Test your Neovim plugin from anywhere in the project

lua.lua

-- This assumes that you're testing with plenary, and your test file is in tests/[plugin]_spec.lua
-- Put this in `ftplugin/lua.lua`
vim.keymap.set("n", "<Leader>t", function()
    -- Get the current path and traverse upwards until you find the folder that contains tests/
    local cur_path = vim.fn.expand("%:p:h")
    while cur_path and vim.fn.finddir("tests", cur_path) == "" do
        cur_path = cur_path:match("(.*)/.*")
    end

    if cur_path then
        require("plenary.test_harness").test_directory(cur_path .. "/tests", {
            -- Optionally include a minimal configuration for testing purposes
            minimal_init = cur_path .. "/tests/minimal_init.lua",
        })
    end
end, {
    silent = true,
    buffer = true,
})