I'm trying to validate image URLs with Qunit by setting the URL as the src attribute of a test image and checking with the error event handler whether that went well. So far what I have is:

test('image',function() {
    var test_image = $('#test-image');
    test_image.error(function(e) { // properly triggered
        console.log(e);             
        is_valid = false;
        // ok(false,'Issue loading image'); breaks qunit
    });
    var is_valid = true;
    test_image.attr('src','doesntexist');
    console.log('checking is_valid');  // occurs before error event handler
    if (is_valid) {  // therefore always evaluates to the same
        ok(true,'Image properly loaded');
    } else {
        ok(false,'Issue loading image');
    }
});

My problem is that although the error event is properly triggered, it seems to occur in an asynchronous fashion and after the evaluation of is_valid (therefore whatever check I make, the result will always be the same). I have tried adding the ok() assertion inside the error event handler, but I'm getting the following error:

Error: ok() assertion outside test context

How can I run an assertion based on the processing performed inside the error event handler?

PS: if I insert a alert('test'); before checking is_valid it works fine (which confirms problem with error handler being asynchronous) but as you can imagine is not acceptable. I tried using setTimeout to delay execution of if statement but it brings the same assertion context error.

I'm trying to validate image URLs with Qunit by setting the URL as the src attribute of a test image and checking with the error event handler whether that went well. So far what I have is:

test('image',function() {
    var test_image = $('#test-image');
    test_image.error(function(e) { // properly triggered
        console.log(e);             
        is_valid = false;
        // ok(false,'Issue loading image'); breaks qunit
    });
    var is_valid = true;
    test_image.attr('src','doesntexist');
    console.log('checking is_valid');  // occurs before error event handler
    if (is_valid) {  // therefore always evaluates to the same
        ok(true,'Image properly loaded');
    } else {
        ok(false,'Issue loading image');
    }
});

My problem is that although the error event is properly triggered, it seems to occur in an asynchronous fashion and after the evaluation of is_valid (therefore whatever check I make, the result will always be the same). I have tried adding the ok() assertion inside the error event handler, but I'm getting the following error:

Error: ok() assertion outside test context

How can I run an assertion based on the processing performed inside the error event handler?

PS: if I insert a alert('test'); before checking is_valid it works fine (which confirms problem with error handler being asynchronous) but as you can imagine is not acceptable. I tried using setTimeout to delay execution of if statement but it brings the same assertion context error.

• javascript
• jquery
• image
• qunit

Share Improve this question Follow edited Aug 2, 2012 at 11:30 Max asked Aug 2, 2012 at 11:20 MaxMax 13.3k3232 gold badges9393 silver badges146146 bronze badges

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1 Answer 1

Sorted by: Reset to default 8

By quickly looking through QUnit API, I see that you should use asyncTest function for this. Before setting the src-attribute for your test_image, hook a function to load event. Here's an untested code:

asyncTest('image',function() {
    var test_image = $('#test-image');
    test_image.error(function(e) {
        console.log(e);             
        ok(false,'Issue loading image');
        start();
    });
    test_image.load(function() {
        ok(true,'Image properly loaded');
        start();
    });
    test_image.attr('src','doesntexist');
});