diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 751a4c1..cc1e9b7 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -11,8 +11,9 @@ taxonomy_permissions 7.x-1.1 (2016-07-27):
   - Add a dummy test that never fails, to keep d.o's testbot happy.
 
 taxonomy_permissions 7.x-1.0 (2015-06-11):
-  - #2022707: After two years and 513 known installations it's time to create a release (no functional change in this commit).
+  - #2022707: After two years and 513 known installations it's time to create a
+    release (no functional change in this commit).
 
 taxonomy_permissions 7.x-1.0-rc1 (2013-06-18):
-  - Initial commit of Taxonomy Permissions, a module to add more permissions to the Taxonomy core module.
-
+  - Initial commit of Taxonomy Permissions, a module to add more permissions to
+    the Taxonomy core module.
diff --git a/README.txt b/README.txt
index 2bb547e..3ccef73 100644
--- a/README.txt
+++ b/README.txt
@@ -59,4 +59,3 @@ For paid support and customizations of this module or other Drupal work
 contact the maintainer through his contact form:
 
    http://drupal.org/user/82964
-
diff --git a/src/TaxonomyPermissionsControlHandler.php b/src/TaxonomyPermissionsControlHandler.php
index 06f87f0..e512ce2 100644
--- a/src/TaxonomyPermissionsControlHandler.php
+++ b/src/TaxonomyPermissionsControlHandler.php
@@ -20,24 +20,49 @@ class TaxonomyPermissionsControlHandler extends EntityAccessControlHandler {
   protected function checkAccess(EntityInterface $entity, $operation, AccountInterface $account) {
     switch ($operation) {
       case 'view':
-        return AccessResult::allowedIfHasPermissions($account, ["view terms in {$entity->bundle()}", 'administer taxonomy'], 'OR');
-        break;
+
+        return AccessResult::allowedIfHasPermissions(
+            $account,
+            [
+              "view terms in {$entity->bundle()}",
+              'administer taxonomy',
+            ],
+            'OR');
 
       case 'create':
-        return AccessResult::allowedIfHasPermissions($account, ["create terms in {$entity->bundle()}", 'administer taxonomy'], 'OR');
-        break;
+
+        return AccessResult::allowedIfHasPermissions(
+            $account,
+            [
+              "create terms in {$entity->bundle()}",
+              'administer taxonomy',
+            ],
+            'OR');
 
       case 'update':
-        return AccessResult::allowedIfHasPermissions($account, ["edit terms in {$entity->bundle()}", 'administer taxonomy'], 'OR');
-        break;
+
+        return AccessResult::allowedIfHasPermissions(
+            $account,
+            [
+              "edit terms in {$entity->bundle()}",
+              'administer taxonomy',
+            ],
+            'OR');
 
       case 'delete':
-        return AccessResult::allowedIfHasPermissions($account, ["delete terms in {$entity->bundle()}", 'administer taxonomy'], 'OR');
-        break;
+
+        return AccessResult::allowedIfHasPermissions(
+            $account,
+            [
+              "delete terms in {$entity->bundle()}",
+              'administer taxonomy',
+            ],
+            'OR');
 
       default:
         // No opinion.
         return AccessResult::neutral();
+
     }
   }
 
diff --git a/src/Tests/TaxonomyPermissionsTestBase.php b/src/Tests/TaxonomyPermissionsTestBase.php
deleted file mode 100644
index b71d00d..0000000
--- a/src/Tests/TaxonomyPermissionsTestBase.php
+++ /dev/null
@@ -1,394 +0,0 @@
-<?php
-
-/**
- * @file
- * General setup and helper functions.
- */
-
-namespace Drupal\taxonomy_permissions\Tests;
-
-use Drupal\field\Entity\FieldConfig;
-use Drupal\field\Entity\FieldStorageConfig;
-use Drupal\Core\Entity\Entity\EntityFormDisplay;
-use Drupal\Core\Entity\Display\EntityFormDisplayInterface;
-use Drupal\Core\Entity\Entity\EntityViewDisplay;
-use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
-use Drupal\simpletest\WebTestBase;
-use Drupal\taxonomy\Tests\TaxonomyTestTrait;
-use Drupal\Core\Session\AccountInterface;
-use Drupal\taxonomy\VocabularyInterface;
-use Drupal\user\Entity\User;
-
-/**
- * General setup and helper function for testing taxonomy permissions module.
