

<!--

The `<test-fixture>` element can simplify the exercise of consistently
resetting a test suite's DOM. To use it, wrap the test suite's DOM as a template:

```html
<test-fixture id="SomeElementFixture">
  <template>
    <some-element id="SomeElementForTesting"></some-element>
  </template>
</test-fixture>
```

Now, the `<test-fixture>` element can be used to generate a copy of its
template:

```html
<script>
describe('<some-element>', function () {
  var someElement;

  beforeEach(function () {
    do