From 5358af451cf073e538aad35bf752e2845010be20 Mon Sep 17 00:00:00 2001
From: Avital Oliver <avital@thewe.net>
Date: Thu, 8 May 2014 16:21:05 -0700
Subject: [PATCH] selftest: return null when reading a file that doesn't exist

---
 tools/selftest.js | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/tools/selftest.js b/tools/selftest.js
index 494fe53ea2..0d84ac73e8 100644
--- a/tools/selftest.js
+++ b/tools/selftest.js
@@ -464,13 +464,16 @@ _.extend(Sandbox.prototype, {
     fs.writeFileSync(path.join(self.cwd, filename), contents, 'utf8');
   },
 
-  // Reads a file in the sandbox as a utf8 string. 'filename' is a path
-  // intepreted relative to the Sandbox's cwd.  throws if the file does not
-  // exist.
-  // XXX maybe it should return null if the file does not exist?
+  // Reads a file in the sandbox as a utf8 string. 'filename' is a
+  // path intepreted relative to the Sandbox's cwd.  Returns null if
+  // file does not exist.
   read: function (filename) {
     var self = this;
-    return fs.readFileSync(path.join(self.cwd, filename), 'utf8');
+    var file = path.join(self.cwd, filename);
+    if (!fs.existsSync(file))
+      return null;
+    else
+      return fs.readFileSync(path.join(self.cwd, filename), 'utf8');
   },
 
   // Delete a file in the sandbox. 'filename' is as in write().