function assertExtractedTextEquals(html, expectedText) {
  const actualText = textExtractor.extractTextContent(html);
  if (textExtractor.isSupported()) {
    assertEquals(actualText, expectedText);
  } else {
    assertEquals(actualText, '');
  }
}
Verifies that the expected text is extracted from the HTML string.
@param {string} html The HTML string containing text mixed in HTML markup.
@param {string} expectedText The expected text extracted from the HTML
string.