/**
 * @license
 * 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.
 */
import '../../../test/common-test-setup-karma.js';
import {getMockDiffResponse} from '../../../test/mocks/diff-response.js';
import './gr-diff-builder-element.js';
import {stubBaseUrl} from '../../../test/test-utils.js';
import {flush} from '@polymer/polymer/lib/legacy/polymer.dom.js';
import {GrAnnotation} from '../gr-diff-highlight/gr-annotation.js';
import {GrDiffLine, GrDiffLineType} from '../gr-diff/gr-diff-line.js';
import {GrDiffGroup, GrDiffGroupType} from '../gr-diff/gr-diff-group.js';
import {GrDiffBuilder} from './gr-diff-builder.js';
import {GrDiffBuilderSideBySide} from './gr-diff-builder-side-by-side.js';
import {html} from '@polymer/polymer/lib/utils/html-tag.js';
import {DiffViewMode, Side} from '../../../api/diff.js';
import {stubRestApi} from '../../../test/test-utils.js';
import {afterNextRender} from '@polymer/polymer/lib/utils/render-status';
import {GrDiffBuilderLegacy} from './gr-diff-builder-legacy.js';

const basicFixture = fixtureFromTemplate(html`
    <gr-diff-builder>
      <table id="diffTable"></table>
    </gr-diff-builder>
`);

const divWithTextFixture = fixtureFromTemplate(html`
<div>Lorem ipsum dolor sit amet, suspendisse inceptos vehicula</div>
`);

const mockDiffFixture = fixtureFromTemplate(html`
<gr-diff-builder view-mode="SIDE_BY_SIDE">
      <table id="diffTable"></table>
    </gr-diff-builder>
`);

// GrDiffBuilderElement forces these prefs to be set - tests that do not care
// about these values can just set these defaults.
const DEFAULT_PREFS = {
  line_length: 10,
  show_tabs: true,
  tab_size: 4,
};

suite('gr-diff-builder tests', () => {
  let prefs;
  let element;
  let builder;

  const LINE_BREAK_HTML = '<span class="style-scope gr-diff br"></span>';
  const WBR_HTML = '<wbr class="style-scope gr-diff">';

  setup(() => {
    element = basicFixture.instantiate();
    stubRestApi('getLoggedIn').returns(Promise.resolve(false));
    stubRestApi('getProjectConfig').returns(Promise.resolve({}));
    stubBaseUrl('/r');
    prefs = {...DEFAULT_PREFS};
    builder = new GrDiffBuilderLegacy({content: []}, prefs);
  });

  test('line_length applied with <wbr> if line_wrapping is true', () => {
    builder._prefs = {line_wrapping: true, tab_size: 4, line_length: 50};
    const text = 'a'.repeat(51);

    const line = {text, highlights: []};
    const expected = 'a'.repeat(50) + WBR_HTML + 'a';
    const result = builder.createTextEl(undefined, line).firstChild.innerHTML;
    assert.equal(result, expected);
  });

  test('line_length applied with line break if line_wrapping is false', () => {
    builder._prefs = {line_wrapping: false, tab_size: 4, line_length: 50};
    const text = 'a'.repeat(51);

    const line = {text, highlights: []};
    const expected = 'a'.repeat(50) + LINE_BREAK_HTML + 'a';
    const result = builder.createTextEl(undefined, line).firstChild.innerHTML;
    assert.equal(result, expected);
  });

  [DiffViewMode.UNIFIED, DiffViewMode.SIDE_BY_SIDE]
      .forEach(mode => {
        test(`line_length used for regular files under ${mode}`, () => {
          element.path = '/a.txt';
          element.viewMode = mode;
          element.diff = {};
          element.prefs = {tab_size: 4, line_length: 50};
          builder = element._getDiffBuilder();
          assert.equal(builder._prefs.line_length, 50);
        });

        test(`line_length ignored for commit msg under ${mode}`, () => {
          element.path = '/COMMIT_MSG';
          element.viewMode = mode;
          element.diff = {};
          element.prefs = {tab_size: 4, line_length: 50};
          builder = element._getDiffBuilder();
          assert.equal(builder._prefs.line_length, 72);
        });
      });

  test('createTextEl linewrap with tabs', () => {
    const text = '\t'.repeat(7) + '!';
    const line = {text, highlights: []};
    const el = builder.createTextEl(undefined, line);
    assert.equal(el.innerText, text);
    // With line length 10 and tab size 2, there should be a line break
    // after every two tabs.
    const newlineEl = el.querySelector('.contentText > .br');
    assert.isOk(newlineEl);
    assert.equal(
        el.querySelector('.contentText .tab:nth-child(2)').nextSibling,
        newlineEl);
  });