- *
- * @group taxonomy_permissions
- */
-class TaxonomyPermissionsTestBase extends WebTestBase {
-
-  use TaxonomyTestTrait;
-  /**
-   * Modules to install.
-   *
-   * @var array
-   */
-  public static $modules = array(
-    'system',
-    'user',
-    'node',
-    'field',
-    'field_ui',
-    'taxonomy',
-    'taxonomy_permissions',
-  );
-
-  /**
-   * Entity form display.
-   *
-   * @var \Drupal\Core\Entity\Display\EntityFormDisplayInterface
-   */
-  protected $formDisplay;
-
-  /**
-   * Entity view display.
-   *
-   * @var \Drupal\Core\Entity\Display\EntityViewDisplayInterface
-   */
-  protected $viewDisplay;
-
-  /**
-   * User with permission to view terms.
-   *
-   * @var \Drupal\user\UserInterface
-   */
-  protected $authorizedUser;
-
-  /**
-   * Basic User without permissions to view terms.
-   *
-   * @var \Drupal\user\UserInterface
-   */
-  protected $basicUser;
-
-  /**
-   * A node created.
-   *
-   * @var \Drupal\node\NodeInterface
-   */
-  protected $article1;
-
-  /**
-   * A node created.
-   *
-   * @var \Drupal\node\NodeInterface
-   */
-  protected $article2;
-
-  /**
-   * A vocabulary created.
-   *
-   * @var \Drupal\taxonomy\VocabularyInterface
-   */
-  protected $vocabulary;
-
-  /**
-   * A term created.
-   *
-   * @var \Drupal\taxonomy\TermInterface
-   */
-  protected $term1;
-
-  /**
-   * A term created.
-   *
-   * @var \Drupal\taxonomy\TermInterface
-   */
-  protected $term2;
-
-  /**
-   * Setup.
-   */
-  public function setUp() {
-    parent::setUp();
-
-    // Create vocabulary and terms.
-    $this->vocabulary = $this->createVocabulary();
-    $this->term1 = $this->createTerm($this->vocabulary);
-
-    // We remove standard permission provided by default.
-    $perms[] = 'view terms in ' . $this->vocabulary->id();
-    user_role_revoke_permissions(AccountInterface::ANONYMOUS_ROLE, $perms);
-    user_role_revoke_permissions(AccountInterface::AUTHENTICATED_ROLE, $perms);
-
-    $this->drupalCreateContentType(['type' => 'article']);
-
-    $this->authorizedUser = $this->drupalCreateUser([
-      'create article content',
-      'edit any article content',
-      'access content',
-      'view terms in ' . $this->vocabulary->id(),
-    ]);
-
-    $this->basicUser = $this->drupalCreateUser([
-      'create article content',
-      'edit any article content',
-      'access content',
-    ]);
-
-    $field_name = 'field_term';
-    $this->attachFields($field_name);
-
-    $this->article1 = $this->createSimpleArticle('Article 1', $field_name, $this->term1->id());
-  }
-
-  /**
-   * Tests if a user without permissions can view terms on node.
-   */
-  protected function testViewTerm() {
-
-    $this->drupalLogin($this->authorizedUser);
-    $this->drupalGet("node/{$this->article1->id()}");
-    $this->assertResponse(200);
-    $this->assertText($this->term1->getName());
-    $this->assertLink($this->term1->getName());
-
-    $this->drupalLogin($this->basicUser);
-    $this->drupalGet("node/{$this->article1->id()}");
-    $this->assertResponse(200);
-    $this->assertNoText($this->term1->getName());
-    $this->assertNoLink($this->term1->getName());
-  }
-
-  /**
-   * Tests if a user without permissions can access to term's page.
-   */
-  protected  function testAccessTermPage() {
-    $this->drupalLogin($this->authorizedUser);
-    $this->drupalGet("taxonomy/term/{$this->term1->id()}");
-    $this->assertResponse(200);
-
-    $this->drupalLogin($this->basicUser);
-    $this->drupalGet("taxonomy/term/{$this->term1->id()}");
-    $this->assertResponse(403);
-
-
-  }
-
-  /**
-   * Tests if a user without permissions can access to the field form.
