Testing is critical to creating robust applications, and yet testing is very often avoided, or overlooked by developers. I believe part of the reasoning is that companies prioritize application feature speed to market over quality and robust application development. Another reason is that proper automated testing is considered difficult, whereas manual testing of an application is seen as the easier solution.

Within this chapter, we will tackle the problems and solutions of testing applications within Go and more specifically, how we can test our Echo web applications. We start by covering the five primary categories of application testing and then progress into how each type of testing can be accomplished for our example web application. It will be shown how handler and middleware functions can be tested independently of the entire system. You will learn how to mock function calls in order to test various branches of your handlers, as well as point out tools that can help. Finally, we will show how you can perform external and integration testing using Go to build instrumented executable builds.

The entire purpose of testing applications is to prove the code is performing and functioning the way it was designed. Without tests, you will have absolutely no idea what your code is actually doing. Testing is the empirical mechanism by which you can show the business the code functions and provide empirical proof to the business that this application is ready.

This chapter will showcase how to perform various testing of your Go web application. By using the standard library testing facilities for your Go application, you are provided with a framework in which you can create unit tests as well as benchmark tests for your application. By performing some build trickery, you will be shown how to compile a coverage-enabled instrumented executable, for which you can get real solid coverage numbers from your integration testing. You will learn how to unit and benchmark test your handler code, as well as middleware code to find functional and performance problems within your code. By the end of this chapter, you will have a very strong grasp on the importance and functionality of testing your Echo project.