diff --git a/modules/simpletest/tests/file.test b/modules/simpletest/tests/file.test
index 3df31ba5fe0b448db5a0c2640b4ab69f6b86177e..ebaa0c03483fa3ff27568b2a9027f70c00b8f0fd 100644
--- a/modules/simpletest/tests/file.test
+++ b/modules/simpletest/tests/file.test
@@ -2578,6 +2578,15 @@ class FileNameMungingTest extends FileTestCase {
     $this->assertNotEqual($munged_name, $this->name, t('The new filename (%munged) has been modified from the original (%original)', array('%munged' => $munged_name, '%original' => $this->name)));
   }
 
+  /**
+   * Tests munging with a null byte in the filename.
+   */
+  function testMungeNullByte() {
+    $prefix = $this->randomName();
+    $filename = $prefix . '.' . $this->bad_extension . "\0.txt";
+    $this->assertEqual(file_munge_filename($filename, ''), $prefix . '.' . $this->bad_extension . '_.txt', 'A filename with a null byte is correctly munged to remove the null byte.');
+  }
+
   /**
    * If the allow_insecure_uploads variable evaluates to true, the file should
    * come out untouched, no matter how evil the filename.