  test('_handlePreferenceError throws with invalid preference', () => {
    element.prefs = {tab_size: 0};
    assert.throws(() => element._getDiffBuilder());
  });

  test('_handlePreferenceError triggers alert and javascript error', () => {
    const errorStub = sinon.stub();
    element.addEventListener('show-alert', errorStub);
    assert.throws(() => element._handlePreferenceError('tab size'));
    assert.equal(errorStub.lastCall.args[0].detail.message,
        `The value of the 'tab size' user preference is invalid. ` +
      `Fix in diff preferences`);
  });

  suite('isTotal', () => {
    test('is total for add', () => {
      const lines = [];
      for (let idx = 0; idx < 10; idx++) {
        lines.push(new GrDiffLine(GrDiffLineType.ADD));
      }
      const group = new GrDiffGroup({type: GrDiffGroupType.DELTA, lines});
      assert.isTrue(GrDiffBuilder.prototype.isTotal(group));
    });

    test('is total for remove', () => {
      const lines = [];
      for (let idx = 0; idx < 10; idx++) {
        lines.push(new GrDiffLine(GrDiffLineType.REMOVE));
      }
      const group = new GrDiffGroup({type: GrDiffGroupType.DELTA, lines});
      assert.isTrue(GrDiffBuilder.prototype.isTotal(group));
    });

    test('not total for empty', () => {
      const group = new GrDiffGroup({type: GrDiffGroupType.BOTH});
      assert.isFalse(GrDiffBuilder.prototype.isTotal(group));
    });

    test('not total for non-delta', () => {
      const lines = [];
      for (let idx = 0; idx < 10; idx++) {
        lines.push(new GrDiffLine(GrDiffLineType.BOTH));
      }
      const group = new GrDiffGroup({type: GrDiffGroupType.DELTA, lines});
      assert.isFalse(GrDiffBuilder.prototype.isTotal(group));
    });
  });

  suite('intraline differences', () => {
    let el;
    let str;
    let annotateElementSpy;
    let layer;
    const lineNumberEl = document.createElement('td');

    function slice(str, start, end) {
      return Array.from(str).slice(start, end)
          .join('');
    }

    setup(() => {
      el = divWithTextFixture.instantiate();
      str = el.textContent;
      annotateElementSpy = sinon.spy(GrAnnotation, 'annotateElement');
      layer = document.createElement('gr-diff-builder')
          ._createIntralineLayer();
    });

    test('annotate no highlights', () => {
      const line = {
        text: str,
        highlights: [],
      };

      layer.annotate(el, lineNumberEl, line);

      // The content is unchanged.
      assert.isFalse(annotateElementSpy.called);
      assert.equal(el.childNodes.length, 1);
      assert.instanceOf(el.childNodes[0], Text);
      assert.equal(str, el.childNodes[0].textContent);
    });

    test('annotate with highlights', () => {
      const line = {
        text: str,
        highlights: [
          {startIndex: 6, endIndex: 12},
          {startIndex: 18, endIndex: 22},
        ],
      };
      const str0 = slice(str, 0, 6);
      const str1 = slice(str, 6, 12);
      const str2 = slice(str, 12, 18);
      const str3 = slice(str, 18, 22);
      const str4 = slice(str, 22);

      layer.annotate(el, lineNumberEl, line);

      assert.isTrue(annotateElementSpy.called);
      assert.equal(el.childNodes.length, 5);

      assert.instanceOf(el.childNodes[0], Text);
      assert.equal(el.childNodes[0].textContent, str0);

      assert.notInstanceOf(el.childNodes[1], Text);
      assert.equal(el.childNodes[1].textContent, str1);

      assert.instanceOf(el.childNodes[2], Text);
      assert.equal(el.childNodes[2].textContent, str2);

      assert.notInstanceOf(el.childNodes[3], Text);
      assert.equal(el.childNodes[3].textContent, str3);

      assert.instanceOf(el.childNodes[4], Text);
      assert.equal(el.childNodes[4].textContent, str4);
    });

    test('annotate without endIndex', () => {
      const line = {
        text: str,
        highlights: [
          {startIndex: 28},
        ],
      };

      const str0 = slice(str, 0, 28);
      const str1 = slice(str, 28);

      layer.annotate(el, lineNumberEl, line);

      assert.isTrue(annotateElementSpy.called);
      assert.equal(el.childNodes.length, 2);

      assert.instanceOf(el.childNodes[0], Text);
      assert.equal(el.childNodes[0].textContent, str0);

      assert.notInstanceOf(el.childNodes[1], Text);
      assert.equal(el.childNodes[1].textContent, str1);
    });

