lang-zoo

A polyglot sandbox for testing editor LSP integrations and test runner plugins. Each language directory contains a main source file designed to exercise LSP features (hover, go-to-definition, completions, diagnostics) and a matching test file you can run through your editor's test runner.

Languages

Language	LSP server	Test framework	Run tests
C	clangd	assert.h (hand-rolled)	cc -o test_main test_main.c && ./test_main
C++	clangd	assert (hand-rolled)	c++ -std=c++23 -o test_main test_main.cpp && ./test_main
Go	gopls	testing (stdlib)	go test ./...
Java	jdtls	JUnit 5	via Maven / Gradle
Kotlin	kotlin-language-server	kotlin.test	via Gradle
Lua	lua-language-server	busted	busted (from lua/)
Python	pyright / pylsp	pytest	pytest
Ruby	ruby-lsp	RSpec	rspec
Rust	rust-analyzer	built-in (#[test])	cargo test
TypeScript	typescript-language-server	Vitest	npm i && npm test (from web/)
JavaScript	typescript-language-server	Vitest	same as above
Zig	zls	std.testing	zig test main.zig

Structure

lang-zoo/
├── c/
│   ├── main.c           # LSP test file
│   └── test_main.c      # tests
├── cpp/
│   ├── main.cpp
│   ├── test_main.cpp
│   └── compile_commands.json
├── go/
│   ├── main.go
│   ├── main_test.go
│   └── go.mod
├── java/
│   ├── Main.java
│   └── MainTest.java
├── kotlin/
│   ├── main.kt
│   └── MainTest.kt
├── lua/
│   ├── main.lua
│   ├── .luarc.json
│   └── spec/
│       └── main_spec.lua
├── python/
│   ├── main.py
│   └── test_main.py
├── ruby/
│   ├── main.rb
│   └── spec/
│       └── main_spec.rb
├── rust/
│   ├── Cargo.toml
│   └── src/
│       └── main.rs
├── web/
│   ├── main.js
│   ├── main.ts
│   ├── main.test.js
│   ├── main.test.ts
│   ├── package.json     # Vitest
│   └── tsconfig.json
└── zig/
    └── main.zig

LSP features covered

Each main file is written to exercise:

• Hover — types, doc comments, signatures
• Go-to-definition — structs, interfaces, functions
• Completions — method chains, stdlib APIs
• Diagnostics — intentional unused-variable comments to toggle warnings
• Parameter hints — functions with multiple arguments

Dependencies

Install the test frameworks you want to use:

# Python
pip install pytest

# Ruby
gem install rspec

# Lua
luarocks install busted

# JavaScript / TypeScript
cd web && npm install

Java and Kotlin tests require JUnit 5 on the classpath — use Maven or Gradle to manage dependencies.