lesson10.md

Lesson 10: Unit Testing for XML Context

Overview

The @ContextConfiguration annotation is used to load Java as well as XML context.

The appContext.xml file in src/main/resources is created for the MovieRecommenderSystemApplication class.

In this file, we mention the package for component scanning using the <context:component-scan> tag. We have also defined three beans: filter, filter2, and recommenderImpl.

Demonstrated Concepts

@ContextConfiguration with locations

When using Java context, the @ContextConfiguration annotation takes classes as an argument.

To load the XML configuration, we provide locations as an argument. Since the config file is in the class path, the location can be given as follows:

@ContextConfiguration(locations="/appContext.xml")

The rest of the test will remain the same as shown in the previous lesson.

Creating a test configuration

Since we are reading the application context from a file, we can create a separate context for the purpose of testing. All test contexts should be placed in src/test/resources.

A test context is useful if we want to override something defined in the context, for the purpose of testing.

An XML file testContext.xml in src/test/resources is our test context. We can define a test context here or import the context from another file and then over-ride it.

<import resource="classpath:appContext.xml"/>

After importing the context, the beans can be defined for the purpose of testing and any bean from the original context can be over-ridden.

To use the test configuration defined above, we use testContext.xml as an argument to the @ContextConfiguration annotation.

@ExtendWith(SpringExtension.class)
@ContextConfiguration(locations="/testContext.xml")
class RecommenderImplementationXmlConfigTest {
    //...
}

In this way, we can define a separate configuration for the unit test.