When comparing tape vs CasperJS, the Slant community recommends CasperJS for most people. In the question“What are the best JavaScript unit testing tools?” CasperJS is ranked 3rd while tape is ranked 5th. The most important reason people chose CasperJS is:
There are times where you don't want to open up a browser for screencaps, that is where CasperJS comes to use, it can render the page using its own rendering engine and take and save a screenshot for you, all via the commandline
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Pros
Pro Simple API
Very simple API that doesn't require globals, or monkey patching objects for assertions.
Pro Built-in assert
This way you don't have to add more dependencies and external assertion libraries.
Pro No global functions
Tape does not use global methods such as "it", "describe", since they are not considered best practice in JavaScript.
Pro It follows the principles of TAP
TAP: Test Anything Protocol
Pro Allows screenshots (either the full page or parts of it) if performing UI testing
There are times where you don't want to open up a browser for screencaps, that is where CasperJS comes to use, it can render the page using its own rendering engine and take and save a screenshot for you, all via the commandline
Pro Easy to understand
Pro Written in JavaScript
Since all webdevs know JS, the start-up time of learning the framework will be reduced to zero, as your team can be productive from day one.
Pro Easily integrates with other applications
Due to the simplicity of the framework, not only other libraries can be built with it, but it can be integrated with any web application as well.
Pro Can run javascript code inside pages being tested
Can execute arbitrary javascript or load external JS into the page being tested. This feature is possible due to the presence of a rendering engine, and helps you see the effects of any client side scripting during your tests.
Cons
Con No concurrency
Cannot run async test cases concurrently for faster test builds.
Con Not for unit testing but rather UI testing
These are two extremely different concepts. CasperJS should be removed from this list
Con Cannot guarantee 100% accurate Webkit-based browser screenshots
QtWebKit is the rendering engine used by CasperJS. Keep in mind this is NOT the same rendering engine as Chrome; hence, if you want to be 100% sure of the results, you must run a Webkit browser (such as Chrome) yourself.