diff --git a/core/lib/Drupal/Core/StreamWrapper/SystemStream.php b/core/lib/Drupal/Core/StreamWrapper/SystemStream.php
index 07e365b..57e3d60 100644
--- a/core/lib/Drupal/Core/StreamWrapper/SystemStream.php
+++ b/core/lib/Drupal/Core/StreamWrapper/SystemStream.php
@@ -34,7 +34,7 @@ public function getOwnerName($uri = NULL) {
     $uri_parts = explode('://', $uri, 2);
     if (count($uri_parts) === 1) {
       // The delimiter ('://') was not found in $uri, malformed $uri passed.
-      throw new \InvalidArgumentException('Malformed $uri parameter passed: %s', $uri);
+      throw new \InvalidArgumentException(sprintf('Malformed uri parameter passed: %s', $uri));
     }
     else {
       list($scheme, $target) = $uri_parts;
diff --git a/core/modules/system/src/Tests/File/SystemStreamUnitTest.php b/core/modules/system/src/Tests/File/SystemStreamUnitTest.php
index bb27b4c..691f309 100644
--- a/core/modules/system/src/Tests/File/SystemStreamUnitTest.php
+++ b/core/modules/system/src/Tests/File/SystemStreamUnitTest.php
@@ -41,16 +41,11 @@ public static function getInfo() {
   public function setUp() {
     parent::setUp();
     drupal_static_reset('file_get_stream_wrappers');
+
     // Add default profile for the purposes of this test
     new Settings(Settings::getAll() + array(
       'install_profile' => 'standard'
     ));
-
-    // Drupal::container() doesn't contain theme state info which is already
-    // saved in KernelTestBase::container. Need to transfer this across.
-    \Drupal::state()->set('system.theme.data', $this->container->get('state')->get('system.theme.data'));
-    \Drupal::state()->set('system.theme.files', $this->container->get('state')->get('system.theme.files'));
-    \Drupal::service('theme_handler')->enable(array('stark', 'bartik', 'seven'));
   }
 
   /**
@@ -61,6 +56,37 @@ public function tearDown() {
   }
 
   /**
+   * Test Invalid stream uri.
+   */
+  public function testInvalidStreamUriException() {
+    $bad_uris = array(
+      'invalid/uri',
+      'invalid_uri',
+      'module/invalid/uri',
+      'module/invalid_uri',
+      'module:invalid_uri',
+      'module::/invalid/uri',
+      'module::/invalid_uri',
+      'module//:invalid/uri',
+      'module//invalid_uri',
+      'module//invalid/uri',
+    );
+
+    /** @var \Drupal\Core\StreamWrapper\ModuleStream $instance */
+    $instance = file_stream_wrapper_get_instance_by_scheme('module');
+
+    foreach ($bad_uris as $bad_uri) {
+      try {
+        $instance->getOwnerName($bad_uri);
+        $this->fail(format_string('Invalid uri %uri not detected.', array('%uri' => $bad_uri)));
+      }
+      catch (\InvalidArgumentException $e) {
+        $this->pass(format_string('Throw exception on invalid uri %uri supplied.', array('%uri' => $bad_uri)));
+      }
+    }
+  }
+
+  /**
    * Test the Module stream wrapper functions.
    */
   public function testModuleStream() {
@@ -161,21 +187,24 @@ public function testProfileStream() {
    * Test the Theme stream wrapper functions.
    */
   public function testThemeStream() {
-    // Disable Bartik theme.
-    $system_theme_disabled = \Drupal::config('system.theme.disabled');
-    $this->assertNotIdentical($system_theme_disabled->get('bartik'), 0, format_string('%bartik theme was enabled.', array('%bartik' => 'Bartik')));
-    $system_theme_disabled->set('bartik', 0)->save();
-    $this->assertIdentical($system_theme_disabled->get('bartik'), 0, format_string('Now disable %bartik theme.', array('%bartik' => 'Bartik')));
+    /** @var \Drupal\Core\Extension\ThemeHandler $theme_handler */
+    $theme_handler = \Drupal::service('theme_handler');
+
+    // Enable Stark, Bartik and Seven themes.
+    $theme_handler->enable(array('bartik', 'seven', 'stark'));
 
     // Set admin theme to Seven.
     $system_theme = \Drupal::config('system.theme');
     $this->assertNull($system_theme->get('admin'), 'No admin theme was set.');
     $system_theme->set('admin', 'seven')->save();
-    $this->assertEqual($system_theme->get('admin'), 'seven', format_string('Now make %seven the admin theme.', array('%seven' => 'Seven')));
+    $this->assertEqual($system_theme->get('admin'), 'seven', format_string('Make %seven the admin theme.', array('%seven' => 'Seven')));
 
