How to test Polymer Dart

Question

I started testing my web components and noticed that Dart has a good library for that and it does work well with Dart. But now I also want to test my Polymer component, but

Answer 1

You need proper Polymer initialization code. See how to implement a main function in polymer apps for details.

This package contains a lot of Polymer.dart unit tests you can use as example https://github.com/dart-lang/core-elements/tree/master/test

  import "../../../components/medium/bar-chart.dart";
  import "package:unittest/unittest.dart";
  import 'package:polymer/polymer.dart';
  import 'dart:html';

  main() {
    // old initPolymer().run(() {
    initPolymer().then((zone) => zone.run(() {
      print("--- Bar Chart Test ---");

      group('Bar Chart Test', () {
        test(("queryForBarChart"),() {
            expect(querySelector('bar-chart'), isNotNull); // PASS
        });

        test(("testtest"),() {
          // This should pass
          expect(querySelector('bar-chart').test(), equals(5));
          // Test failed: Caught type 'HtmlElement' is not a subtype of type 'BarChartElement' in type cast.
          // without Cast: Test failed: Caught Class 'HtmlElement' has no instance method 'test'.
        });
      });
    });
  }

Hint: don't forget to add the entry pages for the test to the polymer transformer configuation.