How to assert image present in selenium python web driver?

Question

I want to assert that an image is present on a page. I'm using selenium web driver with python. I also want a message printed when the image has not been loaded. Can anyone help me with a script?

Here is a piece of html code that displays an image on a website: [img src='photo.jpg' class='image class']

Answer 1

I can't help with python, but can give a general suggestion and Java code for those who are looking to do something similar in Java. My approach would be

1. Get the src attribute of the image and make a quick HTTP GET call and make sure you get 200 OK response.
2. Once thats done, you could check the naturalWidthattribute of the WebElement using Javascript. If its more than 0, its rendered fine. However this works differently in IE. IE has .complete attribute. It will be true if the image is rendered (Reference here)

Here is sample Java code,

@Test
   public void test()
   {
      WebDriver driver = new FirefoxDriver();
      String url = "http://www.espncricinfo.com/";
      driver.get(url);
      WebElement img = driver.findElement(By.cssSelector("a[title='ESPN Cricinfo']>img"));
      String src = img.getAttribute("src");
      Client client = Client.create();
      WebResource resource = client.resource(src);
      assertThat("Response code is not 200 OK", resource.get(ClientResponse.class).getStatus(), equalTo(200));
      assertThat("Image is not rendered correctly", isImageVisible(driver, img),equalTo(true));
      driver.quit();
   }
   public boolean isImageVisible(WebDriver driver, WebElement image)
   {
      Boolean result = null;
      if (driver instanceof InternetExplorerDriver || ((RemoteWebDriver) driver).getCapabilities().getBrowserName().equals("internet explorer"))
      {
         result = (Boolean) ((JavascriptExecutor) driver).executeScript("return arguments[0].complete;", image);
      }
      else
      { //other browser types use diff method to check
         result = (Boolean) ((JavascriptExecutor) driver).executeScript("return (typeof arguments[0].naturalWidth!=\"undefined\" && arguments[0].naturalWidth>0);", image);
      }
      return result.booleanValue();
   }
}