diff -u b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php
--- b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/TestBase.php
@@ -784,6 +784,8 @@
             // directory. If this fails, a test would possibly operate in the
             // parent site. Therefore, the entire test run for this test class
             // has to be aborted.
+            // restoreEnvironment() cannot be called, because we do not know
+            // where exactly the environment setup failed.
             break;
           }
           try {
@@ -794,7 +796,7 @@
             // Abort if setUp() fails, since all test methods will fail.
             // But ensure to clean up and restore the environment, since
             // prepareEnvironment() succeeded.
-            $this->tearDown();
+            $this->restoreEnvironment();
             break;
           }
           try {
@@ -812,8 +814,10 @@
             // it is likely that all tests will fail in the same way and a
             // failure here only results in additional test artifacts that have
             // to be manually deleted.
+            $this->restoreEnvironment();
             break;
           }
+          $this->restoreEnvironment();
           // Remove the completion check record.
           TestBase::deleteAssert($completion_check_id);
         }
@@ -905,13 +909,11 @@
    *
    * Backups various current environment variables and resets them, so they do
    * not interfere with the Drupal site installation in which tests are executed
-   * and can be restored in TestBase::tearDown().
+   * and can be restored in TestBase::restoreEnvironment().
    *
    * Also sets up new resources for the testing environment, such as the public
    * filesystem and configuration directories.
    *
-   * @see TestBase::tearDown()
-   *
    * This method is private as it must only be called once by TestBase::run()
    * (multiple invocations for the same test would have unpredictable
    * consequences) and it must not be callable or overridable by test classes.
@@ -1071,7 +1073,7 @@
    * old module list.
    *
    * @see TestBase::prepareEnvironment()
-   * @see TestBase::tearDown()
+   * @see TestBase::restoreEnvironment()
    *
    * @todo Fix http://drupal.org/node/1708692 so that module enable/disable
    *   changes are immediately reflected in \Drupal::getContainer(). Until then,
@@ -1094,6 +1096,12 @@
 
   /**
    * Performs cleanup tasks after each individual test method has been run.
+   */
+  protected function tearDown() {
+  }
+
+  /**
+   * Cleans up the test environment and restores the original environment.
    *
    * Deletes created files, database tables, and reverts environment changes.
    *
@@ -1103,7 +1111,7 @@
    * @see TestBase::changeDatabasePrefix()
    * @see TestBase::prepareEnvironment()
    */
-  protected function tearDown() {
+  private function restoreEnvironment() {
     global $user, $conf;
 
     // Reset all static variables.
@@ -1412,8 +1420,9 @@
   /**
    * Ensures test files are deletable within file_unmanaged_delete_recursive().
    *
-   * Some tests chmod generated files to be read only. During tearDown() and
-   * other cleanup operations, these files need to get deleted too.
+   * Some tests chmod generated files to be read only. During
+   * TestBase::restoreEnvironment() and other cleanup operations, these files
+   * need to get deleted too.
    */
   public static function filePreDeleteCallback($path) {
     chmod($path, 0700);
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Utility/Error.php
+++ b/core/lib/Drupal/Core/Utility/Error.php
@@ -89,9 +89,12 @@ public static function decodeException(\Exception $exception) {
    */
   public static function renderExceptionSafe(\Exception $exception) {
     $decode = static::decodeException($exception);
+    $backtrace = $decode['backtrace'];
     unset($decode['backtrace']);
 
-    return String::format('%type: !message in %function (line %line of %file).', $decode);
+    $output = String::format('%type: !message in %function (line %line of %file).', $decode);
+    $output .= '<pre>' . static::formatBacktrace($backtrace) . '</pre>';
+    return $output;
   }
 
