fune/browser/base/content/test/general/browser_printpreview.js

let ourTab;

async function test() {
  waitForExplicitFinish();
  await pushPrefs(["print.tab_modal.enabled", false]);

  BrowserTestUtils.openNewForegroundTab(gBrowser, "about:home", true).then(
    function(tab) {
      ourTab = tab;
      ok(
        !gInPrintPreviewMode,
        "Should NOT be in print preview mode at starting this tests"
      );
      // Skip access key test on platforms which don't support access key.
      if (!/Win|Linux/.test(navigator.platform)) {
        openPrintPreview(testClosePrintPreviewWithEscKey);
      } else {
        openPrintPreview(testClosePrintPreviewWithAccessKey);
      }
    }
  );
}

function tidyUp() {
  BrowserTestUtils.removeTab(ourTab);
  finish();
}

async function testClosePrintPreviewWithAccessKey() {
  let closeButton = document.getElementById(
    "print-preview-toolbar-close-button"
  );
  await TestUtils.waitForCondition(() => closeButton.hasAttribute("accesskey"));
  EventUtils.synthesizeKey("c", { altKey: true });
  checkPrintPreviewClosed(function(aSucceeded) {
    ok(aSucceeded, "print preview mode should be finished by access key");
    openPrintPreview(testClosePrintPreviewWithEscKey);
  });
}

function testClosePrintPreviewWithEscKey() {
  EventUtils.synthesizeKey("KEY_Escape");
  checkPrintPreviewClosed(function(aSucceeded) {
    ok(aSucceeded, "print preview mode should be finished by Esc key press");
    openPrintPreview(testClosePrintPreviewWithClosingWindowShortcutKey);
  });
}

function testClosePrintPreviewWithClosingWindowShortcutKey() {
  EventUtils.synthesizeKey("w", { accelKey: true });
  checkPrintPreviewClosed(function(aSucceeded) {
    ok(
      aSucceeded,
      "print preview mode should be finished by closing window shortcut key"
    );
    tidyUp();
  });
}

function openPrintPreview(aCallback) {
  document.getElementById("cmd_printPreview").doCommand();
  executeSoon(function waitForPrintPreview() {
    if (gInPrintPreviewMode) {
      executeSoon(aCallback);
      return;
    }
    executeSoon(waitForPrintPreview);
  });
}

function checkPrintPreviewClosed(aCallback) {
  let count = 0;
  executeSoon(function waitForPrintPreviewClosed() {
    if (!gInPrintPreviewMode) {
      executeSoon(function() {
        aCallback(count < 1000);
      });
      return;
    }
    if (++count == 1000) {
      // The test might fail.
      PrintUtils.exitPrintPreview();
    }
    executeSoon(waitForPrintPreviewClosed);
  });
}