Spring Boot – How to init a Bean for testing?
In Spring Boot, we can create a @TestConfiguration class to initialize some beans for testing class only.
P.S Tested with Spring Boot 2
1. @TestConfiguration + @Import
This @TestConfiguration class will not pick up by the component scanning, we need to import it manually.
TestConfig.java
package com.mkyong;
import org.springframework.boot.test.context.TestConfiguration;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.context.annotation.Bean;
import java.time.Duration;
@TestConfiguration
public class TestConfig {
@Bean
public RestTemplateBuilder restTemplateBuilder() {
return new RestTemplateBuilder()
.basicAuthentication("mkyong", "password")
.setConnectTimeout(Duration.ofSeconds(5));
}
}
RestTemplateTest.java
package com.mkyong;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.web.client.TestRestTemplate;
import org.springframework.context.annotation.Import;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@SpringBootTest
@Import(TestConfig.class)
public class RestTemplateTest {
@Autowired
private TestRestTemplate restTemplate;
@Test
public void post_user_ok() {
//...
}
}
2. @TestConfiguration + Inner Static Class
Alternatively, create a inner class like this :
RestTemplateTest.java
package com.mkyong;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.TestConfiguration;
import org.springframework.boot.test.web.client.TestRestTemplate;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.test.context.junit4.SpringRunner;
import java.time.Duration;
@RunWith(SpringRunner.class)
@SpringBootTest
public class RestTemplateTest {
@TestConfiguration
static class TestConfig {
@Bean
public RestTemplateBuilder restTemplateBuilder() {
return new RestTemplateBuilder()
.basicAuthentication("mkyong", "password")
.setConnectTimeout(Duration.ofSeconds(5));
}
}
@Autowired
private TestRestTemplate restTemplate;
@Test
public void post_user_ok() {
//...
}
}
References
About Author
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“In Spring Boot, we can create a @TestConfiguration class to initialize some beans for testing class only. ” – not exactly truth. This will initialize all application beans plus those declared in @TestConfiguration configuration.
How can we only inject a specific bean in a JUnit test?
Hi,
I am trying to Autowire a non manned spring class – below –
@TestConfiguration public class EasyRandomConfiguration { @Primary @Bean public EasyRandom easyRandom(){ EasyRandomParameters parameters = new EasyRandomParameters() .seed(123L) .objectPoolSize(20) .randomizationDepth(5) .charset(Charset.forName("UTF-8")) .timeRange(LocalTime.now().minusHours(24), LocalTime.now()) .dateRange(LocalDate.now().minusYears(20), LocalDate.now()) .stringLengthRange(5, 10) .collectionSizeRange(1, 5) .scanClasspathForConcreteTypes(true) .overrideDefaultInitialization(false) .ignoreRandomizationErrors(true); return new EasyRandom(parameters); } }And trying to Autowire in –
@DataMongoTest @RunWith(SpringRunner.class) @Import(EasyRandomConfiguration.class) @ActiveProfiles("test") public class PersonRepositoryTest { @Autowired private PersonRepository personRepository; @Autowired private EasyRandom easyRandom;but getting following error – Any Suggesion
java.lang.NullPointerException
at com.kuberaya.core.test.repository.PersonRepositoryTest.<init>(PersonRepositoryTest.java:38)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
at org.junit.runners.BlockJUnit4ClassRunner.createTest(BlockJUnit4ClassRunner.java:250)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:226)
Great Articles from MKyong. Its really helpful. Much appreciated.