Devops for Growth

Analyzing code complexity is rather easy these days with the project like JSComplexity. Even better, the complexity metrics can be visualized in a good-looking and interactive report showing different metrics from McCabes cyclomatic complexity to Halstead complexity measures. Both these tools are easy to setup, they run quite well on the command-line (using Node.js).

Now that code coverage is tracker, perhaps you are ready for the next level? It is about setting the hard threshold so that future coverage regression will never happen. Protect yourself and your team from carelessness, overconfidence, or honest mistakes!

Testing JavaScript code is not just a matter of using some test runner and writing a few tests; it usually requires some heavy structural changes when applied to code that has been tested only manually before. We’ve walked through an example of how to change the code structure of an existing module to run some tests using an ad-hoc testing framework, then replacing that with a more full-featured framework to get useful visual results.

QUnit itself has a lot more to offer, with specific support for testing asynchronous code such as timeouts, AJAX and events. Its visual test runner helps to debug code by making it easy to rerun specific tests and by providing stack traces for failed assertions and caught exceptions. For further reading, check out the QUnit Cookbook.

Originally published on Smashing Magazine, June 2012

Istanbul is pure JavaScript, there is no native code or other kind of native libraries wrapper involved.

Istanbul requires Node.js, the package can be installed as:

Using Istanbul with command-line Node.js application is fairly straightforward. Assuming you have test.js like this:

We can analyze the coverage by running:

which gives the following outcome:

Even if you put all the above code in just one line, Istanbul can still give the correct coverage result. This is because Istanbul does not work based on line-by-line coverage, it does fully understands JavaScript syntax. Beside the quick text-based report, Istanbul also produces the coverage report in LCOV format. This way, the coverage report can be nicely shown, with color coding and other fancy features:

Nous allons voir dans cet article la logique des tests unitaires en javascript pur afin de mieux appréhender le fonctionnement des frameworks de tests automatisés tel que Jasmine, mocha ou QUnit. Nous montrerons d’ailleurs une version de ces tests avecQUnit afin de commencer à voir les possibilités que peuvent nous offrir ces frameworks.

There are many measures of code complexity, the popular ones are McCabes cyclomatic complexity and Halsteads complexity. For JavaScript applications, there is a new tool from Phil Booth called JSComplexity which can be used to analyze your code and find out the complexity measures. Besides the above two code metrics, JSComplexity also produces the logical line of code (LOC) and the overall maintainability index. There is a whole page dedicated to explain the definition of these metrics and how they are computed.

Plato is very easy to use. Just install the plato package(you need Node.js) and you are ready to analyze your own code.

Who says code analysis can’t be fun?

Fortunately, these days you can use a microlibrary called Escope (GitHub: Constellation/escope) which can analyze the scope of the entire code.

This adds another useful library to the existing family of Esprima (for parsing), Estraverse (syntax traversal tool), and Escodegen (code regeneration). This arsenal of tools can be quite deadly.