Merge pull request #1511 from mesg-foundation/feature/null-parameter-…

…value

Fix bug when Value_NullValue is not taking into account

service/service_parameter.go

@@ -20,13 +20,13 @@ func validateServiceParameters(parameters []*Service_Parameter, data *types.Stru
 			errs = append(errs, err)
 		}
 	}
-
 	return errs.ErrorOrNil()
 }
 
 // Validate checks if service parameter hash proper types for arrays and objects.
 func (p *Service_Parameter) Validate(value *types.Value) error {
-	if value == nil {
+	_, isNull := value.GetKind().(*types.Value_NullValue)
+	if value == nil || isNull {
 		if p.Optional {
 			return nil
 		}

service/service_parameter_test.go

@@ -238,6 +238,24 @@ func TestValidate(t *testing.T) {
 			},
 			expecterr: true,
 		},
+		{
+			name: "optional null",
+			params: []*Service_Parameter{
+				{
+					Key:      "key",
+					Type:     "Object",
+					Optional: true,
+				},
+			},
+			data: &types.Struct{
+				Fields: map[string]*types.Value{
+					"key": {
+						Kind: &types.Value_NullValue{},
+					},
+				},
+			},
+			expecterr: false,
+		},
 	}
 	for _, tt := range tests {
 		tt := tt