fix(coap-core): add mapping for 204 http status to C205_CONTENT code (#129)

Author: szysas

coap-core/src/main/java/com/mbed/coap/packet/Code.java

@@ -106,6 +106,7 @@ public boolean isSuccess() {
         return coapCode >>> 5 == 2;
     }
 
+    @SuppressWarnings("PMD.NcssCount")
     public static Code fromHttp(int httpStatus, Method method) {
 
         switch (httpStatus) {
@@ -127,11 +128,15 @@ public static Code fromHttp(int httpStatus, Method method) {
             case 201:
                 return C201_CREATED;
             case 204:
-                if (method == Method.DELETE) {
-                    return C202_DELETED;
+                switch (method) {
+                    case GET:
+                    case FETCH:
+                        return C205_CONTENT;
+                    case DELETE:
+                        return C202_DELETED;
+                    default:
+                        return C204_CHANGED;
                 }
-                return C204_CHANGED;
-
 
             // REDIRECT (3.xx)
             case 304:

coap-core/src/test/java/com/mbed/coap/packet/CodeTest.java

@@ -112,6 +112,7 @@ public void shouldConvertHttpToCoapCode() {
         assertEquals(Code.C201_CREATED, fromHttp(202, POST));
         assertEquals(Code.C202_DELETED, fromHttp(202, DELETE));
         assertEquals(Code.C202_DELETED, fromHttp(204, DELETE));
+        assertEquals(Code.C205_CONTENT, fromHttp(204, GET));
 
         assertEquals(Code.C203_VALID, fromHttp(304, GET));