code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC licenses this file
  // to you under the Apache License, Version 2.0 (the
  // "License"); you may not use this file except in compliance
  // with the License.  You may obtain a copy of the License at
  //
  //   http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing,
  // software distributed under the License is distributed on an
  // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied.  See the License for the
  // specific language governing permissions and limitations
  // under the License.
  
  package org.openqa.selenium.support.pagefactory;
  
  import static org.assertj.core.api.Assertions.assertThat;
  import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
  import static org.mockito.Mockito.atLeast;
  import static org.mockito.Mockito.mock;
  import static org.mockito.Mockito.times;
  import static org.mockito.Mockito.verify;
  import static org.mockito.Mockito.when;
  
  import java.lang.reflect.Field;
  import java.time.Clock;
  import java.time.Duration;
  import java.util.ArrayList;
  import java.util.List;
  import org.junit.jupiter.api.Tag;
  import org.junit.jupiter.api.Test;
  import org.openqa.selenium.By;
  import org.openqa.selenium.NoSuchElementException;
  import org.openqa.selenium.WebDriver;
  import org.openqa.selenium.WebElement;
  import org.openqa.selenium.support.ByIdOrName;
  import org.openqa.selenium.support.ui.TickingClock;
  
  @Tag("UnitTests")
  class AjaxElementLocatorTest {
  
    private TickingClock clock = new TickingClock();
  
    protected ElementLocator newLocator(WebDriver driver, Field field) {
      return new MonkeyedAjaxElementLocator(clock, driver, field, 10);
    }
  
    @Test
    void shouldContinueAttemptingToFindElement() throws Exception {
      Field f = Page.class.getDeclaredField("first");
      final WebDriver driver = mock(WebDriver.class);
      final By by = new ByIdOrName("first");
      final WebElement element = mock(WebElement.class);
  
      when(driver.findElement(by)).thenThrow(new NoSuchElementException("bar")).thenReturn(element);
  
      ElementLocator locator = newLocator(driver, f);
      WebElement returnedElement = locator.findElement();
  
      assertThat(returnedElement).isEqualTo(element);
    }
  
    @Test
    void shouldContinueAttemptingToFindElements() throws Exception {
      Field f = Page.class.getDeclaredField("first");
      final WebDriver driver = mock(WebDriver.class);
      final By by = new ByIdOrName("first");
      final WebElement element = mock(WebElement.class);
      final List<WebElement> elementList = new ArrayList<>();
      elementList.add(element);
  
      when(driver.findElements(by))
          .thenThrow(new NoSuchElementException("bar"))
          .thenReturn(elementList);
  
      ElementLocator locator = newLocator(driver, f);
      List<WebElement> returnedList = locator.findElements();
  
      assertThat(returnedList.get(0)).isEqualTo(element);
    }
  
    @Test
    void shouldThrowNoSuchElementExceptionIfElementTakesTooLongToAppear() throws Exception {
      Field f = Page.class.getDeclaredField("first");
      final WebDriver driver = mock(WebDriver.class);
      final By by = new ByIdOrName("first");
  
      when(driver.findElement(by)).thenThrow(new NoSuchElementException("bar"));
  
      ElementLocator locator = new MonkeyedAjaxElementLocator(clock, driver, f, 2);
  
      assertThatExceptionOfType(NoSuchElementException.class).isThrownBy(locator::findElement);
  
      // Look-ups:
      // 1. In "isLoaded"
      // 2. Immediately after call of load. (clock is 0)
      // 3. First sleep, then third call.   (clock is 1)
      // 4. Main loop is now over. Final call as we exit to see if we've loaded.
      // The last call guarantees we've called "isLoaded" at least once after a load.
      verify(driver, times(4)).findElement(by);
    }
  
    @Test
    void shouldAlwaysDoAtLeastOneAttemptAtFindingTheElement() throws Exception {
      Field f = Page.class.getDeclaredField("first");
      final WebDriver driver = mock(WebDriver.class);
      final By by = new ByIdOrName("first");
  
      when(driver.findElement(by)).thenThrow(new NoSuchElementException("bar"));
  
      ElementLocator locator = new MonkeyedAjaxElementLocator(clock, driver, f, 0);
  
      assertThatExceptionOfType(NoSuchElementException.class).isThrownBy(locator::findElement);
  
      verify(driver, atLeast(2)).findElement(by);
    }
  
    @Test
    void shouldWorkWithCustomAnnotations() {
      final WebDriver driver = mock(WebDriver.class);
  
      AbstractAnnotations npeAnnotations =
          new AbstractAnnotations() {
            @Override
            public boolean isLookupCached() {
              return false;
            }
  
            @Override
            public By buildBy() {
              throw new NullPointerException();
            }
          };
  
      assertThatExceptionOfType(NullPointerException.class)
          .isThrownBy(() -> new AjaxElementLocator(driver, 5, npeAnnotations));
    }
  
    private class MonkeyedAjaxElementLocator extends AjaxElementLocator {
  
      public MonkeyedAjaxElementLocator(
          Clock clock, WebDriver driver, Field field, int timeOutInSeconds) {
        super(clock, driver, field, timeOutInSeconds);
      }
  
      @Override
      protected long sleepFor() {
        clock.sleep(Duration.ofSeconds(1));
        return 0;
      }
    }
  
    private static class Page {
  
      @SuppressWarnings("unused")
      private WebElement first;
    }
  }
  