diff --git a/core/includes/install.inc b/core/includes/install.inc
index 7d51db6..1f52907 100644
--- a/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -980,20 +980,26 @@ function drupal_check_module($module) {
     foreach ($requirements as $requirement) {
       if (isset($requirement['severity']) && $requirement['severity'] == REQUIREMENT_ERROR) {
         $message = [];
+        // If the requirement description is already a render array, add it to
+        // the message array.
         if (is_array($requirement['description'])) {
           $message['description'] = $requirement['description'];
         }
+        // Otherwise, add a #markup element for the description string.
         else {
           $message['description'] = [
             '#markup' => $requirement['description'],
-            '#suffix' => ' ',
+            '#weight' => 0,
           ];
         }
+        // If a required value was provided for the item, add it to the error
+        // message. See the hook_requirements() documentation.
         if (isset($requirement['value']) && $requirement['value']) {
           $message['version'] = [
-            '#prefix' => '(',
+            '#prefix' => ' (',
             '#markup' => t('Currently using @item version @version', array('@item' => $requirement['title'], '@version' => $requirement['value'])),
             '#suffix' => ')',
+            '#weight' => 1,
           ];
         }
         \Drupal::service('renderer')->renderPlain($message);
diff --git a/core/modules/system/src/Tests/Module/DependencyTest.php b/core/modules/system/src/Tests/Module/DependencyTest.php
index 9fed238..05f17cd 100644
--- a/core/modules/system/src/Tests/Module/DependencyTest.php
+++ b/core/modules/system/src/Tests/Module/DependencyTest.php
@@ -108,7 +108,7 @@ function testEnableRequirementsFailureDependency() {
     \Drupal::state()->set('requirements1_test.phase', 'install');
     \Drupal::state()->set('requirements1_test.severity', REQUIREMENT_ERROR);
 
-      // Attempt to install both modules at the same time.
+    // Attempt to install both modules at the same time.
     $edit = array();
     $edit['modules[Testing][requirements1_test][enable]'] = 'requirements1_test';
     $edit['modules[Testing][requirements2_test][enable]'] = 'requirements2_test';
diff --git a/core/modules/system/src/Tests/Module/HookRequirementsTest.php b/core/modules/system/src/Tests/Module/HookRequirementsTest.php
index 016c59e..4369f10 100644
--- a/core/modules/system/src/Tests/Module/HookRequirementsTest.php
+++ b/core/modules/system/src/Tests/Module/HookRequirementsTest.php
@@ -48,9 +48,8 @@ class HookRequirementsTest extends ModuleTestBase {
    * @see requirements1_test_requirements()
    */
   function testHookRequirements() {
-
-    // Test installing the module with all possible combinations of values
-    // in the hook_requirements() hook.
+    // Test installing the module with all possible combinations of values in
+    // the hook_requirements() hook.
 
     // Test all allowed severities.
     foreach ([REQUIREMENT_ERROR, REQUIREMENT_WARNING, REQUIREMENT_OK, REQUIREMENT_INFO] as $this->severity) {
@@ -71,8 +70,8 @@ function testHookRequirements() {
     \Drupal::state()->set('requirements1_test.severity', REQUIREMENT_INFO);
     $this->container->get('module_installer')->install(['requirements1_test']);
 
-    // Test the status report with all possible combinations of values
-    // in the hook_requirements() hook.
+    // Test the status report with all possible combinations of values in the
+    // hook_requirements() hook.
     // Test all allowed severities.
     foreach ([REQUIREMENT_ERROR, REQUIREMENT_WARNING, REQUIREMENT_OK, REQUIREMENT_INFO] as $this->severity) {
       // Test all allowed phases.
@@ -87,8 +86,6 @@ function testHookRequirements() {
         }
       }
     }
-
-    // @todo Test update phase separately.
   }
 
   /**
@@ -97,7 +94,6 @@ function testHookRequirements() {
    * @see requirements1_test_requirements()
    */
   protected function doInstallTest() {
-
     // Only install phase requirement errors should fail installation.
     if (($this->phase == 'install') && ($this->severity == REQUIREMENT_ERROR)) {
       $success = FALSE;
@@ -138,7 +134,6 @@ protected function doInstallTest() {
     else {
       $this->assertExpectedRequirementsMessages();
     }
-
   }
 