-   */
-  protected  function testAccessFormTerm() {
-
-    $this->drupalLogin($this->authorizedUser);
-    $this->drupalGet("node/{$this->article1->id()}/edit");
-    $this->assertResponse(200);
-    $this->assertFieldByName('field_term[0][target_id]', $this->term1->getName() . ' (' . $this->term1->id() . ')', 'The expected value is found in the input field');
-
-    $this->drupalLogin($this->basicUser);
-    $this->drupalGet("node/{$this->article1->id()}/edit");
-    $this->assertResponse(200);
-    $this->assertNoFieldByName('field_term[0][target_id]', $this->term1->getName() . ' (' . $this->term1->id() . ')', 'The input field taxonomy reference is not accessible');
-
-  }
-
-  /**
-   * Creates a taxonomy term reference field on the specified bundle.
-   *
-   * @param string $entity_type
-   *   The type of entity the field will be attached to.
-   * @param string $bundle
-   *   The bundle name of the entity the field will be attached to.
-   * @param string $field_name
-   *   The name of the field; if it already exists, a new instance of existing
-   *   field will be created.
-   * @param string $field_label
-   *   The label of the field.
-   * @param string $target_entity_type
-   *   The type of the referenced entity.
-   * @param string $selection_handler
-   *   The selection handler used by this field.
-   * @param array $selection_handler_settings
-   *   An array of settings supported by the selection handler specified above.
-   *   (e.g. 'target_bundles', 'sort', 'auto_create', etc).
-   * @param int $cardinality
-   *   The cardinality of the field.
-   * @param string $user_method
-   *   The method used for granting access to user.
-   * @param int $priority
-   *   The priority access.
-   *
-   * @return \Drupal\field\Entity\FieldConfig $field
-   *   The field created or loaded.
-   *
-   * @see \Drupal\Core\Entity\Plugin\EntityReferenceSelection\SelectionBase::buildConfigurationForm()
-   */
-  protected function createField($entity_type, $bundle, $field_name, $field_label, $target_entity_type, $selection_handler = 'default', $selection_handler_settings = array(), $cardinality = 1, $user_method = 'user', $priority = 0) {
-    // Look for or add the specified field to the requested entity bundle.
-    if (!FieldStorageConfig::loadByName($entity_type, $field_name)) {
-      FieldStorageConfig::create(array(
-        'field_name' => $field_name,
-        'type' => 'entity_reference',
-        'entity_type' => $entity_type,
-        'cardinality' => $cardinality,
-        'settings' => array(
-          'target_type' => $target_entity_type,
-        ),
-      ))->save();
-    }
-    if (!FieldConfig::loadByName($entity_type, $bundle, $field_name)) {
-      FieldConfig::create(array(
-        'field_name' => $field_name,
-        'entity_type' => $entity_type,
-        'bundle' => $bundle,
-        'label' => $field_label,
-        'settings' => array(
-          'handler' => $selection_handler,
-          'handler_settings' => $selection_handler_settings,
-        ),
-      ))->save();
-    }
-    $field = FieldConfig::loadByName($entity_type, $bundle, $field_name);
-    return $field;
-  }
-
-  /**
-   * Set the widget for a component in a form display.
-   *
-   * @param string $form_display_id
-   *   The form display id.
-   * @param string $entity_type
-   *   The entity type name.
-   * @param string $bundle
-   *   The bundle name.
-   * @param string $field_name
-   *   The field name to set.
-   * @param string $widget_id
-   *   The widget id to set.
-   * @param array $settings
-   *   The settings of widget.
-   * @param string $mode
-   *   The mode name.
-   */
-  protected function setFormDisplay($form_display_id, $entity_type, $bundle, $field_name, $widget_id, $settings, $mode = 'default') {
-    // Set article's form display.
