diff --git a/dom/filesystem/tests/script_fileList.js b/dom/filesystem/tests/script_fileList.js
index b21ba3550506..85d279ad70e8 100644
--- a/dom/filesystem/tests/script_fileList.js
+++ b/dom/filesystem/tests/script_fileList.js
@@ -8,6 +8,46 @@ function createProfDFile() {
            .get('ProfD', Ci.nsIFile);
 }
 
+// Creates a parametric arity directory hierarchy as a function of depth.
+// Each directory contains one leaf file, and subdirectories of depth [1, depth).
+// e.g. for depth 3:
+//
+// subdir3
+// - file.txt
+// - subdir2
+//   - file.txt
+//   - subdir1
+//     - file.txt
+// - subdir1
+//   - file.txt
+//
+// Returns the parent directory of the subtree.
+function createTreeFile(depth, parent) {
+  if (!parent) {
+    parent = Cc["@mozilla.org/file/directory_service;1"]
+                .getService(Ci.nsIDirectoryService)
+                .QueryInterface(Ci.nsIProperties)
+                .get('TmpD', Ci.nsIFile);
+    parent.append('dir-tree-test');
+    parent.createUnique(Components.interfaces.nsIFile.DIRECTORY_TYPE, 0o700);
+  }
+
+  var nextFile = parent.clone();
+  if (depth == 0) {
+    nextFile.append('file.txt');
+    nextFile.create(Components.interfaces.nsIFile.NORMAL_FILE_TYPE, 0o600);
+  } else {
+    nextFile.append('subdir' + depth);
+    nextFile.createUnique(Components.interfaces.nsIFile.DIRECTORY_TYPE, 0o700);
+    // Decrement the maximal depth by one for each level of nesting.
+    for (i = 0; i < depth; i++) {
+      createTreeFile(i, nextFile);
+    }
+  }
+
+  return parent;
+}
+
 function createRootFile() {
   var testFile = createProfDFile();
 
@@ -52,6 +92,8 @@ addMessageListener("dir.open", function (e) {
 
   switch (e.path) {
     case 'ProfD':
+      // Note that files in the profile directory are not guaranteed to persist-
+      // see bug 1284742.
       testFile = createProfDFile();
       break;
 
@@ -62,6 +104,10 @@ addMessageListener("dir.open", function (e) {
     case 'test':
       testFile = createTestFile();
       break;
+
+    case 'tree':
+      testFile = createTreeFile(3);
+      break;
   }
 
   sendAsyncMessage("dir.opened", {
diff --git a/dom/filesystem/tests/test_basic.html b/dom/filesystem/tests/test_basic.html
index 0b0fa97ebc6d..d2e40aa720c3 100644
--- a/dom/filesystem/tests/test_basic.html
+++ b/dom/filesystem/tests/test_basic.html
@@ -129,7 +129,7 @@ function test_inputGetFiles() {
 var tests = [
   function() { setup_tests(next); },
 
-  function() { create_fileList('ProfD') },
+  function() { create_fileList('tree') },
   function() { test_basic(directory, next); },
   function() { test_getFilesAndDirectories(directory, true, next); },
   function() { test_getFiles(directory, false, next); },