A brief note on module structure. During development I like to create a separate PS1 for every class and resource. I feel that this structure is the cleanest and easiest to manage in source. Here is a snippet of the FileWatcher modules layout.

C:.
│   .gitignore
│   FileWatcher.build.ps1
│   FileWatcher.psd1
│   FileWatcher.psm1
│
├───.vscode
│       settings.json
│
├───Classes
│       BaseFileWatcher.ps1
│
├───DSCResources
│       ProcessFileWatcher.ps1
│       ServiceFileWatcher.ps1
│       WebsiteFileWatcher.ps1

...

This does create some challenges. The biggest is that PowerShell throws a parse error when a class is defined in a script that references an external type. The PowerShell team is tracking the issue here.

To work around this, I have an Invoke-Build script that compiles the files into a completed PS1 and then runs the Pester tests.