-    $this->formDisplay = EntityFormDisplay::load($form_display_id);
-
-    if (!$this->formDisplay) {
-      EntityFormDisplay::create([
-        'targetEntityType' => $entity_type,
-        'bundle' => $bundle,
-        'mode' => $mode,
-        'status' => TRUE,
-      ])->save();
-      $this->formDisplay = EntityFormDisplay::load($form_display_id);
-    }
-    if ($this->formDisplay instanceof EntityFormDisplayInterface) {
-      $this->formDisplay->setComponent($field_name, [
-        'type' => $widget_id,
-        'settings' => $settings,
-      ])->save();
-    }
-  }
-
-  /**
-   * Set the widget for a component in a View display.
-   *
-   * @param string $form_display_id
-   *   The form display id.
-   * @param string $entity_type
-   *   The entity type name.
-   * @param string $bundle
-   *   The bundle name.
-   * @param string $field_name
-   *   The field name to set.
-   * @param string $formatter_id
-   *   The formatter id to set.
-   * @param array $settings
-   *   The settings of widget.
-   * @param string $mode
-   *   The mode name.
-   */
-  protected function setViewDisplay($form_display_id, $entity_type, $bundle, $field_name, $formatter_id, $settings, $mode = 'default') {
-    // Set article's view display.
-    $this->viewDisplay = EntityViewDisplay::load($form_display_id);
-    if (!$this->viewDisplay) {
-      EntityViewDisplay::create([
-        'targetEntityType' => $entity_type,
-        'bundle' => $bundle,
-        'mode' => $mode,
-        'status' => TRUE,
-      ])->save();
-      $this->viewDisplay = EntityViewDisplay::load($form_display_id);
-    }
-    if ($this->viewDisplay instanceof EntityViewDisplayInterface) {
-      $this->viewDisplay->setComponent($field_name, [
-        'type' => $formatter_id,
-        'settings' => $settings,
-      ])->save();
-    }
-
-  }
-
-  /**
-   * Helper function to create and attach a field to a node.
-   *
-   * @param string $field_name
-   *   The field name to create and attach.
-   */
-  protected function attachFields($field_name) {
-    // Add a field to the article content type which reference term.
-    $handler_settings = array(
-      'target_bundles' => array(
-        $this->vocabulary->id() => $this->vocabulary->id(),
-      ),
-      'auto_create' => FALSE,
-    );
-
-    $this->createField('node', 'article', $field_name, 'Term referenced', 'taxonomy_term', 'default', $handler_settings);
-
-    // Set the form display.
-    $settings = [
-      'match_operator' => 'CONTAINS',
-      'size' => 30,
-      'placeholder' => '',
-    ];
-    $this->setFormDisplay('node.article.default', 'node', 'article', $field_name, 'entity_reference_autocomplete', $settings);
-
-    // Set the view display.
-    $settings = [
-      'link' => TRUE,
-    ];
-    $this->setViewDisplay('node.article.default', 'node', 'article', $field_name, 'entity_reference_label', $settings);
-
-  }
-
-  /**
-   * Create an article with value for field field_term.
-   *
-   * @param string $title
-   *   The content title.
-   * @param string $field_name
-   *   The Pbf field name to populate.
-   * @param int|string $target_id
-   *   The target id of taxonomy term.
-   *
-   * @return \Drupal\node\NodeInterface
-   *   The node created.
-   */
-  protected function createSimpleArticle($title, $field_name = '', $target_id = NULL) {
-    $values = array(
-      'type' => 'article',
-      'title' => $title,
-      'body' => [
-        'value' => 'Content body for ' . $title,
-      ],
-    );
-    if ($field_name) {
-      $values[$field_name] = [
-        'target_id' => $target_id,
-      ];
-    }
-    return $this->drupalCreateNode($values);
-  }
-
-}
diff --git a/taxonomy_permissions.install b/taxonomy_permissions.install
index ce31a4a..32ea774 100644
--- a/taxonomy_permissions.install
+++ b/taxonomy_permissions.install
@@ -10,11 +10,10 @@ use Drupal\taxonomy\Entity\Vocabulary;
 
 /**
  * Implements hook_install().
- *
- * Give 'view terms' access to all vocabularies to all users to avoid surprises
- * upon installation.
  */
 function taxonomy_permissions_install() {
+  // Give 'view terms' access to all vocabularies to all users to avoid
+  // surprises upon installation.
