@Test
  public void shouldNotFindChildElementByCss() throws Exception {
    openStartActivity();
    WebElement rootElement = driver().findElement(By.id("l10n"));
    try {
      rootElement.findElement(By.cssSelector("button[id='waitingButtonTest']"));
      Assert.fail("Finding Native elements by css selector is not supported.");
    } catch (WebDriverException e) {
      Assert.assertTrue(e.getMessage().contains(
          "By locator ByCssSelector is curently not supported!"));
    }
  }
Child element finding test for the native view part of selendroid.

@author ddary
selendroid-test-app/src/test/java/io/selendroid/nativetests/NativeChildElementFindingTest.java