Adding Filter test case

resteasy-spring-boot-starter-test/src/test/java/com/paypal/springboot/resteasy/CommonUseCasesIT.java

@@ -44,6 +44,12 @@ public void happyPathTest() {
         response.then().statusCode(200).body("timestamp", notNullValue()).body("echoText", equalTo("is there anybody out there?"));
     }
 
+    @Test
+    public void filterTest() {
+        Response response = given().body("is there anybody out there?").header("ping", "ping").post("/echo");
+        response.then().statusCode(200).body("timestamp", notNullValue()).body("echoText", equalTo("is there anybody out there?")).header("pong", equalTo("pong"));
+    }
+
     @Test
     public void invalidUriPathTest() {
         // Notice "eco" is supposed to result in 404

sample-app/src/main/java/com/sample/app/CustomContainerResponseFilter.java

@@ -0,0 +1,41 @@
+package com.sample.app;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import javax.ws.rs.container.ContainerRequestContext;
+import javax.ws.rs.container.ContainerResponseContext;
+import javax.ws.rs.container.ContainerResponseFilter;
+import javax.ws.rs.ext.Provider;
+import java.io.IOException;
+
+/**
+ * Custom container request filter just to
+ * exercise Spring beans as providers and,
+ * specifically, in this case, as a filter.
+ *
+ * @author Fabio Carvalho ([email protected] or [email protected])
+ */
+@Component
+@Provider
+public class CustomContainerResponseFilter implements ContainerResponseFilter {
+
+    @Autowired
+    private CustomSingletonBean customSingletonBean;
+
+    @Override
+    public void filter(ContainerRequestContext requestContext, ContainerResponseContext responseContext) throws IOException {
+
+        // This will cause a NPE if this bean couldn't be injected,
+        // and that is all we want to check. No need for assertions here
+        customSingletonBean.amIAlive();
+
+        // Checks if request has a HTTP header named "ping".
+        // If it does, adds an HTTP header named "pong" to the response.
+        // The header value is irrelevant.
+        if(requestContext.getHeaderString("ping") != null) {
+            responseContext.getHeaders().add("pong", "pong");
+        }
+    }
+
+}