New error handling added to server and decorator module in data package

internal/server/data/decorator.go

@@ -20,6 +20,7 @@ import (
 	"net/http"
 
 	"github.com/BBVA/kapow/internal/server/model"
+	"github.com/BBVA/kapow/internal/server/srverrors"
 	"github.com/gorilla/mux"
 )
 
@@ -39,7 +40,7 @@ func checkHandler(fn resourceHandler) func(http.ResponseWriter, *http.Request) {
 		if h, ok := Handlers.Get(handlerID); ok {
 			fn(w, r, h)
 		} else {
-			w.WriteHeader(http.StatusNotFound)
+			srverrors.WriteErrorResponse(http.StatusNotFound, "Handler ID Not Found", w)
 		}
 	}
 }

internal/server/data/decorator_test.go

@@ -127,9 +127,8 @@ func TestCheckHandlerReturnsAFunctionsThat404sWhenHandlerDoesNotExist(t *testing
 
 	fn(w, r)
 
-	res := w.Result()
-	if res.StatusCode != http.StatusNotFound {
-		t.Errorf("Status code mismatch. Expected 404. Got %d", res.StatusCode)
+	for _, e := range checkErrorResponse(w.Result(), http.StatusNotFound, "Handler ID Not Found") {
+		t.Error(e.Error())
 	}
 }
 

internal/server/data/server.go

@@ -20,6 +20,7 @@ import (
 	"log"
 	"net/http"
 
+	"github.com/BBVA/kapow/internal/server/srverrors"
 	"github.com/gorilla/mux"
 )
 
@@ -36,7 +37,9 @@ func configRouter(rs []routeSpec) (r *mux.Router) {
 	}
 	r.HandleFunc(
 		"/handlers/{handlerID}/{resource:.*}",
-		func(w http.ResponseWriter, r *http.Request) { w.WriteHeader(http.StatusBadRequest) })
+		func(w http.ResponseWriter, r *http.Request) {
+			srverrors.WriteErrorResponse(http.StatusBadRequest, "Invalid Resource Path", w)
+		})
 	return r
 }
 

internal/server/data/server_test.go

@@ -17,13 +17,40 @@
 package data
 
 import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"testing"
 
 	"github.com/BBVA/kapow/internal/server/model"
+	"github.com/BBVA/kapow/internal/server/srverrors"
 )
 
+func checkErrorResponse(r *http.Response, expectedErrcode int, expectedReason string) []error {
+	errList := make([]error, 0)
+
+	if r.StatusCode != expectedErrcode {
+		errList = append(errList, fmt.Errorf("HTTP status mismatch. Expected: %d, got: %d", expectedErrcode, r.StatusCode))
+	}
+
+	if v := r.Header.Get("Content-Type"); v != "application/json; charset=utf-8" {
+		errList = append(errList, fmt.Errorf("Content-Type header mismatch. Expected: %q, got: %q", "application/json; charset=utf-8", v))
+	}
+
+	errMsg := srverrors.ServerErrMessage{}
+	if bodyBytes, err := ioutil.ReadAll(r.Body); err != nil {
+		errList = append(errList, fmt.Errorf("Unexpected error reading response body: %v", err))
+	} else if err := json.Unmarshal(bodyBytes, &errMsg); err != nil {
+		errList = append(errList, fmt.Errorf("Response body contains invalid JSON entity: %v", err))
+	} else if errMsg.Reason != expectedReason {
+		errList = append(errList, fmt.Errorf("Unexpected reason in response. Expected: %q, got: %q", expectedReason, errMsg.Reason))
+	}
+
+	return errList
+}
+
 func TestConfigRouterReturnsRouterWithDecoratedRoutes(t *testing.T) {
 	var handlerID string
 	rs := []routeSpec{
@@ -50,8 +77,7 @@ func TestConfigRouterReturnsRouterThat400sOnUnconfiguredResources(t *testing.T)
 
 	m.ServeHTTP(w, httptest.NewRequest("GET", "/handlers/FOO/dummy", nil))
 
-	res := w.Result()
-	if res.StatusCode != http.StatusBadRequest {
-		t.Errorf("Status code mismatch. Expected 400. Got %d", res.StatusCode)
+	for _, e := range checkErrorResponse(w.Result(), http.StatusBadRequest, "Invalid Resource Path") {
+		t.Error(e.Error())
 	}
 }