   $perms = [];
   $vocabularies = Vocabulary::loadMultiple();
   foreach ($vocabularies as $id => $vocabulary) {
diff --git a/tests/src/Functional/TaxonomyPermissionsTestBase.php b/tests/src/Functional/TaxonomyPermissionsTestBase.php
new file mode 100644
index 0000000..4224296
--- /dev/null
+++ b/tests/src/Functional/TaxonomyPermissionsTestBase.php
@@ -0,0 +1,382 @@
+<?php
+
+namespace Drupal\Tests\taxonomy_permissions\Functional;
+
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\Core\Entity\Entity\EntityFormDisplay;
+use Drupal\Core\Entity\Display\EntityFormDisplayInterface;
+use Drupal\Core\Entity\Entity\EntityViewDisplay;
+use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
+use Drupal\Tests\BrowserTestBase;
+use Drupal\taxonomy\Tests\TaxonomyTestTrait;
+use Drupal\Core\Session\AccountInterface;
+
+/**
+ * General setup and helper function for testing taxonomy permissions module.
+ *
+ * @group taxonomy_permissions
+ */
+class TaxonomyPermissionsTestBase extends BrowserTestBase {
+
+  use TaxonomyTestTrait;
+
+  /**
+   * Modules to install.
+   *
+   * @var array
+   */
+  public static $modules = [
+    'system',
+    'user',
+    'node',
+    'field',
+    'field_ui',
+    'taxonomy',
+    'taxonomy_permissions',
+  ];
+
+  /**
+   * Entity form display.
+   *
+   * @var \Drupal\Core\Entity\Display\EntityFormDisplayInterface
+   */
+  protected $formDisplay;
+
+  /**
+   * Entity view display.
+   *
+   * @var \Drupal\Core\Entity\Display\EntityViewDisplayInterface
+   */
+  protected $viewDisplay;
+
+  /**
+   * User with permission to view terms.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $authorizedUser;
+
+  /**
+   * Basic User without permissions to view terms.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $basicUser;
+
+  /**
+   * A node created.
+   *
+   * @var \Drupal\node\NodeInterface
+   */
+  protected $article1;
+
+  /**
+   * A node created.
+   *
+   * @var \Drupal\node\NodeInterface
+   */
+  protected $article2;
+
+  /**
+   * A vocabulary created.
+   *
+   * @var \Drupal\taxonomy\VocabularyInterface
+   */
+  protected $vocabulary;
+
+  /**
+   * A term created.
+   *
+   * @var \Drupal\taxonomy\TermInterface
+   */
+  protected $term1;
+
+  /**
+   * A term created.
+   *
+   * @var \Drupal\taxonomy\TermInterface
+   */
+  protected $term2;
+
+  /**
+   * Setup.
+   */
+  public function setUp() {
+    parent::setUp();
+
+    // Create vocabulary and terms.
+    $this->vocabulary = $this->createVocabulary();
+    $this->term1 = $this->createTerm($this->vocabulary);
+
+    // We remove standard permission provided by default.
+    $perms[] = 'view terms in ' . $this->vocabulary->id();
+    user_role_revoke_permissions(AccountInterface::ANONYMOUS_ROLE, $perms);
+    user_role_revoke_permissions(AccountInterface::AUTHENTICATED_ROLE, $perms);
+
+    $this->drupalCreateContentType(['type' => 'article']);
+
+    $this->authorizedUser = $this->drupalCreateUser([
+      'create article content',
+      'edit any article content',
+      'access content',
+      'view terms in ' . $this->vocabulary->id(),
+    ]);
+
+    $this->basicUser = $this->drupalCreateUser([
+      'create article content',
+      'edit any article content',
+      'access content',
+    ]);
+
+    $field_name = 'field_term';
+    $this->attachFields($field_name);
+
+    $this->article1 = $this->createSimpleArticle('Article 1', $field_name, $this->term1->id());
+  }
+
+  /**
+   * Tests if a user without permissions can view terms on node.
