diff --git a/tools/selftest.js b/tools/selftest.js
index beb5197de8..90c99ed4f4 100644
--- a/tools/selftest.js
+++ b/tools/selftest.js
@@ -464,6 +464,15 @@ _.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?
+  read: function (filename) {
+    var self = this;
+    return fs.readFileSync(path.join(self.cwd, filename), 'utf8');
+  },
+
   // Delete a file in the sandbox. 'filename' is as in write().
   unlink: function (filename) {
     var self = this;
diff --git a/tools/tests/run.js b/tools/tests/run.js
index 390771689e..3be53f0edb 100644
--- a/tools/tests/run.js
+++ b/tools/tests/run.js
@@ -53,12 +53,13 @@ selftest.define("run --once", function () {
   run.waitSecs(5);
   run.match("once test\n");
   s.write('empty.js', 'null');
+  var originalRelease = s.read('.meteor/release');
   s.write('.meteor/release', 'v1');
   utils.sleepMs(2000); // sorry, hard to avoid
   run.stop();
   run.forbidAll("updated");
   s.unlink('empty.js');
-  s.write('.meteor/release', 'none');
+  s.write('.meteor/release', originalRelease);
 
   // running a different program
   run = s.run("--once", "--program", "other");