    test('annotate ignores empty highlights', () => {
      const line = {
        text: str,
        highlights: [
          {startIndex: 28, endIndex: 28},
        ],
      };

      layer.annotate(el, lineNumberEl, line);

      assert.isFalse(annotateElementSpy.called);
      assert.equal(el.childNodes.length, 1);
    });

    test('annotate handles unicode', () => {
      // Put some unicode into the string:
      str = str.replace(/\s/g, '💢');
      el.textContent = str;
      const line = {
        text: str,
        highlights: [
          {startIndex: 6, endIndex: 12},
        ],
      };

      const str0 = slice(str, 0, 6);
      const str1 = slice(str, 6, 12);
      const str2 = slice(str, 12);

      layer.annotate(el, lineNumberEl, line);

      assert.isTrue(annotateElementSpy.called);
      assert.equal(el.childNodes.length, 3);

      assert.instanceOf(el.childNodes[0], Text);
      assert.equal(el.childNodes[0].textContent, str0);

      assert.notInstanceOf(el.childNodes[1], Text);
      assert.equal(el.childNodes[1].textContent, str1);

      assert.instanceOf(el.childNodes[2], Text);
      assert.equal(el.childNodes[2].textContent, str2);
    });

    test('annotate handles unicode w/o endIndex', () => {
      // Put some unicode into the string:
      str = str.replace(/\s/g, '💢');
      el.textContent = str;

      const line = {
        text: str,
        highlights: [
          {startIndex: 6},
        ],
      };

      const str0 = slice(str, 0, 6);
      const str1 = slice(str, 6);

      layer.annotate(el, lineNumberEl, line);

      assert.isTrue(annotateElementSpy.called);
      assert.equal(el.childNodes.length, 2);

      assert.instanceOf(el.childNodes[0], Text);
      assert.equal(el.childNodes[0].textContent, str0);

      assert.notInstanceOf(el.childNodes[1], Text);
      assert.equal(el.childNodes[1].textContent, str1);
    });
  });

  suite('tab indicators', () => {
    let element;
    let layer;
    const lineNumberEl = document.createElement('td');

    setup(() => {
      element = basicFixture.instantiate();
      element._showTabs = true;
      layer = element._createTabIndicatorLayer();
    });

    test('does nothing with empty line', () => {
      const line = {text: ''};
      const el = document.createElement('div');
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');

      layer.annotate(el, lineNumberEl, line);

      assert.isFalse(annotateElementStub.called);
    });

    test('does nothing with no tabs', () => {
      const str = 'lorem ipsum no tabs';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');

      layer.annotate(el, lineNumberEl, line);

      assert.isFalse(annotateElementStub.called);
    });

    test('annotates tab at beginning', () => {
      const str = '\tlorem upsum';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');

      layer.annotate(el, lineNumberEl, line);

      assert.equal(annotateElementStub.callCount, 1);
      const args = annotateElementStub.getCalls()[0].args;
      assert.equal(args[0], el);
      assert.equal(args[1], 0, 'offset of tab indicator');
      assert.equal(args[2], 1, 'length of tab indicator');
      assert.include(args[3], 'tab-indicator');
    });

    test('does not annotate when disabled', () => {
      element._showTabs = false;

      const str = '\tlorem upsum';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');

      layer.annotate(el, lineNumberEl, line);

      assert.isFalse(annotateElementStub.called);
    });

    test('annotates multiple in beginning', () => {
      const str = '\t\tlorem upsum';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');

      layer.annotate(el, lineNumberEl, line);

      assert.equal(annotateElementStub.callCount, 2);

      let args = annotateElementStub.getCalls()[0].args;
      assert.equal(args[0], el);
      assert.equal(args[1], 0, 'offset of tab indicator');
      assert.equal(args[2], 1, 'length of tab indicator');
      assert.include(args[3], 'tab-indicator');

      args = annotateElementStub.getCalls()[1].args;
      assert.equal(args[0], el);
      assert.equal(args[1], 1, 'offset of tab indicator');
      assert.equal(args[2], 1, 'length of tab indicator');
      assert.include(args[3], 'tab-indicator');
    });

    test('annotates intermediate tabs', () => {
      const str = 'lorem\tupsum';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');

      layer.annotate(el, lineNumberEl, line);

      assert.equal(annotateElementStub.callCount, 1);
      const args = annotateElementStub.getCalls()[0].args;
      assert.equal(args[0], el);
      assert.equal(args[1], 5, 'offset of tab indicator');
      assert.equal(args[2], 1, 'length of tab indicator');
      assert.include(args[3], 'tab-indicator');
    });
  });

