it('shutdown resolves shutdown_promise and clears fields', function()
    local server = OpencodeServer.new()
    local exit_callback
    
    -- Mock vim.system to capture the exit callback
    vim.system = function(cmd, opts, on_exit)
      exit_callback = on_exit
      return { pid = 2, kill = function() end }
    end
    
    -- Spawn the server so the exit callback is set up
    server:spawn({
      cwd = '.',
      on_ready = function() end,
      on_error = function() end,
      on_exit = function() end,
    })
    
    local resolved = false
    server:get_shutdown_promise():and_then(function()
      resolved = true
    end)
    
    -- Call shutdown (sends SIGTERM)
    server:shutdown()
    
    -- Simulate the process exiting by calling the exit callback
    vim.schedule(function()
      exit_callback({ code = 0, signal = 0 })
    end)
    
    vim.wait(100, function()
      return resolved
    end)
    
    assert.is_true(resolved)
    assert.is_nil(server.job)
    assert.is_nil(server.url)
    assert.is_nil(server.handle)
  end)