This is an example project for building a KeePass 2.x plugin with F#. The repository contains a plugin project (KeePassFSharpPlugin), plus a separate test project (KeePassFSharpPluginTests), which is driven by the Expecto testing framework. The dependencies are managed with Paket. The idea here is that you could test all of the non-UI code of the plugin, using nice F#-native tooling, and then that code would interface with a thin layer over the KeePass plugin API.
To use the plugin, copy the output of the Release build into a directory inside your KeePass plugins
directory, and restart KeePass. You should be able to see Test F# Plugin Options under the Tools
menu, and if you select that menu option, it should show a message box.
To run the tests, simply run the console application that contains the tests.