Selenium: Handling exceptions for element that may not be present - selenium

I have a handful of pages where I want to look for an element, and if it is present, get the text. But I've run into a bit of a conundrum with respect to exception handling.
I can use WebDriverWait:
wait.until(EC.presence_of_element_located((By.XPATH, '//div[#class="className"]')))
But if this throws an exception, I technically have no way of knowing whether it occurred because the element is in fact not present on the page, or because of something else (e.g. I didn't wait long enough or there's some other error in the code).
In my particular case I've been able to deal with this so far by using the presence of some other elements on the page to infer whether the one I'm looking for will be present. However, I am bound to run into some pages where I can't use other elements as proxies.
Is there any way for me to distinguish between an exception caused by the element actually not being in the page source versus some other reason?

You should specify the Exception you want to catch and then do something in the catchblock, refer to the Java Doc here to give you more insight on exceptions
http://selenium.googlecode.com/git/docs/api/java/index.html
public void aMethod() {
try {
//do someting
} catch( Exception e ) {
textLog( "Element not present -------" );
detailedText( e );
}
}

Related

E2E testing multiple posibilities with exception

i have a problem that i don't exactly know how to solve. I'm implementing an E2E test in which using selenium i need to click in a Link and check that is sending me to the right URL.
Here starts the problem...
There are 3 possibilities, mix of 2 types of links, just one type of link or the other type of link. No problems with the situations in which there are both types of links but when there is just one type when it searches for the identifier we use for the links that are not in page it gives me a timeoutException. This is not a failure because it's a posible situation but i will like to know if there is a way in which to check that if it finds no links it asserts that the exception is thrown.
I though using a runCatching (or try catch) wait for the link to appear and if it doesn't appear the test asserts that when i look for the element the timeout exception is thrown again.
It smells a bit for me this way of doing it and i don't know if it's correctly done.
EDIT: Im ussing AssertK and JUnit5 for testing.
EDIT 2: I've done this, i dont know if it a correct way of doing it
runCatching {
driver.waitFor(numberOfWidgetsToBeMoreThan(BrowserSelector.cssSelector(OFFERS_WITH_PRICE_AND_DATE), 0), ofMillis(2000))
}.onFailure {
assertThrows<WaitTimeoutException> {
findLink(OFFERS_WITH_PRICE_AND_DATE)
}
}.onSuccess {
val widget = findLink(OFFERS_WITH_PRICE_AND_DATE)
widget.click()
assertThat(driver.url).contains(NO_DATE_TEXT)
}
I'm not sure I understood your problem correctly, but you can use assertFails to assert that a piece of code throws an exception:
#Test
fun test() {
val exception = assertFails {
// some code that should throw
}
// some more assertions on the type of exception etc. may go here
}

Logback/SLF4J - is there a configuration setting to prevent a stack trace being printed out?

In my app code I have a situation where I want an Exception to be fully printed out with the stack trace and everything.
In my testing code for this situation, when I deliberately doThrow(), to test the handling of this Exception, I want still to log to error, but without the stack trace, partly to prevent cluttering the log, partly to prevent the testing code wasting time printing a stack trace I have no need of.
Is there a way I can do this in my logback-test.xml?
Well, I did find a workaround... but it's not for TDD purists.
In my app class under test (it could actually be some utility class and then be used by any app class) I put this:
private boolean printErrorStackTrace = true;
void setPrintErrorStackTrace( boolean doPrint ){
printErrorStackTrace = doPrint;
}
Again in the app class I changed the LOGGER line from this
LOGGER.error(String.format("file was %s", documentFile), e);
to this:
LOGGER.error(String.format("file was %s", documentFile),
printErrorStackTrace? e : null );
And then in my test method I put this:
appClass.setPrintErrorStackTrace( false );
... obviously we're told not to allow testing code to reach into app code ... but of course I could instead have use a method getPrintErrorStackTrace() in the condition clause... and then mocked that method in the testing code. But would that have been any less heretical? We're also told not to add functionality just to help testing.
But my log now looks a lot cleaner...

