优化结构

internal/service/system/department_test.go

@@ -0,0 +1,15 @@
+package system
+
+import (
+	"kra/internal/biz/system"
+	"testing"
+)
+
+func TestDepartmentResponsePreservesNilAndEmptyChildren(t *testing.T) {
+	if got := departmentResponse(&system.Department{}).Children; got != nil {
+		t.Fatalf("single/search department children = %#v, want nil", got)
+	}
+	if got := departmentResponse(&system.Department{Children: []*system.Department{}}).Children; got == nil || len(got) != 0 {
+		t.Fatalf("tree leaf children = %#v, want empty slice", got)
+	}
+}