--- a/devtools/client/webconsole/test/browser_webconsole_bug_613642_prune_scroll.js
+++ b/devtools/client/webconsole/test/browser_webconsole_bug_613642_prune_scroll.js
@@ -17,19 +17,21 @@ add_task(function* () {
 
   hud.jsterm.clearOutput();
 
   let outputNode = hud.outputNode;
 
   Services.prefs.setIntPref("devtools.hud.loglimit.console", 140);
   let scrollBoxElement = hud.ui.outputWrapper;
 
-  for (let i = 0; i < 150; i++) {
-    content.console.log("test message " + i);
-  }
+  ContentTask.spawn(gBrowser.selectedBrowser, {}, function* () {
+    for (let i = 0; i < 150; i++) {
+      content.console.log("test message " + i);
+    }
+  });
 
   yield waitForMessages({
     webconsole: hud,
     messages: [{
       text: "test message 149",
       category: CATEGORY_WEBDEV,
       severity: SEVERITY_LOG,
     }],