Create a Flutter test file under the same directory structure of the source file.
Intall through IDE
On your Intellij IDEA / Android Studio open Settings / Preferences -> Plugins -> Marketplace and type "Flutter Test File Creator "
Install from disk
Download the plugin zip file from plugin homepage or release page
<img src="https://plugins.jetbrains.com/files/19381/screenshot_b35f6802-efc9-4267-ac39-ee562df1ac22" width="500px" /> <img src="https://plugins.jetbrains.com/files/19381/screenshot_42a7be0b-3828-43dd-9e03-e4bd8da0b395" width="500px" /> <img src="https://plugins.jetbrains.com/files/19381/screenshot_9287eb91-5acd-445e-973e-80127fc469c6" width="500px" />