointEffectBase extends ResizeImageEffect implements Contain
    */
   public function applyCrop(ImageInterface $image) {
     $crop_type = $this->focalPointConfig->get('crop_type');
+
     /** @var \Drupal\crop\CropInterface $crop */
     if ($crop = Crop::findCrop($image->getSource(), $crop_type)) {
+      // An existing crop has been found; set the size.
       $crop->setSize($this->configuration['width'], $this->configuration['height']);
     }
     else {
+      // No existing crop could be found; create a new one using the size.
       $crop = $this->cropStorage->create([
         'type' => $crop_type,
         'x' => (int) round($image->getWidth() / 2),
@@ -157,7 +162,7 @@ abstract class FocalPointEffectBase extends ResizeImageEffect implements Contain
   /**
    * Calculate the crop anchor.
    *
-   * This is based on Crop's anchor function with the additional logic to ensure
+   * This is based on Crop's anchor function with additional logic to ensure
    * that crop area doesn't fall outside of the original image.
    *
    * @param \Drupal\Core\Image\ImageInterface $image
@@ -175,19 +180,19 @@ abstract class FocalPointEffectBase extends ResizeImageEffect implements Contain
     // Set the minimum number of pixels that must exist between the edge of the
     // image and the anchor point (in both the x and y directions).
     $crop_size = $crop->size();
-    $crop_offset_x = (int)ceil($crop_size['width'] / 2);
-    $crop_offset_y = (int)ceil($crop_size['height'] / 2);
+    $anchor_min_margin_x = (int)ceil($crop_size['width'] / 2);
+    $anchor_min_margin_y = (int)ceil($crop_size['height'] / 2);
 
-    // Ensure that the crop area doesn't fall off the left or right side of the
+    // Ensure that the crop area doesn't fall off the left or right sides of the
     // image.
-    $left_bound = $crop_offset_x;
-    $right_bound = $image->getWidth() - $crop_offset_x;
+    $left_bound = $anchor_min_margin_x;
+    $right_bound = $image->getWidth() - $anchor_min_margin_x;
     $new_anchor['x'] = max(min($original_anchor['x'], $right_bound), $left_bound);
 
     // Ensure that the crop area doesn't fall off the top or bottom of the
     // image.
-    $top_bound = $crop_offset_y;
-    $bottom_bound = $image->getHeight() - $crop_offset_y;
+    $top_bound = $anchor_min_margin_y;
+    $bottom_bound = $image->getHeight() - $anchor_min_margin_y;
     $new_anchor['y'] = max(min($original_anchor['y'], $bottom_bound), $top_bound);
 
     return $new_anchor;
diff --git a/src/FocalPointManagerInterface.php b/src/FocalPointManagerInterface.php
index 2b40361..eedebbf 100644
--- a/src/FocalPointManagerInterface.php
+++ b/src/FocalPointManagerInterface.php
@@ -40,6 +40,8 @@ interface FocalPointManagerInterface {
    * @return array
    *   Array containing absolute coordinates of the focal point. 'x' and 'y' are
    *   used for array keys and corresponding coordinates as values.
+   *
+   * @see absoluteToRelative
    */
   public function relativeToAbsolute($x, $y, $width, $height);
 
@@ -58,6 +60,8 @@ interface FocalPointManagerInterface {
    * @return array
    *   Array containing relative coordinates of the focal point. 'x' and 'y' are
    *   used for array keys and corresponding coordinates as values.
+   *
+   * @see relativeToAbsolute
    */
   public function absoluteToRelative($x, $y, $width, $height);
 
diff --git a/src/Plugin/Field/FieldWidget/FocalPointImageWidget.php b/src/Plugin/Field/FieldWidget/FocalPointImageWidget.php
index 46a1955..5ee8830 100644
--- a/src/Plugin/Field/FieldWidget/FocalPointImageWidget.php
+++ b/src/Plugin/Field/FieldWidget/FocalPointImageWidget.php
@@ -7,9 +7,7 @@
 
 namespace Drupal\focal_point\Plugin\Field\FieldWidget;
 