  suite('layers', () => {
    let element;
    let initialLayersCount;
    let withLayerCount;
    setup(() => {
      const layers = [];
      element = basicFixture.instantiate();
      element.layers = layers;
      element._showTrailingWhitespace = true;
      element._setupAnnotationLayers();
      initialLayersCount = element._layers.length;
    });

    test('no layers', () => {
      element._setupAnnotationLayers();
      assert.equal(element._layers.length, initialLayersCount);
    });

    suite('with layers', () => {
      const layers = [{}, {}];
      setup(() => {
        element = basicFixture.instantiate();
        element.layers = layers;
        element._showTrailingWhitespace = true;
        element._setupAnnotationLayers();
        withLayerCount = element._layers.length;
      });
      test('with layers', () => {
        element._setupAnnotationLayers();
        assert.equal(element._layers.length, withLayerCount);
        assert.equal(initialLayersCount + layers.length,
            withLayerCount);
      });
    });
  });

  suite('trailing whitespace', () => {
    let element;
    let layer;
    const lineNumberEl = document.createElement('td');

    setup(() => {
      element = basicFixture.instantiate();
      element._showTrailingWhitespace = true;
      layer = element._createTrailingWhitespaceLayer();
    });

    test('does nothing with empty line', () => {
      const line = {text: ''};
      const el = document.createElement('div');
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');
      layer.annotate(el, lineNumberEl, line);
      assert.isFalse(annotateElementStub.called);
    });

    test('does nothing with no trailing whitespace', () => {
      const str = 'lorem ipsum blah blah';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');
      layer.annotate(el, lineNumberEl, line);
      assert.isFalse(annotateElementStub.called);
    });

    test('annotates trailing spaces', () => {
      const str = 'lorem ipsum   ';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');
      layer.annotate(el, lineNumberEl, line);
      assert.isTrue(annotateElementStub.called);
      assert.equal(annotateElementStub.lastCall.args[1], 11);
      assert.equal(annotateElementStub.lastCall.args[2], 3);
    });

    test('annotates trailing tabs', () => {
      const str = 'lorem ipsum\t\t\t';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');
      layer.annotate(el, lineNumberEl, line);
      assert.isTrue(annotateElementStub.called);
      assert.equal(annotateElementStub.lastCall.args[1], 11);
      assert.equal(annotateElementStub.lastCall.args[2], 3);
    });

    test('annotates mixed trailing whitespace', () => {
      const str = 'lorem ipsum\t \t';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');
      layer.annotate(el, lineNumberEl, line);
      assert.isTrue(annotateElementStub.called);
      assert.equal(annotateElementStub.lastCall.args[1], 11);
      assert.equal(annotateElementStub.lastCall.args[2], 3);
    });

    test('unicode preceding trailing whitespace', () => {
      const str = '💢\t';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');
      layer.annotate(el, lineNumberEl, line);
      assert.isTrue(annotateElementStub.called);
      assert.equal(annotateElementStub.lastCall.args[1], 1);
      assert.equal(annotateElementStub.lastCall.args[2], 1);
    });

    test('does not annotate when disabled', () => {
      element._showTrailingWhitespace = false;
      const str = 'lorem upsum\t \t ';
      const line = {text: str};
      const el = document.createElement('div');
      el.textContent = str;
      const annotateElementStub =
          sinon.stub(GrAnnotation, 'annotateElement');
      layer.annotate(el, lineNumberEl, line);
      assert.isFalse(annotateElementStub.called);
    });
  });

  suite('rendering text, images and binary files', () => {
    let processStub;
    let keyLocations;
    let content;

    setup(() => {
      element = basicFixture.instantiate();
      element.viewMode = 'SIDE_BY_SIDE';
      processStub = sinon.stub(element.$.processor, 'process')
          .returns(Promise.resolve());
      keyLocations = {left: {}, right: {}};
      element.prefs = {
        ...DEFAULT_PREFS,
        context: -1,
        syntax_highlighting: true,
      };
      content = [{
        a: ['all work and no play make andybons a dull boy'],
        b: ['elgoog elgoog elgoog'],
      }, {
        ab: [
          'Non eram nescius, Brute, cum, quae summis ingeniis ',
          'exquisitaque doctrina philosophi Graeco sermone tractavissent',
        ],
      }];
    });

    test('text', () => {
      element.diff = {content};
      return element.render(keyLocations).then(() => {
        assert.isTrue(processStub.calledOnce);
        assert.isFalse(processStub.lastCall.args[1]);
      });
    });

