diff --git a/dynamic/spec_test.go b/dynamic/spec_test.go
index 95e76d3..e0eb6a8 100644
--- a/dynamic/spec_test.go
+++ b/dynamic/spec_test.go
@@ -2,8 +2,11 @@ package dynamic
 
 import (
 	"errors"
+	"fmt"
 	"reflect"
 	"testing"
+
+	"git.xdrm.io/go/aicra/api"
 )
 
 func TestInputCheck(t *testing.T) {
@@ -75,7 +78,7 @@ func TestInputCheck(t *testing.T) {
 	}
 
 	for i, tcase := range tcases {
-		t.Run("case."+string(i), func(t *testing.T) {
+		t.Run(fmt.Sprintf("case.%d", i), func(t *testing.T) {
 			// mock spec
 			s := spec{
 				Input:  tcase.Input,
@@ -101,3 +104,113 @@ func TestInputCheck(t *testing.T) {
 		})
 	}
 }
+
+func TestOutputCheck(t *testing.T) {
+	tcases := []struct {
+		Output map[string]reflect.Type
+		Fn     interface{}
+		Err    error
+	}{
+		// no input -> missing api.Error
+		{
+			Output: map[string]reflect.Type{},
+			Fn:     func() {},
+			Err:    ErrMissingHandlerOutput,
+		},
+		// no input -> with api.Error
+		{
+			Output: map[string]reflect.Type{},
+			Fn:     func() api.Error { return api.ErrorSuccess },
+			Err:    nil,
+		},
+		// func can have output if not specified
+		{
+			Output: map[string]reflect.Type{},
+			Fn:     func() (*struct{}, api.Error) { return nil, api.ErrorSuccess },
+			Err:    nil,
+		},
+		// missing output struct in func
+		{
+			Output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			Fn:  func() api.Error { return api.ErrorSuccess },
+			Err: ErrMissingParamOutput,
+		},
+		// output not a pointer
+		{
+			Output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			Fn:  func() (int, api.Error) { return 0, api.ErrorSuccess },
+			Err: ErrMissingParamOutput,
+		},
+		// output not a pointer to struct
+		{
+			Output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			Fn:  func() (*int, api.Error) { return nil, api.ErrorSuccess },
+			Err: ErrMissingParamOutput,
+		},
+		// unexported param name
+		{
+			Output: map[string]reflect.Type{
+				"test1": reflect.TypeOf(int(0)),
+			},
+			Fn:  func() (*struct{}, api.Error) { return nil, api.ErrorSuccess },
+			Err: ErrUnexportedName,
+		},
+		// output field missing
+		{
+			Output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			Fn:  func() (*struct{}, api.Error) { return nil, api.ErrorSuccess },
+			Err: ErrMissingParamFromConfig,
+		},
+		// output field invalid type
+		{
+			Output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			Fn:  func() (*struct{ Test1 string }, api.Error) { return nil, api.ErrorSuccess },
+			Err: ErrWrongParamTypeFromConfig,
+		},
+		// output field valid type
+		{
+			Output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			Fn:  func() (*struct{ Test1 int }, api.Error) { return nil, api.ErrorSuccess },
+			Err: nil,
+		},
+	}
+
+	for i, tcase := range tcases {
+		t.Run(fmt.Sprintf("case.%d", i), func(t *testing.T) {
+			// mock spec
+			s := spec{
+				Input:  nil,
+				Output: tcase.Output,
+			}
+
+			err := s.checkOutput(reflect.ValueOf(tcase.Fn))
+			if err == nil && tcase.Err != nil {
+				t.Errorf("expected an error: '%s'", tcase.Err.Error())
+				t.FailNow()
+			}
+			if err != nil && tcase.Err == nil {
+				t.Errorf("unexpected error: '%s'", err.Error())
+				t.FailNow()
+			}
+
+			if err != nil && tcase.Err != nil {
+				if !errors.Is(err, tcase.Err) {
+					t.Errorf("expected the error <%s> got <%s>", tcase.Err, err)
+					t.FailNow()
+				}
+			}
+		})
+	}
+}