Condition- assert using Selenium

I want to write a script which can detect this message " System is not responding to your request. Kindly try after sometime." as shown in the screenshot below. When this message comes up then I want verify and send mail to the development team.
Snippet which I wrote for verification purpose but it is not working fine for me, pls suggest some alternative:
String s1 = d1.findElementByXPath(".//*[#id='showSearchResultDiv']").getText();
System.out.println(s1);
Remember to be careful when writing code for automation. If the scenario doesn't always show up, you cannot try and find an XPath, because you can't getText() if the object (based on the XPath) doesn't exist first. You probably need a try/catch around your code, and then put the println inside the try. This scenario will occur quite frequently, so you may want to write your own framework on top of WebDriver to handle these use cases.
If that is not the issue. Put a try/catch around the code that is failing to capture what the exception is.
You should try to wait for your element to appear before examining its text:
for (int second = 0;; second++) {
if (second >= 60) fail("timeout");
try { if (d1.findElementByXPath(".//*[#id='showSearchResultDiv']").isDisplayed()) break; } catch (Exception e) {}
Thread.sleep(1000);
}
String s1 = d1.findElementByXPath(".//*[#id='showSearchResultDiv']").getText();
System.out.println(s1);
The exact code may be different, depending on the webpage you're testing (e.g. you should remove the 'fail' line if it's OK for the element not to appear every time.

PHP Error handling: die() Vs trigger_error() Vs throw Exception

In regards to Error handling in PHP -- As far I know there are 3 styles:
die()or exit() style:
$con = mysql_connect("localhost","root","password");
if (!$con) {
die('Could not connect: ' . mysql_error());
}
throw Exception style:
if (!function_exists('curl_init')) {
throw new Exception('need the CURL PHP extension.
Recomplie PHP with curl');
}
trigger_error() style:
if(!is_array($config) && isset($config)) {
trigger_error('Error: config is not an array or is not set', E_USER_ERROR);
}
Now, in the PHP manual all three methods are used.
What I want to know is which style should I prefer & why?
Are these 3 drop in replacements of each other & therefore can be used interchangeably?
Slightly OT: Is it just me or everyone thinks PHP error handling options are just too many to the extent it confuses php developers?
The first one should never be used in production code, since it's transporting information irrelevant to end-users (a user can't do anything about "Cannot connect to database").
You throw Exceptions if you know that at a certain critical code point, your application can fail and you want your code to recover across multiple call-levels.
trigger_error() lets you fine-grain error reporting (by using different levels of error messages) and you can hide those errors from end-users (using set_error_handler()) but still have them be displayed to you during testing.
Also trigger_error() can produce non-fatal messages important during development that can be suppressed in production code using a custom error handler. You can produce fatal errors, too (E_USER_ERROR) but those aren't recoverable. If you trigger one of those, program execution stops at that point. This is why, for fatal errors, Exceptions should be used. This way, you'll have more control over your program's flow:
// Example (pseudo-code for db queries):
$db->query('START TRANSACTION');
try {
while ($row = gather_data()) {
$db->query('INSERT INTO `table` (`foo`,`bar`) VALUES(?,?)', ...);
}
$db->query('COMMIT');
} catch(Exception $e) {
$db->query('ROLLBACK');
}
Here, if gather_data() just plain croaked (using E_USER_ERROR or die()) there's a chance, previous INSERT statements would have made it into your database, even if not desired and you'd have no control over what's to happen next.
I usually use the first way for simple debugging in development code. It is not recommended for production. The best way is to throw an exception, which you can catch in other parts of the program and do some error handling on.
The three styles are not drop-in replacements for each other. The first one is not an error at all, but just a way to stop the script and output some debugging info for you to manually parse. The second one is not an error per se, but will be converted into an error if you don't catch it. The last one is triggering a real error in the PHP engine which will be handled according to the configuration of your PHP environment (in some cases shown to the user, in other cases just logged to a file or not saved at all).