-use Drupal\Core\Field\FieldDefinitionInterface;
-use Drupal\Core\Render\ElementInfoManagerInterface;
-use Drupal\Core\StringTranslation\TranslationTrait;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\crop\Entity\Crop;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\image\Plugin\Field\FieldWidget\ImageWidget;
@@ -69,7 +67,7 @@ class FocalPointImageWidget extends ImageWidget {
     $element['focal_point'] = array(
       '#type' => 'textfield',
       '#title' => 'Focal point',
-      '#description' => t('Specify the focus of this image in the form "leftoffset,topoffset" where offsets are in percents. Ex: 25,75'),
+      '#description' => new TranslatableMarkup('Specify the focus of this image in the form "leftoffset,topoffset" where offsets are in percents. Ex: 25,75'),
       '#default_value' => isset($item['focal_point']) ? $item['focal_point'] : \Drupal::config('focal_point.settings')->get('default_value'),
       '#element_validate' => array('\Drupal\focal_point\Plugin\Field\FieldWidget\FocalPointImageWidget::validateFocalPoint'),
       '#attributes' => array(
@@ -105,9 +103,9 @@ class FocalPointImageWidget extends ImageWidget {
       $crop_type = \Drupal::config('focal_point.settings')->get('crop_type');
       $crop = Crop::findCrop($file->getFileUri(), $crop_type);
       if ($crop) {
-        $coords = \Drupal::service('focal_point.manager')
+        $anchor = \Drupal::service('focal_point.manager')
           ->absoluteToRelative($crop->x->value, $crop->y->value, $return['width'], $return['height']);
-        $return['focal_point'] = "{$coords['x']},{$coords['y']}";
+        $return['focal_point'] = "{$anchor['x']},{$anchor['y']}";
       }
     }
     return $return;
@@ -123,7 +121,7 @@ class FocalPointImageWidget extends ImageWidget {
     $focal_point_value = $form_state->getValue($field_name);
 
     if (!is_null($focal_point_value) && \Drupal::service('focal_point.manager')->validateFocalPoint($focal_point_value)) {
-      $form_state->setError($element, \Drupal::translation()->translate('The !title field should be in the form "leftoffset,topoffset" where offsets are in percents. Ex: 25,75.', array('!title' => $element['#title'])));
+      $form_state->setError($element, new TranslatableMarkup('The !title field should be in the form "leftoffset,topoffset" where offsets are in percents. Ex: 25,75.', array('!title' => $element['#title'])));
     }
   }
 
diff --git a/tests/src/Unit/FocalPointTest.php b/tests/src/Unit/FocalPointTest.php
index bef47f7..ff96c7b 100644
--- a/tests/src/Unit/FocalPointTest.php
+++ b/tests/src/Unit/FocalPointTest.php
@@ -7,11 +7,15 @@
 
 namespace Drupal\Tests\focal_point\Unit;
 
+use Drupal\crop\CropStorageInterface;
+use Drupal\Core\Entity\EntityTypeManager;
+use Symfony\Component\DependencyInjection\ContainerInterface;
 use Drupal\focal_point\FocalPointManager;
 use Drupal\Tests\UnitTestCase;
 
 /**
  * @coversDefaultClass \Drupal\focal_point\FocalPointManager
+ *
  * @group Focal Point
  */
 class FocalPointTest extends UnitTestCase {
@@ -28,30 +32,21 @@ class FocalPointTest extends UnitTestCase {
    */
   protected function setUp() {
     parent::setUp();
-    $crop_storage = $this->getMockBuilder('Drupal\crop\CropStorage')
-      ->disableOriginalConstructor()
-      ->getMock();
-    $entity_type_manager = $this->getMockBuilder('Drupal\Core\Entity\EntityTypeManager')
-      ->disableOriginalConstructor()
-      ->getMock();
-    $entity_type_manager->expects($this->any())
-      ->method('getStorage')
-      ->with('crop')
-      ->will($this->returnValue($crop_storage));
-
-    $container = $this->getMock('Symfony\Component\DependencyInjection\ContainerInterface');
-    $container->expects($this->any())
-      ->method('get')
-      ->with('entity_type.manager')
-      ->will($this->returnValue($entity_type_manager));
-
-    \Drupal::setContainer($container);
+    $crop_storage = $this->prophesize(CropStorageInterface::class);
+
+    $entity_type_manager = $this->prophesize(EntityTypeManager::class);
+    $entity_type_manager->getStorage('crop')->willReturn($crop_storage);
+
+    $container = $this->prophesize(ContainerInterface::class);
+    $container->get('entity_type.manager')->willReturn($entity_type_manager);
+
+    \Drupal::setContainer($container->reveal());
 
     $this->focalPointManager = new FocalPointManager(\Drupal::service('entity_type.manager'));
   }
 
