Unit Testing JavaScript with Gulp and Mocha

Immediately after getting my first node project up and running, I started to ask how do I write and test my code?  My corporate experience has taught me the importance of automated testing, how to create them in C# with visual studio and how to automate the testing with TFS, but node and VS Code is totally different.  Visual Studio is an IDE and it will take care of almost everything for you.  You simply need to create a new project (a ‘test’ project) in you code and you are good to start writing tests.  Executing your test is as easy as a file menu click or a key board short cut.  You don’t have to think about the testing framework, how your code is built or executed because the IDE will take care of that for you.
Testing Framework
First question to answer was what does it take to write a unit test with JavaScript?  After asking around on Google I discovered node packages, mocha and should.  These libraries allow you to write simple and human readable tests.  In JavaScript, you don’t get classes per say, you need to think in terms of functions and prototypes.  In MS Test you typically create a test class that maps to one class in your code, the target class.  This thinking needs to evolve with JavaScript into files and functions.  One test file is used to test one file of code and you use functions, not classes, to define your tests.  With mocha there are two very interesting functions you need to know about, ‘describe’ and ‘it’.  When you see ‘describe’ think test class in MS Test.  Describe creates a container and label for your tests.  Now ‘it’ is the actual test, think a test method in MS Test.  The ‘it’ function needs a name and a function to execute.  The should package is what will help you make your tests more readable.  This package is similar to the NuGet package, Fluent Assertions.  It allows you replace robotic assert statements with more fluent and readable asserts.  In my experience of training interns, this fluent syntax goes a long way to help new people understand unit testing and understand what is actually going on in the tests.1
Testing Framework
First question to answer was what does it take to write a unit test with JavaScript?  After asking around on Google I discovered node packages, mocha and should.  These libraries allow you to write simple and human readable tests.  In JavaScript, you don’t get classes per say, you need to think in terms of functions and prototypes.  In MS Test you typically create a test class that maps to one class in your code, the target class.  This thinking needs to evolve with JavaScript into files and functions.  One test file is used to test one file of code and you use functions, not classes, to define your tests.  With mocha there are two very interesting functions you need to know about, ‘describe’ and ‘it’.  When you see ‘describe’ think test class in MS Test.  Describe creates a container and label for your tests.  Now ‘it’ is the actual test, think a test method in MS Test.  The ‘it’ function needs a name and a function to execute.  The should package is what will help you make your tests more readable.  This package is similar to the NuGet package, Fluent Assertions.  It allows you replace robotic assert statements with more fluent and readable asserts.  In my experience of training interns, this fluent syntax goes a long way to help new people understand unit testing and understand what is actually going on in the tests.
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Once you have these in place you can run your tests with the test command in the command pallet or the keyboard shortcut.
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Getting Started with Node

Recently I attended Microsoft’s Build conference in San Francisco.  Prior to the conference I had heard about Visual Studio Code and had starting fiddling around with it and MVC Core on Linux.  While I was there I had the opportunity to explore a few sessions and labs related to VS Code and Node.js.  Over my career I have learned many techniques for building quality into software products (such as: code reviews, unit testing, automated builds, etc.) and I have also accepted that when it comes to the user interface (i.e. JavaScript in my world) those practices either do not apply or are too time consuming to be worth pursuing.  As a result, I have formed a basised opinion and do not see any reason why a sane developer would ever choose to use JavaScript as a server side programming language.   And yet, they are and, Microsoft is promoted it.  What?  Why?  I have realized that I am missing something.  This blog series is documentation of how I’m exploring what I’m failing to understand, at the moment.
This first post will be very short because Microsoft has already done a good job of writing it 🙂  The first step in learning any new tool/framework/language is simply saying “hello” or more specifically, “hello world.”  Microsoft has provided an excellent tutorial for getting up and running with Node.

 

npm install -g express-generator
express ExpressApp
cd ExpressApp
npm install
You are then free to write in a hello world message…
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you can then fire up the debugger and point a browser to http://localhost:3000 to see the hello world
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From here I added in boot strap into the views and put together a nice starting point to branch out into future learnings.  You can see what I have done on my GitHub.