Close popup automatically after a successful save

tests/helpers.js

@@ -74,6 +74,11 @@ function loadPopupScript({ initialSettings } = {}) {
   );
   const savedCalls = [];
 
+  window.__closeCalled = false;
+  window.close = () => {
+    window.__closeCalled = true;
+  };
+
   window.chrome = {
     storage: {
       sync: {