Add another test case

struct_utils/map_params_test.go

 package struct_utils_test
 
 import (
+	"fmt"
 	"testing"
 
 	"gitlab.com/uafrica/go-utils/struct_utils"
@@ -61,11 +62,6 @@ func TestAnonymous(t *testing.T) {
 }
 
 func TestMapParams(t *testing.T) {
-	type paramsStruct struct {
-		ID  int64   `json:"id,omitempty"`
-		IDs []int64 `json:"ids,omitempty"`
-	}
-
 	ps := paramsStruct{ID: 123}
 	pm := struct_utils.MapParams(ps)
 	if len(pm) != 1 || pm["id"] != "123" {
@@ -79,4 +75,31 @@ func TestMapParams(t *testing.T) {
 		t.Fatalf("wrong params: %+v != %+v", ps, pm)
 	}
 	t.Logf("ps=%+v -> pm=%+v", ps, pm)
+
+	ps = paramsStruct{X1: xtype{1}, X3: &xtype{3}}
+	pm = struct_utils.MapParams(ps)
+	if len(pm) != 2 || pm["x1"] != ">>1<<" || pm["x3"] != ">>3<<" {
+		t.Fatalf("wrong params: %+v != %+v", ps, pm)
+	}
+	t.Logf("ps=%+v -> pm=%+v", ps, pm)
+}
+
+type paramsStruct struct {
+	ID  int64   `json:"id,omitempty"`
+	IDs []int64 `json:"ids,omitempty"`
+	X1  xtype   `json:"x1,omitempty"`
+	X2  xtype   `json:"x2,omitempty"`
+	X3  *xtype  `json:"x3,omitempty"`
+	X4  *xtype  `json:"x4,omitempty"`
+}
+
+type xtype struct {
+	xvalue int
+}
+
+func (x xtype) String() string {
+	if x.xvalue == 0 {
+		return ""
+	}
+	return fmt.Sprintf(">>%d<<", x.xvalue)
 }