I'm running CasperJS with PhantomJS. I have it going to a url and clicking on an element based on XPath. This could happen several times without a problem, until, I suspect there is a delay in the page loading, it can't find the XPath, it throws an error and stops the test. I would like it to continue through the error. I don't want to wait+click any longer than I already am, as there are many clicks going on, and an error can be at a random click, waiting on every click is counter productive.
I have tried putting the whole test into a try catch, it wouldn't catch.
The only handling I could find just gave out more information on the error, still stopped the test.
I would wait for the selector you want to run, with a short timeout. In the success function do your click, in the timeout function report the problem (or do nothing at all).
For instance:
casper.waitForSelector('a.some-class', function() {
this.click('a.some-class');
}, function onTimeout(){
this.echo("No a.some-class found, skipping it.");
},
100); //Only wait 0.1s, as we expect it to already be there
});
(If you were already doing a casper.wait() just before this, then replace that with the above code, and increase the timeout accordingly.)
You cannot catch an error in something that is executed asynchronously. All then* and wait* functions are step functions which are asynchronous.
Darren Cook provides a good reliable solution. Here are two more which may work for you.
casper.options.exitOnError
CasperJS provides an option to disable exiting on error. It work reliably. The complete error with stacktrace is printed in the console, but the script execution continues. Although, this might have adverse effects when you also have other errors on which you may want to stop execution.
try-catch
Using a try-catch block works in CasperJS, but only on synchronous code. The following code shows an example where only the error message is printed without stacktrace:
casper.then(function() {
try {
this.click(selector);
} catch(e){
console.log("Caught", e);
}
});
or more integrated:
// at the beginning of the script
casper.errorClick = function(selector) {
try {
this.click(selector);
} catch(e){
console.log("Caught", e);
return false;
}
return true;
};
// in the test
casper.then(function() {
this.errorClick("someSelector");
});
Related
tl;dr: When I run my test case, steps executed seem to work, but the test bails out early on a failure to find an element that hasn't even loaded yet. It seems like the waits I have around locating certain elements are loaded/launched as soon as the test is launched, not when the lines should actually be executed in the test case. I think this is happening because the page is barely (correctly) loaded before the "search" for the element to verify the page has loaded bails out. How do I wrangle the event loop?
This is probably a promise question, which is fine, but I don't understand what's going on. How do I implement my below code to work as expected? I'm working on creating automated E2E test cases using Jasmine2 and Protractor 5.3.0 in an Angular2 web app.
describe('hardware sets', () => {
it('TC3780:My_Test', async function() {
const testLogger = new CustomLogger('TC3780');
const PROJECT_ID = '65';
// Test Setup
browser.waitForAngularEnabled(false); // due to nature of angular project, the app never leaves zones, leaving a macrotask constantly running, thus protractor's niceness with angular is not working on our web app
// Navigate via URL to planviewer page for PROJECT_ID
await planListingPage.navigateTo(PROJECT_ID); // go to listing page for particular project
await planListingPage.clickIntoFirstRowPlans(); // go to first plan on listing page
await planViewerPage.clickOnSetItem('100'); // click on item id 100 in the plan
});
});
planViewerPage.po.ts function:
clickOnSetItem(id: string) {
element(by.id(id)).click();
browser.wait(until.visibilityOf(element(by.css('app-side-bar .card .info-content'))), 30000); // verify element I want to verify is present and visible
return expect(element(by.css('app-side-bar .card .info-content')).getText).toEqual(id); //Verify values match, This line specifically is failing.
}
This is the test case so far. I need more verification, but it is mostly done. I switched to using async function and awaits instead of the typical (done) and '.then(()=>{' statement chaining because I prefer not having to do a bunch of nesting to get things to execute in the right order. I come from a java background, so this insanity of having to force things to run in the order you write them is a bit much for me sometimes. I've been pointed to information like Mozilla's on event loop, but this line just confuses me more:
whenever a function runs, it cannot be pre-empted and will run entirely before any other code
runs (and can modify data the function manipulates).
Thus, why does it seem like test case is pre-evaluated and the timer's set off before any of the pages have been clicked on/loaded? I've implemented the solution here: tell Protractor to wait for the page before executing expect pretty much verbatim and it still doesn't wait.
Bonus question: Is there a way to output the event-loop's expected event execution and timestamps? Maybe then I could understand what it's doing.
