Another attempt to make "run --once" test more reliable.

tools/tests/apps/once/once.js

@@ -14,8 +14,23 @@ if (process.env.RUN_ONCE_OUTCOME === "hang") {
 
 if (process.env.RUN_ONCE_OUTCOME === "mongo") {
   var test = new Mongo.Collection('test');
-  Meteor.startup(function () {
-    test.insert({ value: 86 });
+  var triesLeft = 10;
+
+  function tryInsert() {
+    try {
+      test.insert({ value: 86 });
+    } catch (e) {
+      if (--triesLeft <= 0) {
+        throw e;
+      }
+
+      console.log("insert failed; retrying:", String(e.stack || e));
+      setTimeout(tryInsert, 1000);
+      return;
+    }
+
     process.exit(test.findOne().value);
-  });
+  }
+
+  Meteor.startup(tryInsert);
 }