✅  Add Servlet Attachment test (#631)

diff --git a/components-starter/camel-servlet-starter/src/test/java/org/apache/camel/component/servlet/springboot/test/ServletAttachmentMultiPartTest.java b/components-starter/camel-servlet-starter/src/test/java/org/apache/camel/component/servlet/springboot/test/ServletAttachmentMultiPartTest.java
new file mode 100644
index 0000000..c424f09
--- /dev/null
+++ b/components-starter/camel-servlet-starter/src/test/java/org/apache/camel/component/servlet/springboot/test/ServletAttachmentMultiPartTest.java
@@ -0,0 +1,86 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.camel.component.servlet.springboot.test;
+
+import org.apache.camel.CamelContext;
+import org.apache.camel.attachment.AttachmentMessage;
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.test.spring.junit5.CamelSpringBootTest;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.util.LinkedMultiValueMap;
+
+import javax.servlet.http.HttpServletRequest;
+
+/**
+ * Testing multipart processing with camel servlet
+ */
+@CamelSpringBootTest
+@SpringBootApplication
+@DirtiesContext
+@ContextConfiguration(classes = ServletAttachmentMultiPartTest.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)
+public class ServletAttachmentMultiPartTest {
+
+    @Autowired
+    private TestRestTemplate restTemplate;
+
+    @Autowired
+    private CamelContext context;
+
+    @BeforeEach
+    public void setup() throws Exception {
+        context.addRoutes(new RouteBuilder() {
+            @Override
+            public void configure() {
+                from("servlet:/test?disableStreamCache=true&attachmentMultipartBinding=true")
+                        .process(exchange -> {
+                            exchange.getIn().setBody(exchange.getIn(AttachmentMessage.class)
+                                    .getAttachments()
+                                    .keySet()
+                                    .iterator()
+                                    .next());
+                        });
+            }
+        });
+    }
+
+    @Test
+    public void testMultipartRequest() throws Exception {
+        String fileName = "attachment";
+        HttpHeaders httpHeaders = new HttpHeaders();
+        httpHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);
+        LinkedMultiValueMap<String, Object> message = new LinkedMultiValueMap<>();
+        message.add(fileName, "Multipart Attachment Test");
+        HttpEntity<LinkedMultiValueMap<String, Object>> httpEntity = new HttpEntity<>(message, httpHeaders);
+        Assertions.assertEquals(fileName, restTemplate.postForEntity("/camel/test", httpEntity, String.class).getBody());
+    }
+
+}
+