The behavior
The code in your function is running asynchronously
clickOnSetItem(id: string) {
element(by.id(id)).click().then(function(){
return browser.wait(until.visibilityOf(element(by.css('app-side-bar .card .info-content'))), 30000);
}).then(function(){
expect(element(by.css('app-side-bar .card .info-content')).getText).toEqual(id);
}).catch(function(err){
console.log('Error: ' + err);
})
}
According to wdio's documentation found here I should be allowed to handle an error using
browser.on('error', (err)=>{ console.log('do something') })
However, when I do this, nothing happens it isn't executed when the test fails, which from my understanding should have happened.
Am I doing this wrong? If so, how can I use the .on function to handle the test fails or errors my own way? I do know I can use try/catch blocks, but I would like something cleaner that is just called every time tests fail or there is an error.
Edit: as requested, added some code to show the error
browser.on('error', () => {
console.log('do something about the error')
})
it('should do something', function () {
const nonExistingElement = browser.getText('.idontexist')
assert.deepStrictEqual(nonExistingElement, 'Say something that isnt there')
})
What I would like to do is for the callback function of browser.on be executed whenever an error or failed test occur, in this case, I am trying to get the text of an element that doesn't exist, so naturally I will get the whole
element (".idontexist") still not existing after 500ms
But before that, as it happens I would also like to get the:
do something about the error
So far, the alternative to this, would be to put a try and catch block in my it block and do a browser.emit('error', 'Error'), which I would like to avoid so that I don't have to repeat it every single test.
I'm writing a script in Nightwatch that tests a specific element on a page. It's possible that the script could be testing a URL in which the element is not present on the page, in which case I want the script to end the test without any failures being logged.
I cannot seem to find a way to abort the test early without invoking a failure, however. Is there any way to have a Nightwatch test abort on a pass?
Here's a part of the code I'm working with for reference:
//End test if pagination is not present
'Pagination Present' : function (browser) {
browser
.execute(function() {
return document.querySelectorAll("ul[class='pagination']").length;
},
function(count){
if (count.value == 0) {
browser.assert.equal(count.value, 0, "There is no pagination on this page.");
browser.end();
}
})
},
Invoking browser.end(); closes the browser, but it reopens immediately after and the tests continue. Every single case fails, since the pagination does not exist on the given page. I'd like to end the test immediately after browser.assert.equal passes. Is there any way to do so?
You can use try/catch.
I had the same issue with some tests and i've got it to skip that assertion like this: you try to check something, but if you don't find the element, instead of failing the test, i just display a message in the console and exit the whole test:
'Test product\'s UPSs' : function (browser) {
try {
browser.assert.elementPresent('#someElement');
}
catch(err) {
console.log('this product has no Special features! Skipping');
process.exit();
}
}
In case you have further tests that you know they wouldn't fail and you'd like to continue with them, just leave out the process.exit() function. While it might not be the safest way to do it, at least it gets the job done.
I'm trying to access a file, that might not exist:
var localFolder = Windows.Storage.ApplicationData.current.localFolder;
localFolder.getFileAsync(stateFile).then(function (file) {
Windows.Storage.FileIO.readTextAsync(file).then(function (text) {
// do something with the text
});
}, function (err) {
// log error, load dummy data
});
if the file is not there, the "fail" method does get called, BUT it happens only AFTER my application halts with an exception "file not found". only when I press "continue" for the debugger does it continue to the "fail" method..
what am i doing wrong? should i check for existence beforehand?
You're seeing a first-chance exception. The debugger is breaking at the point of throw. If you hit the "continue" button on the debugger dialog, the app will keep running and the exception handler will run.
You can change this by using the "Debug|Exceptions" menu to turn off first chance exceptions.
I have been struggling with this same problem for two or three days and finally came to the following solution: I use getFilesAsync function to get the list of all files in a folder, and then look through this list to know if the needed file exists. After that I can call getFileAsyns without throwing. Not very pretty, but works for me. I agree that assuming that a developer can turn exceptions off is not the best advice... In my opinion this issue should be considered as a bug in RT implementation.
This question already has answers here:
How to terminate the script in JavaScript?
(25 answers)
Closed 7 years ago.
Is it possible in some way to stop or terminate JavaScript in a way that it prevents any further JavaScript-based execution from occuring, without reloading the browser?
