Function verifySelectorsVisible

build-system/tasks/visual-diff/verifiers.js:62–96

* Verifies that all CSS elements are as expected before taking a snapshot. * * @param {!puppeteer.Page} page a Puppeteer control browser tab/page. * @param {string} testName the full name of the test. * @param {!Array } selectors Array of CSS selectors that must * eventually appear o

(
  page,
  testName,
  selectors,
  timeoutMillis = CSS_SELECTOR_TIMEOUT_MS
)

 * @throws {Error} an encountered error.
 */
async function verifySelectorsVisible(
  page,
  testName,
  selectors,
  timeoutMillis = CSS_SELECTOR_TIMEOUT_MS
) {
  log('verbose', 'Waiting for existence of all:', cyan(selectors.join(', ')));
  try {
    await Promise.all(
      selectors.map((selector) =>
        waitForSelectorExistence(page, selector, timeoutMillis)
      )
    );
  } catch (e) {
    throw new Error(
      `${cyan(testName)} | The CSS selector ` +
        `${cyan(e.message)} does not match any elements in the page`
    );
  }

  log('verbose', 'Waiting for visibility of all:', cyan(selectors.join(', ')));
  try {
    await Promise.all(
      selectors.map((selector) =>
        waitForElementVisibility(page, selector, {visible: true}, timeoutMillis)
      )
    );
  } catch (e) {
    throw new Error(
      `${cyan(testName)} | An element with the CSS ` +
        `selector ${cyan(e.message)} is still invisible after ` +
        `${CSS_SELECTOR_TIMEOUT_MS} ms`
    );
  }
}

/**
 * Wait for all AMP loader indicators to disappear.