Code implementation to analyze the JUnit framework

Introduction: This article describes the JUnit code implementation in detail, based on the demonstration of the code flow UML diagram, detailed analysis of JUnit's internal implementation code functions and mechanisms, and in the relevant design patterns where the combination of code to explain. In addition, the analysis process involves advanced features of the Java language such as Reflection.

Overview

As the test-driven development philosophy has become popular today, JUnit's core position in the field of test development is increasingly stable. Not only does Eclipse use JUnit as the default IDE integration component, but the various test frameworks based on JUnit are also widely used in the industry and are well received. While the introduction of JUnit book articles is more, most of them are for JUnit's specific application practices, but for JUnit's own mechanism, it stays in the shallow level of the framework module.

This article fully describes JUnit's detailed code implementation, and provides a detailed analysis of the functionality and mechanism of JUNIT's internal implementation code, based on a UML diagram of the code flow, and explains it in conjunction with code where relevant design patterns are involved. In addition, the analysis process involves advanced features of the Java language such as Reflection.

The reader of this article should be aware of JUnit's basic principles and various design patterns, mainly for the design, development and testing of Java-related technologies. For c++,c# programmers also have a good reference role.

Introduction to Junit

The concept and use of JUnit

JUnit is an open source unit testing framework written by Erich Gamma and Kent Beck. It is a white-box test, and as long as the class to be tested inherits the TestCase class, a series of JUnit mechanisms can be used to facilitate automated testing.

JUnit's design is streamlined and easy to learn, but the functionality is powerful, thanks to its built-in code structure. Erich Gamma is one of the famous GOF, so JUnit is deeply permeated with the idea of excellent design patterns. The API provided by JUnit allows you to write out the specific reusable unit test cases for test results, as well as the ability to run the unit test cases in batches. In a framework that has already been implemented, users can choose three ways to display test results, and the way they are displayed is extensible.

JUnit Fundamentals

A JUnit test contains the following elements:

Table 1. Test Case composition

Development Code Section	Test Code Section	Test Tools Section
Class A to be tested	By extending TestCase or constructing testsuit methods Write Test class B	A test run (testrunner) R, you can select a graphical interface or a text interface

Operation Steps:

Pass B through command-line or graphical interface selection to R,r to run the test automatically, and display the results.