   /**
-   * Tests the validateFocalPoint() method.
+   * @covers ::validateFocalPoint
    *
    * @dataProvider providerValidateFocalPoint
    */
@@ -63,25 +58,31 @@ class FocalPointTest extends UnitTestCase {
    * Data provider for testFocalPoint().
    */
   public function providerValidateFocalPoint() {
-    return [
-      ['50,50', TRUE],
-      ['75,25', TRUE],
-      ['3,50', TRUE],
-      ['83,6', TRUE],
-      ['2,9', TRUE],
-      ['100,100', TRUE],
-      ['0,0', TRUE],
-      ['100,0', TRUE],
-      ['-20,50', FALSE],
-      ['18,-3', FALSE],
-      ['44,101', FALSE],
-      ['', FALSE],
-      ['invalid', FALSE],
-    ];
+    $data = [];
+    $data['default_focal_point_position'] = ['50,50', TRUE];
+    $data['basic_focal_point_position_1'] = ['75,25', TRUE];
+    $data['basic_focal_point_position_2'] = ['3,50', TRUE];
+    $data['basic_focal_point_position_3'] = ['83,6', TRUE];
+    $data['basic_focal_point_position_4'] = ['2,9', TRUE];
+    $data['extreme_focal_point_position_top_right'] = ['100,0', TRUE];
+    $data['extreme_focal_point_position_top_left'] = ['0,0', TRUE];
+    $data['extreme_focal_point_position_bottom_right'] = ['100,100', TRUE];
+    $data['extreme_focal_point_position_bottom_left'] = ['0,100', TRUE];
+    $data['invalid_focal_point_position_negative_x'] = ['-20,50', FALSE];
+    $data['invalid_focal_point_position_negative_y'] = ['18,-3', FALSE];
+    $data['invalid_focal_point_position_out_of_bounds_x'] = ['101,33', FALSE];
+    $data['invalid_focal_point_position_out_of_bounds_y'] = ['44,101', FALSE];
+    $data['invalid_focal_point_position_out_of_bounds_xy'] = ['313,512', FALSE];
+    $data['invalid_focal_point_position_empty'] = ['', FALSE];
+    $data['invalid_focal_point_position_incorrect_format_1'] = ['invalid', FALSE];
+    $data['invalid_focal_point_position_incorrect_format_2'] = ['invalid,invalid', FALSE];
+    $data['invalid_focal_point_position_incorrect_format_3'] = ['23,invalid', FALSE];
+
+    return $data;
   }
 
   /**
-   * Tests the relativeToAbsolute() method.
+   * @covers ::relativeToAbsolute
    *
    * @dataProvider providerCoordinates
    */
@@ -94,7 +95,7 @@ class FocalPointTest extends UnitTestCase {
   }
 
   /**
-   * Tests the absoluteToRelative() method.
+   * @covers ::absoluteToRelative
    *
    * @dataProvider providerCoordinates
    */
@@ -110,43 +111,44 @@ class FocalPointTest extends UnitTestCase {
    * Data provider for testRelativeToAbsolute() and absoluteToRelative().
    */
   public function providerCoordinates() {
-    return [
-      [
-        ['x' => 0, 'y' => 0],
-        ['width' => 1000, 'height' => 2000],
-        ['x' => 0, 'y' => 0]
-      ],
-      [
-        ['x' => 25, 'y' => 50],
-        ['width' => 1000, 'height' => 2000],
-        ['x' => 250, 'y' => 1000]
-      ],
-      [
-        ['x' => 50, 'y' => 25],
-        ['width' => 1000, 'height' => 2000],
-        ['x' => 500, 'y' => 500]
-      ],
-      [
-        ['x' => 50, 'y' => 50],
-        ['width' => 1000, 'height' => 2000],
-        ['x' => 500, 'y' => 1000]
-      ],
-      [
-        ['x' => 75, 'y' => 50],
-        ['width' => 1000, 'height' => 2000],
-        ['x' => 750, 'y' => 1000]
-      ],
-      [
-        ['x' => 100, 'y' => 75],
-        ['width' => 1000, 'height' => 2000],
-        ['x' => 1000, 'y' => 1500]
-      ],
-      [
-        ['x' => 100, 'y' => 100],
-        ['width' => 1000, 'height' => 2000],
-        ['x' => 1000, 'y' => 2000]
-      ],
+    $data = [];
+    $data['top_left'] = [
+      ['x' => 0, 'y' => 0],
+      ['width' => 1000, 'height' => 2000],
+      ['x' => 0, 'y' => 0],
+    ];
+    $data['basic_case_1'] = [
+      ['x' => 25, 'y' => 50],
+      ['width' => 1000, 'height' => 2000],
+      ['x' => 250, 'y' => 1000]
     ];
+    $data['basic_case_2'] = [
+      ['x' => 50, 'y' => 25],
+      ['width' => 1000, 'height' => 2000],
+      ['x' => 500, 'y' => 500],
+    ];
+    $data['basic_case_3'] = [
+      ['x' => 50, 'y' => 50],
+      ['width' => 1000, 'height' => 2000],
+      ['x' => 500, 'y' => 1000],
+    ];
+    $data['basic_case_4'] = [
+      ['x' => 75, 'y' => 50],
+      ['width' => 1000, 'height' => 2000],
+      ['x' => 750, 'y' => 1000],
+    ];
+    $data['basic_case_5'] = [
+      ['x' => 100, 'y' => 75],
+      ['width' => 1000, 'height' => 2000],
+      ['x' => 1000, 'y' => 1500],
+    ];
+    $data['bottom_right'] = [
+      ['x' => 100, 'y' => 100],
+      ['width' => 1000, 'height' => 2000],
+      ['x' => 1000, 'y' => 2000],
+    ];
+
+    return $data;
   }
 
 }