Possible fix for the error asserting issue

[ocrest]

Hi,

This pull-request is just an idea (maybe crazy) which perhaps solve the issue emberjs/ember.js#15013

The bottom line is this: we can set a global window.onerror handler before the component render, and save all uncaught errors (test-module-for-component.js#L243-L247).

Then, after the component was rendered, we rethrow these errors to be caught by the test framework error assertion: test-module-for-component.js#L258-L263

I created a simple test with this component:

// A component which throws an error during render:
var BadComponent = Ember.Component.extend({
  layout: Ember.Handlebars.compile('<input type="text" onfocus={{action "focus"}}>'),
  didInsertElement() {
    this.set('input', this.element.querySelector('input'));
  },
  didRender() {
    this.get('input').focus();
  },
  actions: {
    focus() {
      this.get('unexistedMethod')();
    }
  }
});

— it sets the focus to the child <input> element in the didRender hook, and this triggers the focus() closure action, which, in turn, throws an error (because there is a call on the undefined property).

With this hacky fix the throws assertion

test('it correctly handles uncaught errors when rendering a component', function() {
  var self = this;
  throws(function() {
    self.render('{{bad-component}}');
  });
});

now successfully catches this error.

Any thoughts?

[rwjblue]

The underlying issue reported in emberjs/ember.js#15013 was fixed by emberjs/ember.js#15871, which essentially reverts emberjs/ember.js#14898 and adds a bunch of tests.

Closing...