인프런 커뮤니티 질문&답변

package com.example.spring.repository;

import com.example.spring.domain.Member;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Test;

import java.util.List;

import static org.assertj.core.api.Assertions.assertThat;

class MemoryMemberRepositoryTest {

MemoryMemberRepository repository = new MemoryMemberRepository();

@AfterEach
public void afterEach() {
repository.clearStore();

}

@Test
public void save() {
Member member = new Member();
member.setName("spring");


repository.save(member);

Member result = repository.findById(member.getId()).get();
assertThat(member).isEqualTo(result);
}

@Test
public void findByName() {
Member member1 = new Member();
member1.setName("spring1");
repository.save(member1);

Member member2 = new Member();
member2.setName("spring2");
repository.save(member2);

Member result = repository.findByName("spring1").get();

assertThat(result).isEqualTo(member1);

}

@Test
public void findAll() {
Member member1 = new Member();
member1.setName("spring1");
repository.save(member1);

Member member2 = new Member();
member2.setName("spring2");
repository.save(member2);
List<Member> result = repository.findAll();

assertThat(result.size()).isEqualTo(2);
}
}
---------------------------------------------------------

package com.example.spring.repository;

import com.example.spring.domain.Member;

import java.util.*;

public class MemoryMemberRepository implements MemberRepository {
private static Map<Long, Member> store =new HashMap<>();
private static long sequence = 0L;
@Override
public Member save(Member member) {
member.setId(++sequence);
store.put(member.getId(), member);
return member;
}

@Override
public Optional<Member> findById(Long id) {
return Optional.ofNullable(store.get(id));
}

@Override
public Optional<Member> findByName(String name) {
return store.values().stream()
.filter(member -> member.getName().equals(name))
.findAny();
}

@Override
public List<Member> findAll() {
return new ArrayList<>(store.values());
}

public void clearStore() {
store.clear();
}
}

Starting Gradle Daemon...

Gradle Daemon started in 448 ms

> Task :compileJava UP-TO-DATE

> Task :processResources UP-TO-DATE

> Task :classes UP-TO-DATE

> Task :compileTestJava UP-TO-DATE

> Task :processTestResources NO-SOURCE

> Task :testClasses UP-TO-DATE

> Task :test FAILED

Cannot invoke "String.equals(Object)" because the return value of "com.example.spring.domain.Member.getName()" is null

java.lang.NullPointerException: Cannot invoke "String.equals(Object)" because the return value of "com.example.spring.domain.Member.getName()" is null

at com.example.spring.repository.MemoryMemberRepository.lambda$findByName$0(MemoryMemberRepository.java:25)

at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:178)

at java.base/java.util.HashMap$ValueSpliterator.tryAdvance(HashMap.java:1800)

at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:129)

at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:527)

at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:513)

at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)

at java.base/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)

at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)

at java.base/java.util.stream.ReferencePipeline.findAny(ReferencePipeline.java:652)

at com.example.spring.repository.MemoryMemberRepository.findByName(MemoryMemberRepository.java:26)

at com.example.spring.repository.MemoryMemberRepositoryTest.findByName(MemoryMemberRepositoryTest.java:43)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.base/java.lang.reflect.Method.invoke(Method.java:568)

at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:727)

at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)

at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:156)

at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:147)

at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:86)

at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(InterceptingExecutableInvoker.java:103)

at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.lambda$invoke$0(InterceptingExecutableInvoker.java:93)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)

at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:92)

at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:86)

at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$7(TestMethodTestDescriptor.java:217)

at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)

at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:213)

at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:138)

at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:68)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:151)

at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)

at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)

at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)

at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)

at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)

at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)

at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)

at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)

at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)

at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)

at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)

at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)

at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)

at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)

at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)

at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)

at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)

at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107)

at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)

at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)

at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)

at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)

at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114)

at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)

at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)

at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:110)

at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$000(JUnitPlatformTestClassProcessor.java:90)

at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:85)

at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:62)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.base/java.lang.reflect.Method.invoke(Method.java:568)

at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)

at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)

at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)

at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)

at jdk.proxy1/jdk.proxy1.$Proxy2.stop(Unknown Source)

at org.gradle.api.internal.tasks.testing.worker.TestWorker$3.run(TestWorker.java:193)

at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:129)

at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:100)

at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:60)

at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56)

at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:113)

at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:65)

at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69)

at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)

MemoryMemberRepositoryTest > findByName() FAILED

java.lang.NullPointerException at MemoryMemberRepositoryTest.java:43

3 tests completed, 1 failed

FAILURE: Build failed with an exception.

* What went wrong:

Execution failed for task ':test'.

> There were failing tests. See the report at: file:///Users/sunyeong/Downloads/spring/build/reports/tests/test/index.html

* Try:

> Run with --stacktrace option to get the stack trace.

> Run with --info or --debug option to get more log output.

> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 3s

4 actionable tasks: 1 executed, 3 up-to-date

왜 이 에러가 발생하는지 도저히 모르겠습니다 findByName에서 에러가 뜨는데 왜 이런 걸까요?