diff --git a/hphp/test/quick/builtin_extension_StringBuffer.php b/hphp/test/quick/builtin_extension_StringBuffer.php
deleted file mode 100644
index 60e4f42b9..000000000
--- a/hphp/test/quick/builtin_extension_StringBuffer.php
+++ /dev/null
@@ -1,32 +0,0 @@
-<?php
-
-include __DIR__."/builtin_extensions.inc";
-
-class A_StringBuffer extends StringBuffer {
-  public $___x;
-}
-test("StringBuffer");
-
-function main() {
-  echo "================\n";
-
-  $x = new StringBuffer();
-  $x->foo = 123;
-  var_dump($x);
-  var_dump($x->foo);
-
-  echo "================\n";
-
-  class Foo extends StringBuffer {
-    public $foo = 42;
-    public $bar = 'seven';
-  }
-  $y = new Foo;
-  $y->biz = array();
-  var_dump($y);
-  var_dump($y->foo);
-  var_dump($y->bar);
-  var_dump($y->biz);
-}
-
-main();
diff --git a/hphp/test/quick/builtin_extension_StringBuffer.php.expectf b/hphp/test/quick/builtin_extension_StringBuffer.php.expectf
deleted file mode 100644
index 174b5c515..000000000
--- a/hphp/test/quick/builtin_extension_StringBuffer.php.expectf
+++ /dev/null
@@ -1,53 +0,0 @@
-StringBuffer
-object(StringBuffer)#1 (0) {
-}
-string(24) "O:12:"StringBuffer":0:{}"
-object(StringBuffer)#2 (0) {
-}
-array(3) {
-  [0]=>
-  string(11) "__construct"
-  [1]=>
-  string(6) "append"
-  [2]=>
-  string(6) "detach"
-}
-================
-A_StringBuffer
-object(A_StringBuffer)#3 (1) {
-  ["___x"]=>
-  NULL
-}
-string(39) "O:14:"A_StringBuffer":1:{s:4:"___x";N;}"
-object(A_StringBuffer)#4 (1) {
-  ["___x"]=>
-  NULL
-}
-array(3) {
-  [0]=>
-  string(11) "__construct"
-  [1]=>
-  string(6) "append"
-  [2]=>
-  string(6) "detach"
-}
-================
-object(StringBuffer)#3 (1) {
-  ["foo"]=>
-  int(123)
-}
-int(123)
-================
-object(Foo)#4 (3) {
-  ["foo"]=>
-  int(42)
-  ["bar"]=>
-  string(5) "seven"
-  ["biz"]=>
-  array(0) {
-  }
-}
-int(42)
-string(5) "seven"
-array(0) {
-}