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<meta name="viewport" content="width=device-width, minimum-scale=1.0, initial-scale=1.0, user-scalable=yes">
<title>gr-syntax-lib-loader</title>

<script src="../../../bower_components/webcomponentsjs/webcomponents-lite.min.js"></script>
<script src="../../../bower_components/web-component-tester/browser.js"></script>

<link rel="import" href="gr-syntax-lib-loader.html">

<script>void(0);</script>

<test-fixture id="basic">
  <template>
    <gr-syntax-lib-loader></gr-syntax-lib-loader>
  </template>
</test-fixture>

<script>
  suite('gr-syntax-lib-loader tests', () => {
    let element;
    let resolveLoad;
    let loadStub;

    setup(() => {
      element = fixture('basic');

      loadStub = sinon.stub(element, '_loadHLJS', () =>
        new Promise(resolve => resolveLoad = resolve)
      );

      // Assert preconditions:
      assert.isFalse(element._state.loaded);
      assert.isFalse(element._state.loading);
    });

    teardown(() => {
      if (window.hljs) {
        delete window.hljs;
      }
      loadStub.restore();

      // Because the element state is a singleton, clean it up.
      element._state.loading = false;
      element._state.loaded = false;
      element._state.callbacks = [];
    });

    test('only load once', done => {
      const firstCallHandler = sinon.stub();
      element.get().then(firstCallHandler);

      // It should now be in the loading state.
      assert.isTrue(loadStub.called);
      assert.isTrue(element._state.loading);
      assert.isFalse(element._state.loaded);
      assert.isFalse(firstCallHandler.called);

      const secondCallHandler = sinon.stub();
      element.get().then(secondCallHandler);

      // No change in state.
      assert.isTrue(element._state.loading);
      assert.isFalse(element._state.loaded);
      assert.isFalse(firstCallHandler.called);
      assert.isFalse(secondCallHandler.called);

      // Now load the library.
      resolveLoad();
      flush(() => {
        // The state should be loaded and both handlers called.
        assert.isFalse(element._state.loading);
        assert.isTrue(element._state.loaded);
        assert.isTrue(firstCallHandler.called);
        assert.isTrue(secondCallHandler.called);
        done();
      });
    });
  });
</script>