    test('image', () => {
      element.diff = {content, binary: true};
      element.isImageDiff = true;
      return element.render(keyLocations).then(() => {
        assert.isTrue(processStub.calledOnce);
        assert.isTrue(processStub.lastCall.args[1]);
      });
    });

    test('binary', () => {
      element.diff = {content, binary: true};
      return element.render(keyLocations).then(() => {
        assert.isTrue(processStub.calledOnce);
        assert.isTrue(processStub.lastCall.args[1]);
      });
    });
  });

  suite('rendering', () => {
    let content;
    let outputEl;
    let keyLocations;

    setup(async () => {
      const prefs = {...DEFAULT_PREFS};
      content = [
        {
          a: ['all work and no play make andybons a dull boy'],
          b: ['elgoog elgoog elgoog'],
        },
        {
          ab: [
            'Non eram nescius, Brute, cum, quae summis ingeniis ',
            'exquisitaque doctrina philosophi Graeco sermone tractavissent',
          ],
        },
      ];
      element = basicFixture.instantiate();
      sinon.stub(element, 'dispatchEvent');
      outputEl = element.querySelector('#diffTable');
      keyLocations = {left: {}, right: {}};
      sinon.stub(element, '_getDiffBuilder').callsFake(() => {
        const builder = new GrDiffBuilderSideBySide({content}, prefs, outputEl);
        sinon.stub(builder, 'addColumns');
        builder.buildSectionElement = function(group) {
          const section = document.createElement('stub');
          section.textContent = group.lines
              .reduce((acc, line) => acc + line.text, '');
          return section;
        };
        return builder;
      });
      element.diff = {content};
      element.prefs = prefs;
      await element.render(keyLocations);
    });

    test('addColumns is called', () => {
      assert.isTrue(element._builder.addColumns.called);
    });

    test('getGroupsByLineRange one line', () => {
      const section = outputEl.querySelector('stub:nth-of-type(3)');
      const groups = element._builder.getGroupsByLineRange(1, 1, 'left');
      assert.equal(groups.length, 1);
      assert.strictEqual(groups[0].element, section);
    });

    test('getGroupsByLineRange over diff', () => {
      const section = [
        outputEl.querySelector('stub:nth-of-type(3)'),
        outputEl.querySelector('stub:nth-of-type(4)'),
      ];
      const groups = element._builder.getGroupsByLineRange(1, 2, 'left');
      assert.equal(groups.length, 2);
      assert.strictEqual(groups[0].element, section[0]);
      assert.strictEqual(groups[1].element, section[1]);
    });

    test('render-start and render-content are fired', async () => {
      const firedEventTypes = element.dispatchEvent.getCalls()
          .map(c => c.args[0].type);
      assert.include(firedEventTypes, 'render-start');
      assert.include(firedEventTypes, 'render-content');
    });

    test('cancel cancels the processor', () => {
      const processorCancelStub = sinon.stub(element.$.processor, 'cancel');
      element.cancel();
      assert.isTrue(processorCancelStub.called);
    });
  });

  suite('context hiding and expanding', () => {
    setup(async () => {
      element = basicFixture.instantiate();
      sinon.stub(element, 'dispatchEvent');
      const afterNextRenderPromise = new Promise((resolve, reject) => {
        afterNextRender(element, resolve);
      });
      element.diff = {
        content: [
          {ab: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].map(i => `unchanged ${i}`)},
          {a: ['before'], b: ['after']},
          {ab: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].map(i => `unchanged ${10 + i}`)},
        ],
      };
      element.viewMode = DiffViewMode.SIDE_BY_SIDE;

      const keyLocations = {left: {}, right: {}};
      element.prefs = {
        ...DEFAULT_PREFS,
        context: 1,
      };
      await element.render(keyLocations);
      // Make sure all listeners are installed.
      await afterNextRenderPromise;
    });

    test('hides lines behind two context controls', () => {
      const contextControls = element.querySelectorAll('gr-context-controls');
      assert.equal(contextControls.length, 2);

      const diffRows = element.querySelectorAll('.diff-row');
      // The first two are LOST and FILE line
      assert.equal(diffRows.length, 2 + 1 + 1 + 1);
      assert.include(diffRows[2].textContent, 'unchanged 10');
      assert.include(diffRows[3].textContent, 'before');
      assert.include(diffRows[3].textContent, 'after');
      assert.include(diffRows[4].textContent, 'unchanged 11');
    });

