diff --git a/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php b/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php
index d62412b..8a3244d 100644
--- a/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php
+++ b/core/modules/field/lib/Drupal/field/Tests/FieldInfoTest.php
@@ -263,4 +263,29 @@ class FieldInfoTest extends FieldTestBase {
       $this->assertIdentical(field_info_formatter_settings($type), $data['settings'], "field_info_formatter_settings returns {$type}'s formatter settings");
     }
   }
+
+  /**
+   * Tests that the field info cache can be built correctly.
+   */
+  function testFieldInfoCache() {
+    // Create a test field and ensure it's in the array returned by
+    // field_info_fields().
+    $field_name = drupal_strtolower($this->randomName());
+    $field = array(
+      'field_name' => $field_name,
+      'type' => 'test_field',
+    );
+    field_create_field($field);
+    $fields = field_info_fields();
+    $this->assertTrue(isset($fields[$field_name]), 'The test field is initially found in the array returned by field_info_fields().');
+
+    // Now rebuild the field info cache, and set a variable which will cause
+    // the cache to be cleared while it's being rebuilt; see
+    // field_test_entity_info(). Ensure the test field is still in the returned
+    // array.
+    field_info_cache_clear();
+    variable_set('field_test_clear_info_cache_in_hook_entity_info', TRUE);
+    $fields = field_info_fields();
+    $this->assertTrue(isset($fields[$field_name]), 'The test field is found in the array returned by field_info_fields() even if its cache is cleared while being rebuilt.');
+  }
 }
diff --git a/core/modules/field/tests/modules/field_test/field_test.entity.inc b/core/modules/field/tests/modules/field_test/field_test.entity.inc
index 456fe99..ae233aa 100644
--- a/core/modules/field/tests/modules/field_test/field_test.entity.inc
+++ b/core/modules/field/tests/modules/field_test/field_test.entity.inc
@@ -9,6 +9,12 @@
  * Implements hook_entity_info().
  */
 function field_test_entity_info() {
+  // If requested, clear the field cache while this hook is being called. See
+  // Drupal\field\Tests\FieldInfoTest\FieldInfoTest::testFieldInfoCache().
+  if (variable_get('field_test_clear_info_cache_in_hook_entity_info', FALSE)) {
+    field_info_cache_clear();
+  }
+
   $bundles = variable_get('field_test_bundles', array('test_bundle' => array('label' => 'Test Bundle')));
   $test_entity_modes = array(
     'full' => array(