diff --git a/core/modules/system/src/Tests/Entity/EntityFieldTest.php b/core/modules/system/src/Tests/Entity/EntityFieldTest.php
index 1fbf987..5d93c78 100644
--- a/core/modules/system/src/Tests/Entity/EntityFieldTest.php
+++ b/core/modules/system/src/Tests/Entity/EntityFieldTest.php
@@ -16,7 +16,6 @@
 use Drupal\Core\TypedData\DataDefinitionInterface;
 use Drupal\Core\TypedData\Type\StringInterface;
 use Drupal\Core\TypedData\TypedDataInterface;
-use Drupal\field\Entity\FieldStorageConfig;
 use Drupal\node\Entity\NodeType;
 
 /**
@@ -737,19 +736,4 @@ protected function doTestComputedProperties($entity_type) {
     $this->assertEqual($entity->field_test_text->processed, $target, format_string('%entity_type: Text is processed with the default filter.', array('%entity_type' => $entity_type)));
   }
 
-  /**
-   * Test saving single settings of a field.
-   */
-  public function testSetSettings() {
-    $field_storage = FieldStorageConfig::create(array(
-      'field_name' => 'test_field',
-      'entity_type' => 'entity_test',
-      'type' => 'test_field'
-    ));
-    $field_storage->save();
-    $settings = $field_storage->getSettings();
-    $settings['test_field_storage_setting'] = 'A valid test string';
-    $field_storage->setSettings(array('test_field_storage_setting' => 'A valid test string'));
-    $this->assertEqual($field_storage->getSettings(), $settings);
-  }
 }
diff --git a/core/modules/system/src/Tests/Field/FieldSettingsTest.php b/core/modules/system/src/Tests/Field/FieldSettingsTest.php
new file mode 100644
index 0000000..2c2a8e9
--- /dev/null
+++ b/core/modules/system/src/Tests/Field/FieldSettingsTest.php
@@ -0,0 +1,120 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\system\Tests\Field\FieldSettingsTest.
+ */
+
+namespace Drupal\system\Tests\Field;
+
+use Drupal\Core\Field\BaseFieldDefinition;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\system\Tests\Entity\EntityUnitTestBase;
+
+/**
+ * Tests field settings methods on field definition structures.
+ *
+ * @group Field
+ */
+class FieldSettingsTest extends EntityUnitTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('field', 'field_test');
+
+  /**
+   * @covers \Drupal\Core\Field\BaseFieldDefinition::getSettings()
+   * @covers \Drupal\Core\Field\BaseFieldDefinition::setSettings()
+   */
+  public function testBaseFieldSettings() {
+    $base_field = BaseFieldDefinition::create('test_field');
+
+    // Check that the default settings have been populated.
+    $expected_settings = [
+      'test_field_storage_setting' => 'dummy test string',
+      'changeable' => 'a changeable field storage setting',
+      'unchangeable' => 'an unchangeable field storage setting',
+      'translatable_storage_setting' => 'a translatable field storage setting',
+      'test_field_setting' => 'dummy test string',
+      'translatable_field_setting' => 'a translatable field setting',
+    ];
+    $this->assertEqual($base_field->getSettings(), $expected_settings);
+
+    // Change one single setting using setSettings(), and check that the other
+    // expected settings are still present.
+    $expected_settings['test_field_setting'] = 'another test string';
+    $base_field->setSettings(['test_field_setting' => $expected_settings['test_field_setting']]);
+    $this->assertEqual($base_field->getSettings(), $expected_settings);
+  }
+
+  /**
+   * @covers \Drupal\field\Entity\FieldStorageConfig::getSettings()
+   * @covers \Drupal\field\Entity\FieldStorageConfig::setSettings()
+   */
+  public function testConfigurableFieldStorageSettings() {
+    $field_storage = FieldStorageConfig::create([
+      'field_name' => 'test_field',
+      'entity_type' => 'entity_test',
+      'type' => 'test_field'
+    ]);
+
+    // Check that the default settings have been populated.
+    $expected_settings = [
+      'test_field_storage_setting' => 'dummy test string',
+      'changeable' => 'a changeable field storage setting',
+      'unchangeable' => 'an unchangeable field storage setting',
+      'translatable_storage_setting' => 'a translatable field storage setting',
+    ];
+    $this->assertEqual($field_storage->getSettings(), $expected_settings);
+
+    // Change one single setting using setSettings(), and check that the other
+    // expected settings are still present.
+    $expected_settings['test_field_storage_setting'] = 'another test string';
+    $field_storage->setSettings(['test_field_storage_setting' => $expected_settings['test_field_storage_setting']]);
+    $this->assertEqual($field_storage->getSettings(), $expected_settings);
+  }
+
+  /**
+   * @covers \Drupal\field\Entity\FieldStorageConfig::getSettings()
+   * @covers \Drupal\field\Entity\FieldStorageConfig::setSettings()
+   */
+  public function testConfigurableFieldSettings() {
+    $field_storage = FieldStorageConfig::create([
+      'field_name' => 'test_field',
+      'entity_type' => 'entity_test',
+      'type' => 'test_field'
+    ]);
+    $field = FieldConfig::create([
+      'field_storage' => $field_storage,
+      'bundle' => 'entity_test'
+    ]);
+    // Note: FieldConfig does not populate default settings until the config
+    // is saved.
+    // @todo Remove once https://www.drupal.org/node/2327883 is fixed.
+    $field->save();
+
+    // Check that the default settings have been populated. Note: getSettings()
+    // returns both storage and field settings.
+    $expected_settings = [
+      'test_field_storage_setting' => 'dummy test string',
+      'changeable' => 'a changeable field storage setting',
+      'unchangeable' => 'an unchangeable field storage setting',
+      'translatable_storage_setting' => 'a translatable field storage setting',
+      'test_field_setting' => 'dummy test string',
+      'translatable_field_setting' => 'a translatable field setting',
+      'field_setting_from_config_data' => TRUE,
+    ];
+    $this->assertEqual($field->getSettings(), $expected_settings);
+
+    // Change one single setting using setSettings(), and check that the other
+    // expected settings are still present.
+    $expected_settings['test_field_setting'] = 'another test string';
+    $field->setSettings(['test_field_setting' => $expected_settings['test_field_setting']]);
+    $this->assertEqual($field->getSettings(), $expected_settings);
+  }
+
+}