    test('clicking +x common lines expands those lines', () => {
      const contextControls = element.querySelectorAll('gr-context-controls');
      const topExpandCommonButton = contextControls[0].shadowRoot
          .querySelectorAll('.showContext')[0];
      assert.include(topExpandCommonButton.textContent, '+9 common lines');
      topExpandCommonButton.click();
      const diffRows = element.querySelectorAll('.diff-row');
      // The first two are LOST and FILE line
      assert.equal(diffRows.length, 2 + 10 + 1 + 1);
      assert.include(diffRows[2].textContent, 'unchanged 1');
      assert.include(diffRows[3].textContent, 'unchanged 2');
      assert.include(diffRows[4].textContent, 'unchanged 3');
      assert.include(diffRows[5].textContent, 'unchanged 4');
      assert.include(diffRows[6].textContent, 'unchanged 5');
      assert.include(diffRows[7].textContent, 'unchanged 6');
      assert.include(diffRows[8].textContent, 'unchanged 7');
      assert.include(diffRows[9].textContent, 'unchanged 8');
      assert.include(diffRows[10].textContent, 'unchanged 9');
      assert.include(diffRows[11].textContent, 'unchanged 10');
      assert.include(diffRows[12].textContent, 'before');
      assert.include(diffRows[12].textContent, 'after');
      assert.include(diffRows[13].textContent, 'unchanged 11');
    });

    test('unhideLine shows the line with context', async () => {
      const clock = sinon.useFakeTimers();
      element.dispatchEvent.reset();
      element.unhideLine(4, Side.LEFT);

      const diffRows = element.querySelectorAll('.diff-row');
      // The first two are LOST and FILE line
      // Lines 3-5 (Line 4 plus 1 context in each direction) will be expanded
      // Because context expanders do not hide <3 lines, lines 1-2 will also
      // be shown.
      // Lines 6-9 continue to be hidden
      assert.equal(diffRows.length, 2 + 5 + 1 + 1 + 1);
      assert.include(diffRows[2].textContent, 'unchanged 1');
      assert.include(diffRows[3].textContent, 'unchanged 2');
      assert.include(diffRows[4].textContent, 'unchanged 3');
      assert.include(diffRows[5].textContent, 'unchanged 4');
      assert.include(diffRows[6].textContent, 'unchanged 5');
      assert.include(diffRows[7].textContent, 'unchanged 10');
      assert.include(diffRows[8].textContent, 'before');
      assert.include(diffRows[8].textContent, 'after');
      assert.include(diffRows[9].textContent, 'unchanged 11');

      clock.tick(1);
      await flush();
      const firedEventTypes = element.dispatchEvent.getCalls()
          .map(c => c.args[0].type);
      assert.include(firedEventTypes, 'render-content');
    });
  });

  suite('mock-diff', () => {
    let element;
    let builder;
    let diff;
    let keyLocations;

    setup(async () => {
      element = mockDiffFixture.instantiate();
      diff = getMockDiffResponse();
      element.diff = diff;

      keyLocations = {left: {}, right: {}};

      element.prefs = {
        line_length: 80,
        show_tabs: true,
        tab_size: 4,
      };
      await element.render(keyLocations);
      builder = element._builder;
    });

    test('aria-labels on added line numbers', () => {
      const deltaLineNumberButton = element.diffElement.querySelectorAll(
          '.lineNumButton.right')[5];

      assert.isOk(deltaLineNumberButton);
      assert.equal(deltaLineNumberButton.getAttribute('aria-label'), '5 added');
    });

    test('aria-labels on removed line numbers', () => {
      const deltaLineNumberButton = element.diffElement.querySelectorAll(
          '.lineNumButton.left')[10];

      assert.isOk(deltaLineNumberButton);
      assert.equal(
          deltaLineNumberButton.getAttribute('aria-label'), '10 removed');
    });

    test('getContentByLine', () => {
      let actual;

      actual = builder.getContentByLine(2, 'left');
      assert.equal(actual.textContent, diff.content[0].ab[1]);

      actual = builder.getContentByLine(2, 'right');
      assert.equal(actual.textContent, diff.content[0].ab[1]);

      actual = builder.getContentByLine(5, 'left');
      assert.equal(actual.textContent, diff.content[2].ab[0]);

      actual = builder.getContentByLine(5, 'right');
      assert.equal(actual.textContent, diff.content[1].b[0]);
    });

    test('getContentTdByLineEl works both with button and td', () => {
      const diffRow = element.diffElement.querySelectorAll('tr.diff-row')[2];

      const lineNumTdLeft = diffRow.querySelector('td.lineNum.left');
      const lineNumButtonLeft = lineNumTdLeft.querySelector('button');
      const contentTdLeft = diffRow.querySelectorAll('.content')[0];

      const lineNumTdRight = diffRow.querySelector('td.lineNum.right');
      const lineNumButtonRight = lineNumTdRight.querySelector('button');
      const contentTdRight = diffRow.querySelectorAll('.content')[1];

