feat(errors): Add support for duplicate app error (#18)

Author: Joshua-Anderson

errors.go

@@ -27,6 +27,7 @@ const (
 	duplicateUserMsg  = "A user with that username already exists."
 	invalidEmailMsg   = "Enter a valid email address."
 	invalidTagMsg     = "No nodes matched the provided labels"
+	duplicateIDMsg    = "App with this id already exists."
 )
 
 var (
@@ -73,6 +74,8 @@ var (
 	ErrInvalidEmail = errors.New(invalidEmailMsg)
 	// ErrTagNotFound is returned when no node can be found that matches the tag
 	ErrTagNotFound = errors.New(invalidTagMsg)
+	// ErrDuplicateApp is returned when create an app with an ID that already exists
+	ErrDuplicateApp = errors.New(duplicateIDMsg)
 )
 
 func checkForErrors(res *http.Response) error {
@@ -113,6 +116,10 @@ func checkForErrors(res *http.Response) error {
 			return ErrInvalidAppName
 		}
 
+		if scanResponse(bodyMap, "id", []string{duplicateIDMsg}, true) {
+			return ErrDuplicateApp
+		}
+
 		if scanResponse(bodyMap, "key", []string{fieldReqMsg}, true) {
 			return ErrMissingKey
 		}

errors_test.go

@@ -103,6 +103,13 @@ func TestErrors(t *testing.T) {
 			},
 			expected: ErrInvalidAppName,
 		},
+		errorTest{
+			res: &http.Response{
+				StatusCode: 400,
+				Body:       readCloser(`{"id":["App with this id already exists."]}`),
+			},
+			expected: ErrDuplicateApp,
+		},
 		errorTest{
 			res: &http.Response{
 				StatusCode: 400,