     // Set default theme to Bartik.
-    $system_theme->set('default', 'bartik')->save();
-    $this->assertEqual($system_theme->get('default'), 'bartik', format_string('Now make %bartik the default theme.', array('%bartik' => 'Bartik')));
+    $theme_handler->setDefault('bartik');
+    $this->assertEqual($theme_handler->getDefault(), 'bartik', format_string('Make %bartik the default theme.', array('%bartik' => 'Bartik')));
+
+    // Disable Stark theme.
+    $theme_handler->disable(array('stark'));
 
     $uri1 = 'theme://seven';
     $uri2 = 'theme://seven/style.css';
@@ -187,6 +216,7 @@ public function testThemeStream() {
     $uri8 = 'theme://default/bartik.info.yml';
     $uri9 = 'theme://admin';
     $uri10 = 'theme://admin/fake.info.yml';
+    $uri11 = 'theme://stark/stark.info.yml';
 
     /** @var \Drupal\Core\StreamWrapper\ThemeStream $instance */
     $instance = file_stream_wrapper_get_instance_by_scheme('theme');
@@ -202,6 +232,7 @@ public function testThemeStream() {
     $this->assertEqual($instance->getOwnerName($uri8), 'bartik', format_string('Lookup real name of %default for a resource.', array('%default' => 'theme://default')));
     $this->assertEqual($instance->getOwnerName($uri9), 'seven', format_string('Lookup real name of %admin for a partial URI.', array('%admin' => 'theme://admin')));
     $this->assertEqual($instance->getOwnerName($uri10), 'seven', format_string('Lookup real name of %admin even for a non-existing resource.', array('%admin' => 'theme://admin')));
+    $this->assertFalse($instance->getOwnerName($uri11), "Fail returning a disabled theme's name.");
 
     // getTarget()
     $this->assertEqual($instance->getTarget($uri1), '', 'Return empty target for a partial URI giving only the theme.');
@@ -214,6 +245,7 @@ public function testThemeStream() {
     $this->assertEqual($instance->getTarget($uri8), 'bartik.info.yml', format_string("Extract target from a resource located in a subdirectory of %default.", array('%default' => 'theme://default')) . $instance->getTarget($uri8));
     $this->assertEqual($instance->getTarget($uri9), '', format_string('Return empty target for a partial URI giving only %admin.', array('%admin' => 'theme://admin')));
     $this->assertFalse($instance->getTarget($uri10), format_string("Fail returning target for a non-existing resource within %admin.", array('%admin' => 'theme://admin')));
+    $this->assertFalse($instance->getTarget($uri11), "Fail returning a target for a disabled theme.");
 
     // getDirectoryPath()
     $this->assertEqual($instance->getDirectoryPath($uri1), 'core/themes/seven', "Lookup theme's directory path for a partial URI.");
@@ -226,6 +258,7 @@ public function testThemeStream() {
     $this->assertEqual($instance->getDirectoryPath($uri8), 'core/themes/bartik', format_string('Lookup real directory path of %default for a resource.', array('%default' => 'theme://default')));
     $this->assertEqual($instance->getDirectoryPath($uri9), 'core/themes/seven', format_string('Lookup real directory path of %admin for a partial URI.', array('%admin' => 'theme://admin')));
     $this->assertEqual($instance->getDirectoryPath($uri10), 'core/themes/seven', format_string('Lookup real directory path of %admin for a resource.', array('%admin' => 'theme://admin')));
+    $this->assertFalse($instance->getDirectoryPath($uri11), "Fail returning a disabled theme's directory path.");
 
     // getExternalUrl()
     $base_url = \Drupal::request()->getUri();
@@ -239,6 +272,7 @@ public function testThemeStream() {
     $this->assertEqual($instance->getExternalUrl($uri8), $base_url . 'core/themes/bartik/bartik.info.yml', format_string('Lookup external url of %default for a resource.', array('%default' => 'theme://default')));
     $this->assertEqual($instance->getExternalUrl($uri9), $base_url . 'core/themes/seven', format_string('Lookup external url of %admin for a partial URI.', array('%admin' => 'theme://admin')));
     $this->assertEqual($instance->getExternalUrl($uri10), $base_url . 'core/themes/seven/fake.info.yml', format_string('Lookup external url of %admin for a resource.', array('%admin' => 'theme://admin')));
+    $this->assertFalse($instance->getExternalUrl($uri11), "Fail returning a disabled theme's external url.");
 
   }
 }