Implements RegisterAccountProcessor

src/main/java/com/yam/app/account/application/RegisterAccountCommand.java

@@ -0,0 +1,17 @@
+package com.yam.app.account.application;
+
+import lombok.Getter;
+
+@Getter
+public final class RegisterAccountCommand {
+
+    private final String email;
+    private final String nickname;
+    private final String password;
+
+    public RegisterAccountCommand(String email, String nickname, String password) {
+        this.email = email;
+        this.nickname = nickname;
+        this.password = password;
+    }
+}

src/main/java/com/yam/app/account/domain/Account.java

@@ -0,0 +1,19 @@
+package com.yam.app.account.domain;
+
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public final class Account {
+    private Long id;
+    private String email;
+    private String nickname;
+    private String password;
+
+    public Account(String email, String nickname, String password) {
+        this.email = email;
+        this.nickname = nickname;
+        this.password = password;
+    }
+}

src/main/java/com/yam/app/account/domain/AccountRepository.java

@@ -0,0 +1,10 @@
+package com.yam.app.account.domain;
+
+public interface AccountRepository {
+
+    boolean existsByEmail(String email);
+
+    boolean existsByNickname(String nickname);
+
+    Account save(Account entity);
+}

src/main/java/com/yam/app/account/domain/RegisterAccountProcessor.java

@@ -0,0 +1,21 @@
+package com.yam.app.account.domain;
+
+public final class RegisterAccountProcessor {
+
+    private final AccountRepository accountRepository;
+
+    public RegisterAccountProcessor(AccountRepository accountRepository) {
+        this.accountRepository = accountRepository;
+    }
+
+    public Account process(String email, String nickname, String password) {
+        if (accountRepository.existsByEmail(email)) {
+            throw new IllegalStateException();
+        }
+        if (accountRepository.existsByNickname(nickname)) {
+            throw new IllegalStateException();
+        }
+
+        return accountRepository.save(new Account(email, nickname, password));
+    }
+}

src/main/java/com/yam/app/configuration/DatabaseConfiguration.java

@@ -1,4 +1,4 @@
-package com.yam.app.account.infrastructure;
+package com.yam.app.configuration;
 
 import javax.sql.DataSource;
 import org.springframework.context.annotation.Bean;

src/test/java/com/yam/app/account/domain/RegisterAccountProcessorTest.java

@@ -0,0 +1,83 @@
+package com.yam.app.account.domain;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+
+import com.yam.app.account.application.RegisterAccountCommand;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicLong;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.DynamicTest;
+import org.junit.jupiter.api.TestFactory;
+
+@DisplayName("회원가입 도메인 서비스")
+class RegisterAccountProcessorTest {
+
+    @TestFactory
+    @DisplayName("회원가입 시나리오")
+    Collection<DynamicTest> register_account_scenarios() {
+        var repository = new AccountRepositoryStub();
+        var processor = new RegisterAccountProcessor(repository);
+        return Arrays.asList(
+            DynamicTest.dynamicTest("회원가입에 성공한다.", () -> {
+                // Arrange
+                var command = new RegisterAccountCommand("rebwon@gmail.com", "rebwon", "password!");
+
+                // Act
+                Account account = processor.process(command.getEmail(), command.getNickname(),
+                    command.getPassword());
+
+                // Assert
+                assertThat(account.getId()).isEqualTo(1L);
+            }),
+            DynamicTest.dynamicTest("이메일 검증에 실패하여 예외를 리턴한다.", () -> {
+                // Arrange
+                var command = new RegisterAccountCommand("rebwon@gmail.com", "rebwon", "password!");
+
+                // Act & Assert
+                assertThatExceptionOfType(IllegalStateException.class)
+                    .isThrownBy(() -> processor.process(command.getEmail(), command.getNickname(),
+                        command.getPassword()));
+            }),
+            DynamicTest.dynamicTest("닉네임 검증에 실패하여 예외를 리턴한다.", () -> {
+                // Arrange
+                var command = new RegisterAccountCommand("kitty@gmail.com", "rebwon", "password!");
+
+                // Act & Assert
+                assertThatExceptionOfType(IllegalStateException.class)
+                    .isThrownBy(() -> processor.process(command.getEmail(), command.getNickname(),
+                        command.getPassword()));
+            })
+        );
+    }
+
+    private static class AccountRepositoryStub implements AccountRepository {
+
+        private final Map<Long, Account> data = new ConcurrentHashMap<>();
+        private final AtomicLong idGenerator = new AtomicLong();
+
+        @Override
+        public boolean existsByEmail(String email) {
+            return data.values().stream()
+                .anyMatch(account -> account.getEmail().equals(email));
+        }
+
+        @Override
+        public boolean existsByNickname(String nickname) {
+            return data.values().stream()
+                .anyMatch(account -> account.getNickname().equals(nickname));
+        }
+
+        @Override
+        public Account save(Account entity) {
+            if (entity.getId() == null) {
+                entity.setId(idGenerator.incrementAndGet());
+                data.put(entity.getId(), entity);
+            }
+            return data.putIfAbsent(entity.getId(), entity);
+        }
+    }
+}