How to run all test classes but only start embedded Tomcat once when using Spring Boot?

Question

My project has a lot of Test classes like this:

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class RefererCheckerTest {
...

Each time I want to run all test classes, everyone of them will show the log like this:

2018-08-15 14:59:31.104 [main] INFO osbcetTomcatEmbeddedServletContainer [TomcatEmbeddedServletContainer.java:201] -Tomcat started on port(s): 63003 (http)

2018-08-15 14:59:31.112 [main] INFO cbsmfilter.OAuthLoginTest [StartupInfoLogger.java:57] -Started OAuthLoginTest in 27.571 seconds (JVM running for 33.229)

It seems that initializing a Spring Boot project and its embedded Tomcat costs a lot time. If I have 100 Test classes, it will cost me 27.571 seconds *100 to run all test classes.

Could I have a way to init Spring Boot and Embedded Tomcat only once when run through all my 100 test classes? Time will be saved if so.

Answer 1

There are many scenarios that could cause the spring-context to reload and start w new server, for example:

• @DirtContext:
• @TestPropertySource
• Different @ContextConfgiurations
• Combination of @WebMvcTest / @SpringBootTest / @SpringBootConfiguration
• Different @ActiveProfiles

So, let me say what we normally use here to avoid this problems:

First, we create an abstract class that will contain all the params and configurations for the tests:

@RunWith(SpringRunner.class)
@ActiveProfiles("test") 
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@ContextConfiguration(classes = [<your application class OR context class>])
public abstract class AbstractSpringBootTest {
}

And then, in all the tests I extend this test class:

public class RefererCheckerTest extends AbstractSpringBootTest {
   ....
}

This makes the SpringBoot start only once during the tests if all of them contain the same configuration.

We current use Spring-Boot 2.0.4.RELEASE and it works perfectly.

NOTE: We use SpringRunner instead of SpringJUnit4ClassRunner as well, it is available since spring-test:4.3+ and requires JUnit 4.12+.

Also, even if the spring-boot restarts, it is supposed to reload only part of the context, and not everything again and take the same time. Also, check how are you running the tests.