--- a/testing/talos/talos/tests/devtools/addon/content/tests/debugger/debugger-helpers.js
+++ b/testing/talos/talos/tests/devtools/addon/content/tests/debugger/debugger-helpers.js
@@ -167,22 +167,24 @@ exports.createContext = createContext;
 function selectSource(dbg, url) {
   dump(`Selecting source: ${url}\n`);
   const line = 1;
   const source = findSource(dbg, url);
   dbg.actions.selectLocation({ sourceId: source.get("id"), line });
   return waitForState(
     dbg,
     state => {
+      dump(`Checking if source is loaded\n`);
       const source = dbg.selectors.getSelectedSource(state);
       const isLoaded = source && source.get("loadedState") === "loaded";
       if (!isLoaded) {
         return false;
       }
 
+      dump(`Waiting for symbols\n`);
       // wait for symbols -- a flat map of all named variables in a file -- to be calculated.
       // this is a slow process and becomes slower the larger the file is
       return dbg.selectors.hasSymbols(state, source.toJS());
     },
     "selected source"
   );
 }