<!DOCTYPE html>
<!--
Copyright (C) 2016 The Android Open Source Project

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->

<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="../../../test/common-test-setup.html"/>
<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>