function waitForCondition(condition, nextTest, errorMsg) {
  var tries = 0;
  var interval = setInterval(function() {
    if (tries >= 30) {
      ok(false, errorMsg);
      moveOn();
    }
    if (condition()) {
      moveOn();
    }
    tries++;
  }, 100);
  var moveOn = function() { clearInterval(interval); nextTest(); };
}