   /**
only in patch2:
unchanged:
--- a/core/modules/simpletest/lib/Drupal/simpletest/Tests/BrokenSetUpTest.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/Tests/BrokenSetUpTest.php
@@ -46,41 +46,74 @@ function setUp() {
     }
     // If the test is being run from within simpletest, set up the broken test.
     else {
-      $this->pass(t('The test setUp() method has been run.'));
-      // Don't call parent::setUp(). This should trigger an error message.
+      if (file_get_contents($this->originalFileDirectory . '/simpletest/trigger') === 'setup') {
+        throw new \Exception('Broken setup');
+      }
+      $this->pass('The setUp() method has run.');
     }
   }
 
   function tearDown() {
     // If the test is being run from the main site, tear down normally.
     if (!drupal_valid_test_ua()) {
+      unlink($this->originalFileDirectory . '/simpletest/trigger');
       parent::tearDown();
     }
+    // If the test is being run from within simpletest, output a message.
     else {
-      // If the test is being run from within simpletest, output a message.
-      $this->pass(t('The tearDown() method has run.'));
+      if (file_get_contents($this->originalFileDirectory . '/simpletest/trigger') === 'teardown') {
+        throw new \Exception('Broken teardown');
+      }
+      $this->pass('The tearDown() method has run.');
     }
   }
 
   /**
    * Runs this test case from within the simpletest child site.
    */
-  function testBreakSetUp() {
+  function testMethod() {
     // If the test is being run from the main site, run it again from the web
     // interface within the simpletest child site.
     if (!drupal_valid_test_ua()) {
+      // Verify that a broken setUp() method is caught.
+      file_put_contents($this->originalFileDirectory . '/simpletest/trigger', 'setup');
+      $edit['Drupal\simpletest\Tests\BrokenSetUpTest'] = TRUE;
+      $this->drupalPostForm('admin/config/development/testing', $edit, t('Run tests'));
+      $this->assertRaw('Broken setup');
+      $this->assertNoRaw('The setUp() method has run.');
+      $this->assertNoRaw('Broken test');
+      $this->assertNoRaw('The test method has run.');
+      $this->assertNoRaw('Broken teardown');
+      $this->assertNoRaw('The tearDown() method has run.');
+
+      // Verify that a broken tearDown() method is caught.
+      file_put_contents($this->originalFileDirectory . '/simpletest/trigger', 'teardown');
       $edit['Drupal\simpletest\Tests\BrokenSetUpTest'] = TRUE;
       $this->drupalPostForm('admin/config/development/testing', $edit, t('Run tests'));
+      $this->assertNoRaw('Broken setup');
+      $this->assertRaw('The setUp() method has run.');
+      $this->assertNoRaw('Broken test');
+      $this->assertRaw('The test method has run.');
+      $this->assertRaw('Broken teardown');
+      $this->assertNoRaw('The tearDown() method has run.');
 
-      // Verify that the broken test and its tearDown() method are skipped.
-      $this->assertRaw(t('The test setUp() method has been run.'));
-      $this->assertRaw(t('The test cannot be executed because it has not been set up properly.'));
-      $this->assertNoRaw(t('The test method has run.'));
-      $this->assertNoRaw(t('The tearDown() method has run.'));
+      // Verify that a broken test method is caught.
+      file_put_contents($this->originalFileDirectory . '/simpletest/trigger', 'test');
+      $edit['Drupal\simpletest\Tests\BrokenSetUpTest'] = TRUE;
+      $this->drupalPostForm('admin/config/development/testing', $edit, t('Run tests'));
+      $this->assertNoRaw('Broken setup');
+      $this->assertRaw('The setUp() method has run.');
+      $this->assertRaw('Broken test');
+      $this->assertNoRaw('The test method has run.');
+      $this->assertNoRaw('Broken teardown');
+      $this->assertRaw('The tearDown() method has run.');
     }
     // If the test is being run from within simpletest, output a message.
     else {
-      $this->pass(t('The test method has run.'));
+      if (file_get_contents($this->originalFileDirectory . '/simpletest/trigger') === 'test') {
+        throw new \Exception('Broken test');
+      }
+      $this->pass('The test method has run.');
     }
   }
 }