SimpleTest_excerpt.js

/*
 * Polls the clipboard waiting for the expected value. A known value different than
 * the expected value is put on the clipboard first (and also polled for) so we
 * can be sure the value we get isn't just the expected value because it was already
 * on the clipboard. This only uses the global clipboard and only for text/unicode
 * values.
 *
 * @param aExpectedVal
 *        The string value that is expected to be on the clipboard
 * @param aSetupFn
 *        A function responsible for setting the clipboard to the expected value,
 *        called after the known value setting succeeds.
 * @param aSuccessFn
 *        A function called when the expected value is found on the clipboard.
 * @param aFailureFn
 *        A function called if the expected value isn't found on the clipboard
 *        within 5s. It can also be called if the known value can't be found.
 */
SimpleTest.waitForClipboard = function(aExpectedVal, aSetupFn, aSuccessFn, aFailureFn) {

waitForClipboard_sample.js

function test() {
  waitForExplicitFinish();

  // the value we expect to be on the clipboard
  const EXPECTED_VAL = "foo";

  // function that will set up the clipboard
  function setup() {
    Cc["@mozilla.org/widget/clipboardhelper;1"].
    getService(Ci.nsIClipboardHelper).
    copyString(EXPECTED_VAL);
  }

  // function that will be run after the clipboard has EXPECTED_VAL
  function nextTest() {
    // do some other testing here if you want
    finish();
  }

  waitForClipboard(EXPECTED_VAL, setup, nextTest, finish);
}