# Testing Julia REPL in a libuv spawn call

**URL:** <https://discourse.julialang.org/t/testing-julia-repl-in-a-libuv-spawn-call/123980>\
**Category:** General Usage\
**Tags:** question, testing, repl, lua, libuv\
**Created:** [December 19, 2024, 6:40am UTC](https://discourse.julialang.org/t/testing-julia-repl-in-a-libuv-spawn-call/123980 "2024-12-19T06:40:18Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![klafyvel](https://avatars.discourse-cdn.com/v4/letter/k/a587f6/32.png) [@klafyvel](https://discourse.julialang.org/u/klafyvel)\
**Post date:** [December 19, 2024, 6:40am UTC](https://discourse.julialang.org/t/testing-julia-repl-in-a-libuv-spawn-call/123980/1 "2024-12-19T06:40:18Z")

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Hi there, I might use a bit of help with Lua, libuv, and the Julia REPL (I initially posted on slack, but folk rightfully pointed that this is better suited here). For context, I am writing integration tests for neovim’s plugin for REPLSmuggler.jl. I have julia running through a `uv.spawn` call, for which I make available to lua `stdin` `stdout` and `stderr` (see [here](https://github.com/Klafyvel/nvim-smuggler/pull/58/files#diff-e1f7389b0697ed6b592ff77b8e71d6b8fa18cdeb6f03ae6307556d2d11e4dfcfR19) ). It kind of works if I write directly to julia’s stdin and check its stdout (essentially, this first test passes: [feat(tests): Add base architecture for testing the module. by Klafyvel · Pull Request #58 · Klafyvel/nvim-smuggler · GitHub](https://github.com/Klafyvel/nvim-smuggler/pull/58/files#diff-f1de5cfebf8d6b864e43f4ab5d1f8ecec7b4edf8a25ee2ab29dd935f17d3567aR46)), but when I try printing stuff through REPLSmuggler, nothing happens (same if I try to e.g. write in a file). Since my tests also show me that I don’t get usual stuff I would expect from the Julia REPL (for example the `julia>` prompt), I guess this means the REPL is in a different state from what I get if I just run it from a terminal. This might be a reason why the test codes are not being run, as REPLSmuggler.jl depends on the internals of LineEditREPL.So my questions are:

1. Is Julia still using LineEditREPL when Julia runs as a subprocess, and its stdio are pipes?
2. If not, how can I make it use LineEditREPL?