diff --git a/tests/generators/run_generators_in_browser.js b/tests/generators/run_generators_in_browser.js
index 97dcf9727..280a59fe5 100644
--- a/tests/generators/run_generators_in_browser.js
+++ b/tests/generators/run_generators_in_browser.js
@@ -24,7 +24,7 @@ async function runLangGeneratorInBrowser(browser, filename, codegenFn) {
   await browser.execute(codegenFn);
   var elem = await browser.$("#importExport");
   var result = await elem.getValue();
-  fs.writeFile(filename, result, function(err) {
+  fs.writeFileSync(filename, result, function(err) {
     if (err) {
       return console.log(err);
     }