Note:
  The integration_test package is part of the Flutter SDK itself. 
  To use it, make sure that you update your app’s pubspec file
  to include this package as one of your dev_dependencies. 
  For an example, see the Project setup section below.

Overview

Unit tests, widget tests, and integration tests

There are three types of tests that Flutter supports.
A unit test verifies the behavior of a method or class.
A widget test verifies the behavior of Flutter widgets
without running the app itself. An integration test (also
called end-to-end testing or GUI testing) runs the full app.

Hosts and targets

During development, you are probably writing the code
on a desktop computer, called the host machine,
and running the app on a mobile device, browser,
or desktop application, called the target device.
(If you are using a web
browser or desktop application,
the host machine is also the target device.)

integration_test