testStructure() {
    const emoji = spritedEmoji2;

    for (let i = 0; i < emoji[1].length; i++) {
      palette.setSelectedIndex(i);
      const emojiInfo = emoji[1][i];
      const cell = palette.getSelectedItem();
      const id = cell.getAttribute(Emoji.ATTRIBUTE);
      const inner = /** @type {Element} */ (cell.firstChild);

      // Check that the cell is a div wrapped around something else, and that
      // the outer div contains the goomoji attribute
      assertEquals(
          'The palette item should be a div wrapped around something',
          cell.tagName, 'DIV');
      assertNotNull(
          'The outer div is not wrapped around another element', inner);
      assertEquals(
          'The palette item should have the goomoji attribute',
          cell.getAttribute(Emoji.ATTRIBUTE), emojiInfo[1]);
      assertEquals(
          'The palette item should have the data-goomoji attribute',
          cell.getAttribute(Emoji.DATA_ATTRIBUTE), emojiInfo[1]);

      // Now check the contents of the cells
      const url = emojiInfo[0];  // url of the animated emoji
      const spriteInfo = emojiInfo[2];
      if (spriteInfo) {
        assertEquals(inner.tagName, 'DIV');
        if (spriteInfo.isAnimated()) {
          const img = images[id];
          checkPathsEndWithSameFile(
              style.getStyle(inner, 'background-image'), url);
          assertEquals(
              String(img.width),
              style.getStyle(inner, 'width')
                  .replace(/px/g, '')
                  .replace(/pt/g, ''));
          assertEquals(
              String(img.height),
              style.getStyle(inner, 'height')
                  .replace(/px/g, '')
                  .replace(/pt/g, ''));
          assertEquals(
              '0 0',
              style.getStyle(inner, 'background-position')
                  .replace(/px/g, '')
                  .replace(/pt/g, ''));
        } else {
          const cssClass = spriteInfo.getCssClass();
          if (cssClass) {
            assertTrue(
                'Sprite should have its CSS class set',
                classlist.contains(inner, cssClass));
          } else {
            checkPathsEndWithSameFile(
                style.getStyle(inner, 'background-image'), spriteInfo.getUrl());
            assertEquals(
                spriteInfo.getWidthCssValue(), style.getStyle(inner, 'width'));
            assertEquals(
                spriteInfo.getHeightCssValue(),
                style.getStyle(inner, 'height'));
            assertEquals(
                (spriteInfo.getXOffsetCssValue() + ' ' +
                 spriteInfo.getYOffsetCssValue())
                    .replace(/px/g, '')
                    .replace(/pt/g, ''),
                style.getStyle(inner, 'background-position')
                    .replace(/px/g, '')
                    .replace(/pt/g, ''));
          }
        }
      } else {
        // A non-sprited emoji is just an img
        assertEquals(inner.tagName, 'IMG');
        checkPathsEndWithSameFile(inner.src, emojiInfo[0]);
      }
    }
  }
Checks and verifies the structure of a non-progressive fast-loading picker
after the animated emoji have loaded.
@suppress {strictMissingProperties} suppression added to enable type
checking