Not able to use mirrors in flutter package

I created a new flutter package project.

Trying to use dart:mirrors in tests, but it is not visible...

Any guess why that happen?

Here is my pubspec:

name: testName
description: A new Flutter package.
version: 0.0.1
author:
homepage:

environment:
  sdk: ">=2.12.0 <3.0.0"
  flutter: ">=1.17.0"

dependencies:
  flutter:
    sdk: flutter
  equatable: 2.0.0

dev_dependencies:
  flutter_test:
    sdk: flutter