      assert.equal(element.getContentTdByLineEl(lineNumTdLeft), contentTdLeft);
      assert.equal(
          element.getContentTdByLineEl(lineNumButtonLeft), contentTdLeft);
      assert.equal(
          element.getContentTdByLineEl(lineNumTdRight), contentTdRight);
      assert.equal(
          element.getContentTdByLineEl(lineNumButtonRight), contentTdRight);
    });

    test('findLinesByRange', () => {
      const lines = [];
      const elems = [];
      const start = 6;
      const end = 10;
      const count = end - start + 1;

      builder.findLinesByRange(start, end, 'right', lines, elems);

      assert.equal(lines.length, count);
      assert.equal(elems.length, count);

      for (let i = 0; i < 5; i++) {
        assert.instanceOf(lines[i], GrDiffLine);
        assert.equal(lines[i].afterNumber, start + i);
        assert.instanceOf(elems[i], HTMLElement);
        assert.equal(lines[i].text, elems[i].textContent);
      }
    });

    test('renderContentByRange', () => {
      const spy = sinon.spy(builder, 'createTextEl');
      const start = 9;
      const end = 14;
      const count = end - start + 1;

      builder.renderContentByRange(start, end, 'left');

      assert.equal(spy.callCount, count);
      spy.getCalls().forEach((call, i) => {
        assert.equal(call.args[1].beforeNumber, start + i);
      });
    });

    test('renderContentByRange notexistent elements', () => {
      const spy = sinon.spy(builder, 'createTextEl');

      sinon.stub(builder, 'getLineNumberEl').returns(
          document.createElement('div')
      );
      sinon.stub(builder, 'findLinesByRange').callsFake(
          (s, e, d, lines, elements) => {
            // Add a line and a corresponding element.
            lines.push(new GrDiffLine(GrDiffLineType.BOTH));
            const tr = document.createElement('tr');
            const td = document.createElement('td');
            const el = document.createElement('div');
            tr.appendChild(td);
            td.appendChild(el);
            elements.push(el);

            // Add 2 lines without corresponding elements.
            lines.push(new GrDiffLine(GrDiffLineType.BOTH));
            lines.push(new GrDiffLine(GrDiffLineType.BOTH));
          });

      builder.renderContentByRange(1, 10, 'left');
      // Should be called only once because only one line had a corresponding
      // element.
      assert.equal(spy.callCount, 1);
    });

    test('getLineNumberEl side-by-side left', () => {
      const contentEl = builder.getContentByLine(5, 'left',
          element.$.diffTable);
      const lineNumberEl = builder.getLineNumberEl(contentEl, 'left');
      assert.isTrue(lineNumberEl.classList.contains('lineNum'));
      assert.isTrue(lineNumberEl.classList.contains('left'));
    });

    test('getLineNumberEl side-by-side right', () => {
      const contentEl = builder.getContentByLine(5, 'right',
          element.$.diffTable);
      const lineNumberEl = builder.getLineNumberEl(contentEl, 'right');
      assert.isTrue(lineNumberEl.classList.contains('lineNum'));
      assert.isTrue(lineNumberEl.classList.contains('right'));
    });

    test('getLineNumberEl unified left', async () => {
      // Re-render as unified:
      element.viewMode = 'UNIFIED_DIFF';
      await element.render(keyLocations);
      builder = element._builder;

      const contentEl = builder.getContentByLine(5, 'left',
          element.$.diffTable);
      const lineNumberEl = builder.getLineNumberEl(contentEl, 'left');
      assert.isTrue(lineNumberEl.classList.contains('lineNum'));
      assert.isTrue(lineNumberEl.classList.contains('left'));
    });

    test('getLineNumberEl unified right', async () => {
      // Re-render as unified:
      element.viewMode = 'UNIFIED_DIFF';
      await element.render(keyLocations);
      builder = element._builder;

      const contentEl = builder.getContentByLine(5, 'right',
          element.$.diffTable);
      const lineNumberEl = builder.getLineNumberEl(contentEl, 'right');
      assert.isTrue(lineNumberEl.classList.contains('lineNum'));
      assert.isTrue(lineNumberEl.classList.contains('right'));
    });

    test('getNextContentOnSide side-by-side left', () => {
      const startElem = builder.getContentByLine(5, 'left',
          element.$.diffTable);
      const expectedStartString = diff.content[2].ab[0];
      const expectedNextString = diff.content[2].ab[1];
      assert.equal(startElem.textContent, expectedStartString);

      const nextElem = builder.getNextContentOnSide(startElem,
          'left');
      assert.equal(nextElem.textContent, expectedNextString);
    });

