Testing Spring Applications is an integral part of enterprise software development. It is a process of finding bugs in the software under development to give reliable solutions to the client. The software test process is performed by testers to improve the quality of the application by checking the result and performance of the software application for various types of inputs. The process involves steps such as defining and executing test cases, and identifying problems and fixing them. There are many types of testing; however, we will focus on the unit and integration testing in spring.
The Unit Testing
Unit testing is a basic type of testing in the development process. The smallest part of the source code consisting of modules is called a unit. For procedural language, a unit can be a program, function, and so on; however, an object-oriented language, a unit is generally represented by a class. The test performed on these units is called a unit test. The purpose of the unit test is to separate each piece of program and ensure that individual pieces of the code are correct.
While performing unit testing in the Spring framework, you do not need to set up the runtime infrastructure. If your application uses the Plain Old Java Object (POJO) concept, it can be tested in the Junit tests with objects whose instance is created by using the new operator.
Spring facilitates unit testing due to the DI feature of the Spring framework. For example, you can test the objects of the service layer by mocking the DAO interface, without accessing the persistent data while running unit tests.
The Integration Testing
The abbreviated name of integration testing is I&T. In I&T, individual modules are combined and tested as a group. I&T is normally performed after unit test. I&T takes unit tested modules as input, group them into larger units, and prepares the output for System test. Test cases are designed to test that all the modules are functioning appropriately. The different types of I&T are the big bang, backbone, top-down, and bottom-up.
The spring-mock.jar file is used for integration tests in the Spring framework. You can perform I&T to ensure the following in a Spring application:
- The correct wiring of spring contexts
- Data access using JDBC or ORM tool
For this, Spring provides various classes support bundled in the form of the spring test JAR file. In this JAR file, you find the org.springframework.test package, which contains classes such as TestContext and TestContextManager, which are used for integration.
The following functionalities are provided by the Spring integration testing:
- Context management and caching
- DI of the test fixtures
- Transaction management
- Inherited instance variables
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