Automatically generate test modules using JUnit4 and JUnitGenerator V2.0 in IDEA

Because of the needs of the project, I studied the automatic generation of test code.It will always be useful to record the experience.I personally think that it is better to have a good memory than to take more notes and more reflections and summaries.

1. Prerequisites

• Development environment is properly configured
• Project has resolved JUnit dependencies (pom.xml)
• I'm using version 4.12:

   junitjunit4.12

2. JUnit configuration in IDEA

Open the Settings window and search for junit, as shown in the figure (both plugins are checked to add):

The JUnitGenerator V2.0 plugin can help us generate test code automatically.If the search junit does not have JUnitGenerator V2.0, operate as shown below (download and add):

Calling a template's method (Alt+Insert) tests all methods by default.If you want dynamic personalized generation, you can use the shortcut operation Ctrl + Shift + T on the class page to be tested, as shown in the following figure to personalize the settings:

It is now possible to run '***test class name**' on this class via the right-click menu, or via Run → Edit Configurations.

3. JUnit common assertions and annotations

JUnit provides us with some helper functions that help us determine whether the method under test is working as expected. Usually, these helper functions are called assertions.

Assertion core method

Notes

The execution order of a test class unit test is:

 @BeforeClass –> @Before –> @Test –> @After –> @AfterClass

The calling sequence of each test method is:

 @Before –> @Test –> @After

Code example:

public class JunitFlowTest {/* **1. The method modified by @BeforeClass will be executed before all methods are called,* and the method is static, so it will run when the test class is loaded,* And it will only have one instance in memory, which is more suitable for loading configuration files.* 2. The method modified by @AfterClass is usually used to clean up resources, such as closing the connection to the database* 3. @Before and @After will be executed once before and after each test method.* */@BeforeClasspublic static void setUpBeforeClass() throws Exception {System.out.println("this is beforeClass...");}@AfterClasspublic static void tearDownAfterClass() throws Exception {System.out.println("this is afterClass...");}@Beforepublic void setUp() throws Exception {System.out.println("this is before...");}/*** Even if an exception is thrown in the @Before annotated method and @Test annotated method,* All @After annotated methods will still be executed*/@Afterpublic void tearDown() throws Exception {System.out.println("this is after");}/* *** 1. Failure is generally caused by the failure of the assertion method used in unit testing,* This indicates that the test point found a problem* , which means that the output of the program is not what we expected.* 2. Errors are caused by code exceptions, which can arise from errors in the test code itself,* can also be in the code under test* a hidden bug* 3. Test cases are not used to prove that you are right, but to prove that you are not wrong.*/@Testpublic void testAdd() {assertEquals(5, new Calculate().add(3,3));}@Testpublic void testDivide() {assertEquals(3, new Calculate().divide(6, 0));}}