    test('getNextContentOnSide side-by-side right', () => {
      const startElem = builder.getContentByLine(5, 'right',
          element.$.diffTable);
      const expectedStartString = diff.content[1].b[0];
      const expectedNextString = diff.content[1].b[1];
      assert.equal(startElem.textContent, expectedStartString);

      const nextElem = builder.getNextContentOnSide(startElem,
          'right');
      assert.equal(nextElem.textContent, expectedNextString);
    });

    test('getNextContentOnSide unified left', async () => {
      // Re-render as unified:
      element.viewMode = 'UNIFIED_DIFF';
      await element.render(keyLocations);
      builder = element._builder;

      const startElem = builder.getContentByLine(5, 'left',
          element.$.diffTable);
      const expectedStartString = diff.content[2].ab[0];
      const expectedNextString = diff.content[2].ab[1];
      assert.equal(startElem.textContent, expectedStartString);

      const nextElem = builder.getNextContentOnSide(startElem,
          'left');
      assert.equal(nextElem.textContent, expectedNextString);
    });

    test('getNextContentOnSide unified right', async () => {
      // Re-render as unified:
      element.viewMode = 'UNIFIED_DIFF';
      await element.render(keyLocations);
      builder = element._builder;

      const startElem = builder.getContentByLine(5, 'right',
          element.$.diffTable);
      const expectedStartString = diff.content[1].b[0];
      const expectedNextString = diff.content[1].b[1];
      assert.equal(startElem.textContent, expectedStartString);

      const nextElem = builder.getNextContentOnSide(startElem,
          'right');
      assert.equal(nextElem.textContent, expectedNextString);
    });
  });

  suite('blame', () => {
    let mockBlame;

    setup(() => {
      mockBlame = [
        {id: 'commit 1', ranges: [{start: 1, end: 2}, {start: 10, end: 16}]},
        {id: 'commit 2', ranges: [{start: 4, end: 10}, {start: 17, end: 32}]},
      ];
    });

    test('setBlame attempts to render each blamed line', () => {
      const getBlameStub = sinon.stub(builder, 'getBlameTdByLine')
          .returns(null);
      builder.setBlame(mockBlame);
      assert.equal(getBlameStub.callCount, 32);
    });

    test('getBlameCommitForBaseLine', () => {
      sinon.stub(builder, 'getBlameTdByLine').returns(undefined);
      builder.setBlame(mockBlame);
      assert.isOk(builder.getBlameCommitForBaseLine(1));
      assert.equal(builder.getBlameCommitForBaseLine(1).id, 'commit 1');

      assert.isOk(builder.getBlameCommitForBaseLine(11));
      assert.equal(builder.getBlameCommitForBaseLine(11).id, 'commit 1');

      assert.isOk(builder.getBlameCommitForBaseLine(32));
      assert.equal(builder.getBlameCommitForBaseLine(32).id, 'commit 2');

      assert.isUndefined(builder.getBlameCommitForBaseLine(33));
    });

    test('getBlameCommitForBaseLine w/o blame returns null', () => {
      assert.isUndefined(builder.getBlameCommitForBaseLine(1));
      assert.isUndefined(builder.getBlameCommitForBaseLine(11));
      assert.isUndefined(builder.getBlameCommitForBaseLine(31));
    });

    test('createBlameCell', () => {
      const mockBlameInfo = {
        time: 1576155200,
        id: 1234567890,
        author: 'Clark Kent',
        commit_msg: 'Testing Commit',
        ranges: [1],
      };
      const getBlameStub = sinon.stub(builder, 'getBlameCommitForBaseLine')
          .returns(mockBlameInfo);
      const line = new GrDiffLine(GrDiffLineType.BOTH);
      line.beforeNumber = 3;
      line.afterNumber = 5;

      const result = builder.createBlameCell(line.beforeNumber);

      assert.isTrue(getBlameStub.calledWithExactly(3));
      assert.equal(result.getAttribute('data-line-number'), '3');
      expect(result).dom.to.equal(/* HTML */`
        <span class="gr-diff style-scope">
          <a class="blameDate gr-diff style-scope" href="/r/q/1234567890">
            12/12/2019
          </a>
          <span class="blameAuthor gr-diff style-scope">Clark</span>
          <gr-hovercard class="gr-diff style-scope">
            <span class="blameHoverCard gr-diff style-scope">
              Commit 1234567890<br>
              Author: Clark Kent<br>
              Date: 12/12/2019<br>
              <br>
              Testing Commit
            </span>
          </gr-hovercard>
        </span>
      `);
    });
  });
});