I found an issue on Windows with the package name generated for test classes.

Steps to recreate

1. Open Java class located at C:\chris\wc\sample-multi-module\library\src\main\java\com\example\multimodule\service\MyService.java
2. Run command "Command: Java: Create/Open Test Class"
3. Test Class is generated with the package declaration package mple-multi-module\library\src\test\java\com\example\multimodule\service;

Root Cause

In a nutshell, the code uses uri.fsPath for the path and assumes the path separator is /, however on Windows the path separator (frustratingly) is \

Proposed Fix

This proposed fix normalizes the path by converting all \ to / in the file path once, and for consistency uses that normalized path for all package name generation functionality.

I tested generating a test class on both Windows and Linux, and this fix generated the correct package name in both!