What is unit testing?
A unit is the smallest part of a piece of software you can actually test (for example, an individual function or procedure). Unit testing is an essential step of the software testing process. Its goal is to test individual units or components of source code and validate whether each of them performs as expected.
Why is unit testing important?
Unit testing makes it possible to identify problems earlier on, which reduces the cost of fixing them. It also makes development faster, codes more reliable, and integration of modules easier. As a result, it reduces the number of bugs and makes the whole process less time-consuming.
Although there are some challenges to unit testing, such as needing to test doubles and finding dependencies, in the long run, tackling unit testing is definitely worthwhile.
Jasmine vs. Mocha
Some of the differences between these two are that Jasmine has a built-in assertion library and a spy framework, while Mocha does not. An upside for Mocha, however, is that it excels at BDD test definitions.
Jest and Enzyme
You can use Jest individually, given that Enzyme just adds functionality, although we believe these tools are complementary and usually use them together. Enzyme, however, cannot be used on its own as it is not a unit testing framework. It will always need a test runner to function, which does not necessarily have to be Jest.
If you’d like more information on Jest and Enzyme and how to use them to run unit testing for React web apps, check out our previous article on this topic.