feat: TSM 테스트코드 작성

jdbc/src/test/java/org/springframework/transaction/support/TransactionSynchronizationManagerTest.java

@@ -1,6 +1,37 @@
 package org.springframework.transaction.support;
 
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+
+import static org.mockito.Mockito.mock;
+import static org.springframework.transaction.support.TransactionSynchronizationManager.*;
+
 class TransactionSynchronizationManagerTest {
 
+    DataSource dataSource = mock(DataSource.class);
+    Connection connection = mock(Connection.class);
+
+    @Test
+    void 커넥션이_null이라면_null을_반환한다() {
+        Connection resource = getResource(dataSource);
+        Assertions.assertThat(resource).isNull();
+    }
+
+    @Test
+    void 커넥션을_반환한다() {
+        bindResource(dataSource, connection);
+        Connection resource = getResource(dataSource);
+        Assertions.assertThat(resource).isNotNull();
+    }
+
+    @Test
+    void 커넥션을_바인딩한다() {
+        bindResource(dataSource, connection);
+        Connection resource = getResource(dataSource);
+        Assertions.assertThat(resource).isNotNull();
+    }
 
 }