[fix]:[添加java测试代码]

pom.xml

@@ -11,4 +11,12 @@
     <maven.compiler.source>17</maven.compiler.source>
     <maven.compiler.target>17</maven.compiler.target>
   </properties>
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.12.2</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
 </project>

src/main/java/com/example/App.java

@@ -4,5 +4,10 @@ public class App {
     public static void main(String[] args) {
         System.out.println("Hello, World!");
     }
+
+    public String greet() {
+        return "Hello, World!";
+    }
+
 }
 

src/test/java/com/example/AppTest.java

@@ -0,0 +1,8 @@
+package com.example;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+public class AppTest {
+    @Test public void testGreet() { App app = new App(); assertEquals("Hello, World!", app.greet()); }
+}