@ContextConfiguration defaults

Spring @ContextConfiguration is a way to specify the Application Context for a test.

The location of a xml based test application context can be specified using the locations attribute:

@ContextConfiguration(locations={"test-context.xml"})

and if @Configuration is used as the context, then a classes attibute can be specified:

@ContextConfiguration(classes={TestConfiguration.class})

There are intelligent defaults for these attributes though and that is what I wanted to highlight in this post.

If the locations or the classes attribute is not specified, the default behavior is to first look for a xml configuration with a name as the test class name - "context.xml" file

For eg. if I have a Test class this way:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
public class TestSpringCache {

The location of the configuration that will be tried first is "TestSpringCache-context.xml"

If a context is not found at this location, then a @Configuration default is looked for by scanning all static inner classes annotated with @Configuration of the test class. So if I had the following:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
public class TestSpringCache {
   ...
 
 @Configuration
 @EnableCaching
 @ComponentScan("org.bk.samples.cache")
 public static class TestConfiguration{
 .. 

the inner class TestConfiguration would be used as the source of the Application context.

The default behaviour can be changed by supplying a loader attribute to the @ContextConfiguration, say for eg, if I want to default to @Configuration with its defaults, it can done this way:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(loader=AnnotationConfigContextLoader.class)
public class TestSpringCache {
..

So to conclude, the defaults provided by @Configuration are a great way to make the tests a little more concise!