diff --git a/modules/system/system.test b/modules/system/system.test
index abd21aa..84ed269 100644
--- a/modules/system/system.test
+++ b/modules/system/system.test
@@ -2681,3 +2681,34 @@ class SystemIndexPhpTest extends DrupalWebTestCase {
   }
 }
 
+/**
+ * Test token replacement in strings.
+ */
+class TokenScanTest extends DrupalWebTestCase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Token scanning',
+      'description' => 'Scan token-like patterns in a dummy text to check token scanning.',
+      'group' => 'System',
+    );
+  }
+
+  /**
+   * Scans dummy text, then tests the output.
+   */
+  function testTokenScan() {
+    // Define text with valid and not valid, fake and existing token-like
+    // strings.
+    $text = 'First a [valid:simple], but dummy token, and a dummy [valid:token with: spaces].';
+    $text .= 'Then a [not valid:token].';
+    $text .= 'Last an existing token: [node:author:name].';
+    $token_wannabes = token_scan($text);
+
+    $this->assertTrue(isset($token_wannabes['valid']['simple']), 'A simple valid token has been matched.');
+    $this->assertTrue(isset($token_wannabes['valid']['token with: spaces']), 'A valid token with space characters in the token name has been matched.');
+    $this->assertFalse(isset($token_wannabes['not valid']), 'An invalid token with spaces in the token type has not been matched.');
+    $this->assertTrue(isset($token_wannabes['node']), 'An existing valid token has been matched.');
+  }
+}
+