+   */
+  public function testViewTerm() {
+    $this->drupalLogin($this->authorizedUser);
+    $this->drupalGet("node/{$this->article1->id()}");
+    $this->assertResponse(200);
+    $this->assertText($this->term1->getName());
+    $this->assertLink($this->term1->getName());
+
+    $this->drupalLogin($this->basicUser);
+    $this->drupalGet("node/{$this->article1->id()}");
+    $this->assertResponse(200);
+    $this->assertNoText($this->term1->getName());
+    $this->assertNoLink($this->term1->getName());
+  }
+
+  /**
+   * Tests if a user without permissions can access to term's page.
+   */
+  public function testAccessTermPage() {
+    $this->drupalLogin($this->authorizedUser);
+    $this->drupalGet("taxonomy/term/{$this->term1->id()}");
+    $this->assertResponse(200);
+
+    $this->drupalLogin($this->basicUser);
+    $this->drupalGet("taxonomy/term/{$this->term1->id()}");
+    $this->assertResponse(403);
+  }
+
+  /**
+   * Tests if a user without permissions can access to the field form.
+   */
+  public function testAccessFormTerm() {
+    $this->drupalLogin($this->authorizedUser);
+    $this->drupalGet("node/{$this->article1->id()}/edit");
+    $this->assertResponse(200);
+    $this->assertFieldByName('field_term[0][target_id]', $this->term1->getName() . ' (' . $this->term1->id() . ')', 'The expected value is found in the input field');
+
+    $this->drupalLogin($this->basicUser);
+    $this->drupalGet("node/{$this->article1->id()}/edit");
+    $this->assertResponse(200);
+    $this->assertNoFieldByName('field_term[0][target_id]', $this->term1->getName() . ' (' . $this->term1->id() . ')', 'The input field taxonomy reference is not accessible');
+  }
+
+  /**
+   * Creates a taxonomy term reference field on the specified bundle.
+   *
+   * @param string $entity_type
+   *   The type of entity the field will be attached to.
+   * @param string $bundle
+   *   The bundle name of the entity the field will be attached to.
+   * @param string $field_name
+   *   The name of the field; if it already exists, a new instance of existing
+   *   field will be created.
+   * @param string $field_label
+   *   The label of the field.
+   * @param string $target_entity_type
+   *   The type of the referenced entity.
+   * @param string $selection_handler
+   *   The selection handler used by this field.
+   * @param array $selection_handler_settings
+   *   An array of settings supported by the selection handler specified above.
+   *   (e.g. 'target_bundles', 'sort', 'auto_create', etc).
+   * @param int $cardinality
+   *   The cardinality of the field.
+   * @param string $user_method
+   *   The method used for granting access to user.
+   * @param int $priority
+   *   The priority access.
+   *
+   * @return \Drupal\field\Entity\FieldConfig
+   *   The field created or loaded.
+   *
+   * @see \Drupal\Core\Entity\Plugin\EntityReferenceSelection\SelectionBase::buildConfigurationForm()
+   */
+  protected function createField($entity_type, $bundle, $field_name, $field_label, $target_entity_type, $selection_handler = 'default', array $selection_handler_settings = [], $cardinality = 1, $user_method = 'user', $priority = 0) {
+    // Look for or add the specified field to the requested entity bundle.
+    if (!FieldStorageConfig::loadByName($entity_type, $field_name)) {
+      FieldStorageConfig::create([
+        'field_name' => $field_name,
+        'type' => 'entity_reference',
+        'entity_type' => $entity_type,
+        'cardinality' => $cardinality,
+        'settings' => [
+          'target_type' => $target_entity_type,
+        ],
+      ])->save();
+    }
+    if (!FieldConfig::loadByName($entity_type, $bundle, $field_name)) {
+      FieldConfig::create([
+        'field_name' => $field_name,
+        'entity_type' => $entity_type,
+        'bundle' => $bundle,
+        'label' => $field_label,
+        'settings' => [
+          'handler' => $selection_handler,
+          'handler_settings' => $selection_handler_settings,
+        ],
+      ])->save();
+    }
+    $field = FieldConfig::loadByName($entity_type, $bundle, $field_name);
+    return $field;
+  }
+
+  /**
+   * Set the widget for a component in a form display.
+   *
+   * @param string $form_display_id
+   *   The form display id.
+   * @param string $entity_type
+   *   The entity type name.
+   * @param string $bundle
+   *   The bundle name.
