add test

Author: KTC-YoheiMiyashita

dbAndCsvBatch/src/test/java/com/example/batch/DbAndCsvBatchAppTest.java

@@ -0,0 +1,32 @@
+package com.example.batch;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.TestPropertySource;
+
+@SpringBootTest
+@TestPropertySource(
+    properties = {
+      "spring.batch.job.enabled=false",
+      "spring.datasource.mysqlmain.url=jdbc:mysql://localhost:3306/sampledb",
+      "spring.datasource.mysqlmain.username=sampleuser",
+      "spring.datasource.mysqlmain.password=samplepassword"
+    })
+class DbAndCsvBatchAppTest {
+
+  @Test
+  void testMainMethod() {
+    // Arrange
+    String[] args = {"--spring.batch.job.name=DB_TO_CSV", "--spring.profiles.active=local"};
+    System.setProperty("sun.java.command", String.join(" ", args));
+
+    // Act
+    DbAndCsvBatchApp.main(args);
+
+    // Assert
+    // Main method execution doesn't throw exceptions
+  }
+}