Improve less and write unit tests

[jcubic]

Expected behavior

less render text properly

Actual behavior

text is cut by number of columns

Steps to reproduce

Open less with unicode demo https://codepen.io/jcubic/pen/oMYbRG

the problem is this code, added when adding handling of images:

                    var defer = $.Deferred();
                    var parts = text.split(img_split_re).filter(Boolean);
                    var promise = defer.promise();
                    if (parts.length === 1) {
                        defer.resolve(parts);

parts is not lines it should be:

defer.resolve(text.split('\n'));

TODO:

• Fix Initial issue
• Write Base Unit Tests
• Fix onerror issue
• Unit test for images

[jcubic]

This is critical because tests for less are broken. (part of tests are disabled and it break build because I've added a check, but after removing disabled tests they fail).

[jcubic]

Bug chunk of the less plugin is slicing images, it will be challanging to test this, it will require to mock Canvas and Image.

Fore reference:

• How do you use Jest to test img.onerror
• jest-canvas-mock

TODO: if less don't load image it will break, don't load.