+   * @param string $field_name
+   *   The field name to set.
+   * @param string $widget_id
+   *   The widget id to set.
+   * @param array $settings
+   *   The settings of widget.
+   * @param string $mode
+   *   The mode name.
+   */
+  protected function setFormDisplay($form_display_id, $entity_type, $bundle, $field_name, $widget_id, array $settings, $mode = 'default') {
+    // Set article's form display.
+    $this->formDisplay = EntityFormDisplay::load($form_display_id);
+
+    if (!$this->formDisplay) {
+      EntityFormDisplay::create([
+        'targetEntityType' => $entity_type,
+        'bundle' => $bundle,
+        'mode' => $mode,
+        'status' => TRUE,
+      ])->save();
+      $this->formDisplay = EntityFormDisplay::load($form_display_id);
+    }
+    if ($this->formDisplay instanceof EntityFormDisplayInterface) {
+      $this->formDisplay->setComponent($field_name, [
+        'type' => $widget_id,
+        'settings' => $settings,
+      ])->save();
+    }
+  }
+
+  /**
+   * Set the widget for a component in a View display.
+   *
+   * @param string $form_display_id
+   *   The form display id.
+   * @param string $entity_type
+   *   The entity type name.
+   * @param string $bundle
+   *   The bundle name.
+   * @param string $field_name
+   *   The field name to set.
+   * @param string $formatter_id
+   *   The formatter id to set.
+   * @param array $settings
+   *   The settings of widget.
+   * @param string $mode
+   *   The mode name.
+   */
+  protected function setViewDisplay($form_display_id, $entity_type, $bundle, $field_name, $formatter_id, array $settings, $mode = 'default') {
+    // Set article's view display.
+    $this->viewDisplay = EntityViewDisplay::load($form_display_id);
+    if (!$this->viewDisplay) {
+      EntityViewDisplay::create([
+        'targetEntityType' => $entity_type,
+        'bundle' => $bundle,
+        'mode' => $mode,
+        'status' => TRUE,
+      ])->save();
+      $this->viewDisplay = EntityViewDisplay::load($form_display_id);
+    }
+    if ($this->viewDisplay instanceof EntityViewDisplayInterface) {
+      $this->viewDisplay->setComponent($field_name, [
+        'type' => $formatter_id,
+        'settings' => $settings,
+      ])->save();
+    }
+  }
+
+  /**
+   * Helper function to create and attach a field to a node.
+   *
+   * @param string $field_name
+   *   The field name to create and attach.
+   */
+  protected function attachFields($field_name) {
+    // Add a field to the article content type which reference term.
+    $handler_settings = [
+      'target_bundles' => [
+        $this->vocabulary->id() => $this->vocabulary->id(),
+      ],
+      'auto_create' => FALSE,
+    ];
+
+    $this->createField('node', 'article', $field_name, 'Term referenced', 'taxonomy_term', 'default', $handler_settings);
+
+    // Set the form display.
+    $settings = [
+      'match_operator' => 'CONTAINS',
+      'size' => 30,
+      'placeholder' => '',
+    ];
+    $this->setFormDisplay('node.article.default', 'node', 'article', $field_name, 'entity_reference_autocomplete', $settings);
+
+    // Set the view display.
+    $settings = [
+      'link' => TRUE,
+    ];
+    $this->setViewDisplay('node.article.default', 'node', 'article', $field_name, 'entity_reference_label', $settings);
+
+  }
+
+  /**
+   * Create an article with value for field field_term.
+   *
+   * @param string $title
+   *   The content title.
+   * @param string $field_name
+   *   The Pbf field name to populate.
+   * @param int|string $target_id
+   *   The target id of taxonomy term.
+   *
+   * @return \Drupal\node\NodeInterface
+   *   The node created.
+   */
+  protected function createSimpleArticle($title, $field_name = '', $target_id = NULL) {
+    $values = [
+      'type' => 'article',
+      'title' => $title,
+      'body' => [
+        'value' => 'Content body for ' . $title,
+      ],
+    ];
+    if ($field_name) {
+      $values[$field_name] = [
+        'target_id' => $target_id,
+      ];
+    }
+    return $this->drupalCreateNode($values);
+  }
+
+}