I am thinking of a JavaScript equivalent of exit() in PHP.
Short answer:
throw new Error("Something went badly wrong!");
If you want to know more, keep reading.
Do you want to stop JavaScript's execution for developing/debugging?
The expression debugger; in your code, will halt the page execution, and then your browser's developer tools will allow you to review the state of your page at the moment it was frozen.
Do you want to stop your application arbitrarily and by design?
On error?
Instead of trying to stop everything, let your code handle the error. Read about Exceptions by googling. They are a smart way to let your code "jump" to error handling procedures without using tedious if/else blocks.
After reading about them, if you believe that interrupting the whole code is absolutely the only option, throwing an exception that is not going to be "caught" anywhere except in your application's "root" scope is the solution:
// creates a new exception type:
function FatalError(){ Error.apply(this, arguments); this.name = "FatalError"; }
FatalError.prototype = Object.create(Error.prototype);
// and then, use this to trigger the error:
throw new FatalError("Something went badly wrong!");
be sure you don't have catch() blocks that catch any exception; in this case modify them to rethrow your "FatalError" exception:
catch(exc){ if(exc instanceof FatalError) throw exc; else /* current code here */ }
When a task completes or an arbitrary event happens?
return; will terminate the current function's execution flow.
if(someEventHappened) return; // Will prevent subsequent code from being executed
alert("This alert will never be shown.");
Note: return; works only within a function.
In both cases...
...you may want to know how to stop asynchronous code as well. It's done with clearTimeout and clearInterval. Finally, to stop XHR (Ajax) requests, you can use the xhrObj.abort() method (which is available in jQuery as well).
You can make a JavaScript typo :D (thinking outside the box here)
thisFunctionDoesNotExistAndWasCreatedWithTheOnlyPurposeOfStopJavascriptExecutionOfAllTypesIncludingCatchAndAnyArbitraryWeirdScenario();
Or something like:
new new
Something like this might work:
function javascript_abort()
{
throw new Error('This is not an error. This is just to abort javascript');
}
Taken from here:
http://vikku.info/codesnippets/javascript/forcing-javascript-to-abort-stop-javascript-execution-at-any-time/
I do:
setTimeout(function() { debugger; }, 5000)
this way I have 5 seconds to interact with UI and then in stops. Las time I used was when I needed to leave custom tooltip visible, to do some styling changes.
No.
Even if you throw an exception, it will only kill the current event loop. Callbacks passed to setTimeout or DOM/XMLHttpRequest event handlers will still run when their time comes.
I am using
return false;
if I want to abort from JavaScript from running further downwards.
If you're in a function you can exit it using return; but that doesn't stop execution of the parent function that called that function.
You can call return early in a function, and at least that function will stop running. You can also just use throw '' to cause an error and stop the current process. But these won't stop everything. setTimeout and setInterval can make delayed functions and functions that run on a time interval, respectively. Those will continue to run. Javascript events will also continue to work as usual.
I know this is old, but I wanted to do this and I have found, in my opinion, a slightly improved solution of the throw answers. Just temporary supress the error messages and reactivate them later using setTimeout :
setTimeout(function() {
window.onerror = function(message, url, lineNumber) {
return false;
};
}, 50); // sets a slight delay and then restores normal error reporting
window.onerror = function(message, url, lineNumber) {
return true;
};
throw new Error('controlledError');
Define a variable inside the JavaScript function, set this variable to 1 if you want ot execute the function and set it to 0 if you want to stop it
var execute;
function do_something()
{
if (execute == 1)
{
// execute your function
}
else
{
// do nothing
}
}
The process is tedious, but in Firefox:
Open a blank tab/window to create a new environment for the script
from the current page
Populate that new environment with the script to execute
Activate the script in the new environment
Close (that is, kill) that new environment to ...
stop or terminate JavaScript this [in a] way to [that it] prevent[s] any further
JavaScript-based execution from occuring, without reloading the browser
Notes:
Step 4 only stops execution of JavaScript in that environment and not the scripts of any other windows
The original page is not reloaded but a new tab/window is loaded with the script
When a tab/window is closed, everything in that environment is gone: all remnants, partial results, code, etc.
Results must migrate back to the parent or another window for preservation
To rerun the code, the above steps must be repeated
Other browsers have and use different conventions.