Handling NHibernate Exceptions

What's the best practice for handling exceptions in NHibernate?
I've got a SubjectRepository with the following:
public void Add(Subject subject)
{
using (ISession session = HibernateUtil.CurrentSession)
using (ITransaction transaction = session.BeginTransaction())
{
session.Save(subject);
transaction.Commit();
}
}
And a Unit Test as follows:
[Test]
public void TestSaveDuplicate()
{
var subject = new Subject
{
Code = "En",
Name = "English"
};
_subjectRepository.Add(subject);
var duplicateSubject = new Subject
{
Code = "En",
Name = "English1"
};
_subjectRepository.Add(duplicateSubject);
}
I got to the point of handling the error generated by the unit test and got a bit stuck. This fails as expected, though with a GenericADOException, I was expecting a ConstraintViolationException or something similar (there is a uniqueness constraint on the subject code at database level).
The ADOException wraps a MySQL Exception that has a sensible error message but I don't want to start breaking encapsulation by just throwing the inner exception. Particularly as MySQL isn't finalised as the back end for this project.
Ideally I'd like to be able to catch the exception and return a sensible error to the user at this point. Are there any documented best practice approaches to handling NHibernate Exceptions and reporting back up to the user what went wrong and why?
Thanks,
Matt
I would handle it in the Add method as such:
public void Add(Subject subject)
{
using (ISession session = HibernateUtil.CurrentSession)
using (ITransaction transaction = session.BeginTransaction())
{
try
{
session.Save(subject);
transaction.Commit();
}
catch (Exception ex)
{
transaction.Rollback();
// log exception
throw;
}
}
}
In the catch block, you should first rollback the transaction and log the exception. Then your options are:
Rethrow the same exception, which is what my version does
Wrap it in your own exception and throw that
Swallow the exception by doing nothing, which is very rarely a good idea
You don't have any real options for handling the exception in this method. Assuming that the UI calls this method, it should call it in its own try..catch and handle it by displaying a meaningful error message to the user. You can make your unit test pass by using the ExpectedException(type) attribute.
To answer your question directly, you should create your own "sensible error" by extending Exception and throw that with the original exception as its InnerException. That's the exception wrapping technique I listed in (2).
All the Nhibernate exceptions are non recoverable, you could revisit the design of the app/data layer if you are trying to recover from nhibernate exceptions .
You can also Take a look at spring.net 's exception translation implementaion
Also you manually handling transactions on exceptions is tedious and error prone, take a look at nhibernate's contextual sessions .
Spring.net also has some nice helpers around nhibernate .
The general question is going to be, what do you want to tell the user, and who is the user?
If the user will sometimes be another computer (i.e., this is a web service), then you would want to use the appropriate mechanism to return a SOAP Fault or HTTP error.
If the user will sometimes be a UI of some sort, then you may want to display a message to the user, but what would you tell the user so he can do something about it? For instance, most web sites will say, "sorry, we had an unexpected error", no matter what the reason. That's because there's usually nothing the user could do about the error.
But in either case, the choice of how to tell "the user" is a matter for the Presentation layer (UI tier), not for the DAL. You should possibly wrap exceptions from the DAL in another exception type, but only if you're going to change the message. You don't need your own exception class, unless your callers would do something different if it's a data access exception rather than some other kind.
I'd probably validate the input before saving the object; that way you can implement whatever validation you like (e.g. check the length of the Subject Code as well as the fact that there aren't any duplicates), and pass back meaningful validation errors back to the user.
The logic is as follows; exceptions are used to indicate exceptional circumstances that your program doesn't cater for. A user entering a duplicate Subject Code in your example above is something your program should be catering for; so, rather than handling an exception because a DB constraint gets violated (which is an exceptional event and shouldn't be occurring), you'd want to handle that scenario first and only attempt to save the data when you know that the data you're saving is correct.
The advantage with implementing all validation rules in your DAL is that you can then ensure that the data going into your DB is valid as per your business processes in a consistent manner, rather than relying on the constraints in your DB to catch those for you.