如何使用Mockito模拟WebDriver？

Question

I want to be able to do unit test for my Selenium integration tests and to do that I need to be able to mock the driver and the elements needed for the tests, this is a quick example of a function that returns the name of the element.

public class demo {

  private WebDriver mockDriver;
  private WebElement mockElement;

  @Before
  public void setUp(){
    this.mockDriver = mock(WebDriver.class);
    this.mockElement = mock(WebElement.class, withSettings().name("elementName"));
    when(this.mockDriver.findElement(By.id("testmock"))).thenReturn(mockElement);
  }

  public String getName(String id){
    WebElement testElement = mockDriver.findElement(By.id(id));
    return testElement.getAttribute("name");
  }

  @Test
  public void assertElementName() throws InterruptedException {
    Assert.assertTrue(getName("testmock").equals("elementName"));
  }
}

this gives me a java.lang.NullPointerException on the return in getName() . I am obviously using this wrong but I can't figure out how. Anyone with some experience in this that could point me in the right direction?

Answer 1

You are misunderstanding what this piece of code does:

this.mockElement = mock(WebElement.class, withSettings().name("elementName"));

The withSettings() clause gives the mock object a name, meaning that certain error messages produced by Mockito will use this name. You are not setting any properties on the WebElement object.

So... when your code reaches this part:

return testElement.getAttribute("name");

It returns null because there is no attribute with that value. If you wanted to have an attribute, then you'd need to add something like the following:

when(this.mockElement.getAttribute("name")).thenReturn("elementName");