MDL-56210 behat: Ensure behat waits for dependancy manager

lib/form/form.js

@@ -23,6 +23,9 @@ if (typeof M.form.dependencyManager === 'undefined') {
             this._hides = {};
             this._dirty = {};
 
+            // Let behat know that JS is pending.
+            M.util.js_pending('mform-dependency-manager-' + this.get('form').get('id'));
+
             // Setup event handlers.
             Y.Object.each(this.get('dependencies'), function(value, i) {
                 var elements = this.elementsByName(i);
@@ -56,6 +59,9 @@ if (typeof M.form.dependencyManager === 'undefined') {
             }, this);
 
             this.updateAllDependencies();
+
+            // Let behat know that JS is complete.
+            M.util.js_complete('mform-dependency-manager-' + this.get('form').get('id'));
         },
 
         /**
@@ -587,6 +593,12 @@ M.form.initFormDependencies = function(Y, formid, dependencies) {
  */
 M.form.updateFormState = function(formid) {
     if (formid in M.form.dependencyManagers) {
+        // Let behat know that JS is pending.
+        M.util.js_pending('mform-dependency-manager-' + formid);
+
         M.form.dependencyManagers[formid].updateAllDependencies();
+
+        // Let behat know that JS is complete.
+        M.util.js_complete('mform-dependency-manager-' + formid);
     }
 };