   /**
@@ -147,7 +142,6 @@ protected function doInstallTest() {
    * @see requirements1_test_requirements()
    */
   protected function doRuntimeTest() {
-
     // Configure the module's hook_requirements().
     \Drupal::state()->set('requirements1_test.phase', $this->phase);
     \Drupal::state()->set('requirements1_test.severity', $this->severity);
@@ -176,30 +170,30 @@ protected function doRuntimeTest() {
   protected function assertExpectedRequirementsMessages() {
     // @todo Currently, the 'title' is only displayed during the install phase
     //   if the 'value' is also defined. This may not be intentional. Fix in
-    //   https://www.drupal.org/node/FILE-ME.
+    //   https://www.drupal.org/node/2549803.
     if (($this->phase == 'install') && !$this->useValue) {
       $this->assertNoText('Requirements 1 title');
     }
     else {
       // Normally, the requirement title should always be displayed.
-      $this->assertText('Requirements 1 title');
+      $this->assertRaw('Requirements 1 title with <em>markup!</em>');
     }
 
     // If the requirements description was a render array, check that it was
     // rendered correctly.
     if ($this->descriptionArray) {
-      $this->assertText('Requirements 1 render array');
+      $this->assertRaw('Requirements 1 render array with <em>markup!</em>');
       $this->assertText('Requirements 1 first item');
       $this->assertText('Requirements 1 second item');
     }
     // Otherwise, test for the string message.
     else {
-      $this->assertText('Requirements 1 string');
+      $this->assertRaw('Requirements 1 string with <em>markup!</em>');
     }
 
     // The value should be displayed if it was set.
     if ($this->useValue) {
-      $this->assertText('Requirements 1 value text');
+      $this->assertRaw('Requirements 1 value text with <em>markup!</em>');
     }
     else {
       $this->assertNoText('Requirements 1 value text');
diff --git a/core/modules/system/tests/modules/requirements1_test/requirements1_test.install b/core/modules/system/tests/modules/requirements1_test/requirements1_test.install
index c02dc80..943dcb0 100644
--- a/core/modules/system/tests/modules/requirements1_test/requirements1_test.install
+++ b/core/modules/system/tests/modules/requirements1_test/requirements1_test.install
@@ -4,7 +4,8 @@
  * Implements hook_requirements().
  *
  * Test modules may use four state variables to control this hook:
- * - requirements1_test.phase: Whether to add the message for 'install', 'update', or 'runtime' phase.
+ * - requirements1_test.phase: Whether to add the message for 'install',
+ *   'update', or 'runtime' phase.
  * - requirements1_test.severity: The value for the 'severity' of the
  *   requirement, e.g. REQUIREMENT_ERROR
  * - requirements1_test.description_array: Boolean indicating whether to use a
@@ -25,14 +26,14 @@ function requirements1_test_requirements($phase) {
 
   // Prepare the requirement message.
   $requirement = [];
-  $requirement['title'] = 'Requirements 1 title';
+  $requirement['title'] = t('Requirements 1 title with <em>markup!</em>');
 
   // Use the severity level set in the test.
   $requirement['severity'] = \Drupal::state()->get('requirements1_test.severity');
 
   // Add a value to the requirement if indicated in the test.
   if (\Drupal::state()->get('requirements1_test.use_value')) {
-    $requirement['value'] = 'Requirements 1 value text';
+    $requirement['value'] = t('Requirements 1 value text with <em>markup!</em>');
   }
 
   // Use a render array or a string for the description based on the value set
@@ -40,15 +41,14 @@ function requirements1_test_requirements($phase) {
   if (\Drupal::state()->get('requirements1_test.description_array')) {
     $requirement['description'] = [
       '#theme' => 'item_list',
-      '#title' => 'Requirements 1 render array',
+      '#title' => t('Requirements 1 render array with <em>markup!</em>'),
       '#items' => ['Requirements 1 first item', 'Requirements 1 second item'],
     ];
   }
   else {
-    $requirement['description'] = 'Requirements 1 string.';
+    $requirement['description'] = t('Requirements 1 string with <em>markup!</em>.');
   }
 
   $requirements['requirements1_test'] = $requirement;
   return $requirements;
-
 }