spring boot test junit null pointer exception - junit5

Question

im new on this of unit tests, so im trying to code the unit test for my service, right now i have this class
package com.praxis.topics.service;
import com.praxis.topics.exception.EntityNotFoundException;
import com.praxis.topics.model.Topic;
import com.praxis.topics.model.enums.Status;
import com.praxis.topics.repository.TopicRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.time.LocalDateTime;
import java.util.List;
#Service("topics")
public class TopicServiceImpl implements TopicService {
private final TopicRepository topicRepository;
#Autowired
public TopicServiceImpl(TopicRepository topicRepository) {
this.topicRepository = topicRepository;
}
#Override
public List<Topic> getTopicsByStatus(int status) {
// Check if status exists in enum
if (status < 0 || Status.values().length - 1 < status)
throw new ArrayIndexOutOfBoundsException(status);
return topicRepository.findTopicByStatus(Status.values()[status]);
}
#Override
public Topic addTopic(Topic topic) {
//topic.setCreatedAt(LocalDateTime.now());
return topicRepository.save(topic);
}
#Override
public Topic updateTopic(Topic topic) throws EntityNotFoundException {
if (topicRepository.findTopicById(topic.getId()) == null)
throw new EntityNotFoundException(String.format("Topic with id: %s was not found", topic.getId()));
return topicRepository.save(topic);
}
#Override
public Topic getTopicById(String id) {
return topicRepository.findTopicById(id);
}
#Override
public void deleteTopicById(String id) {
topicRepository.deleteTopicById(id);
}
#Override
public List<Topic> getTopicsByName(String name) {
return topicRepository.findAllByNameContains(name);
}
#Override
public Topic getTopicByName(String name) {
return topicRepository.findTopicByName(name);
}
#Override
public List<Topic>getAllTopics(){
return topicRepository.findAll();
}
}
the model of topics is this
package com.praxis.topics.model;
import com.praxis.topics.model.enums.Status;
import org.hibernate.validator.constraints.NotEmpty;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;
import org.springframework.format.annotation.DateTimeFormat;
import java.time.LocalDateTime;
#Document(collection = "Topic")
public class Topic {
#Id
private String id;
#NotEmpty(message = "The name is required")
private String name;
#NotEmpty(message = "The description is required")
private String description;
private Status status;
private String chat;
private int teachers;
private int students;
#DateTimeFormat(pattern = "dd-MM-yyyy hh:mm:ss")
private LocalDateTime createdAt;
#DateTimeFormat(pattern = "dd-MM-yyyy hh:mm:ss")
private LocalDateTime openedAt;
#DateTimeFormat(pattern = "dd-MM-yyyy hh:mm:ss")
private LocalDateTime closedAt;
public Topic() {}
public Topic(String name, String description) {
this.name = name;
this.description = description;
this.createdAt = LocalDateTime.now();
}
and im trying to do this test for but it throws me a null pointer exception, like if the service variable wasnt initialized or something
package com.praxis.topics.service;
import com.praxis.topics.model.Topic;
import com.praxis.topics.repository.TopicRepository;
import org.springframework.beans.factory.annotation.Autowired;
import static org.junit.jupiter.api.Assertions.*;
class TopicServiceImplTest {
#Autowired
TopicServiceImpl service;
#org.junit.jupiter.api.Test
void addTopic() {
Topic topic = new Topic("java", "test");
assertEquals(topic, service.addTopic(topic));
}
}
and this are the exceptions i get
java.lang.NullPointerException at com.praxis.topics.service.TopicServiceImplTest.addTopic(TopicServiceImplTest.java:29)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:436)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:115)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:170)
at org.junit.jupiter.engine.execution.ThrowableCollector.execute(ThrowableCollector.java:40)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:166)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:113)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:58)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$3(HierarchicalTestExecutor.java:112)
at org.junit.platform.engine.support.hierarchical.SingleTestExecutor.executeSafely(SingleTestExecutor.java:66)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.executeRecursively(HierarchicalTestExecutor.java:108)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.execute(HierarchicalTestExecutor.java:79)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$2(HierarchicalTestExecutor.java:120)
at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133)
at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:430)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$3(HierarchicalTestExecutor.java:120)
at org.junit.platform.engine.support.hierarchical.SingleTestExecutor.executeSafely(SingleTestExecutor.java:66)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.executeRecursively(HierarchicalTestExecutor.java:108)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.execute(HierarchicalTestExecutor.java:79)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$2(HierarchicalTestExecutor.java:120)
at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133)
at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:430)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$3(HierarchicalTestExecutor.java:120)
at org.junit.platform.engine.support.hierarchical.SingleTestExecutor.executeSafely(SingleTestExecutor.java:66)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.executeRecursively(HierarchicalTestExecutor.java:108)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.execute(HierarchicalTestExecutor.java:79)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:55)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:43)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:170)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:154)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:90)
at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:65)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
any idea? i think that its because some of the variable dont get initialized, but im doing adding the #Autowired on those so i dont know what it is
this is my pom file
http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
<groupId>com.praxis</groupId>
<artifactId>topics</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>topics</name>
<description>Project for Integrador 2018</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.10.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.restdocs</groupId>
<artifactId>spring-restdocs-mockmvc</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-jsr310</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-test</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

Answer 1

For starters, if you're using JUnit Jupiter (the programming model in JUnit 5), you'll have to configure the Jupiter Test Engine in your build.
I recommend you use the official spring-boot-sample-junit-jupiter sample project as a template.
The pom.xml shows how to configure the Jupiter Test Engine with the Maven Surefire Plugin:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<dependencies>
<dependency>
<groupId>org.junit.platform</groupId>
<artifactId>junit-platform-surefire-provider</artifactId>
<version>${junit-platform.version}</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
Note that it also shows that you need dependency declarations for
junit-jupiter-api and junit-jupiter-engine.
And SampleJunitJupiterApplicationTests shows how to configure Spring Boot's testing support with the SpringExtension for JUnit Jupiter:
#ExtendWith(SpringExtension.class)
#SpringBootTest
class TopicServiceImplTest {
#Autowired
TopicService service;
// ..
}

Answer 2

We had recently started using Spring 4.3, JUnit5, Maven together as well and got NullPointerException in integration tests where #Autowired was used.
Solution for us was to upgrade maven-related test dependencies:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-failsafe-plugin</artifactId>
<version>3.0.0-M4</version> // upgraded from 2.19.1
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>3.0.0-M4</version> // upgraded from 2.19
</plugin>

Answer 3

Your TopicServiceImplTest class is not spring component so #Autowired won't work.
Spring Boot test should be annotated with #SpringBootTest and #RunWith(SpringRunner.class). Optionaly you could use other annotations to define your context to suit your specific needs. You can find basic information here: https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-testing.html