Disable nvim's output in tests

[backdround]

I'm testing a plugin which performs searchs. During the tests a headless neovim outputs this to the terminal

Is there a way to mute the stderr output?

[Conni2461]

I've read this like 5 times and i have no idea what you are tying to do, can you elaborate?

Or can you provide a codesnippet? anything?

[backdround]

Sorry for the unclear description, @Conni2461 .

Neovim by default prints search-commands (/) into stderr output when used in the headless mode:

nvim --headless -u NONE -c ":normal! /hello<cr>" -c 'qa!'
# will prints:
/hello<cr>

The problem is when I test a plugin that performs search-commands(/), such output (from search commands) ends up in the tests output because test_harness porxies stderr.

I tried to perform commands with :silent!, but it doesn't seem to work if a plugin calls vim.cmd by itself.

Also, I noticed that tests don't provide such output if only one file is being tested. I didn't manage to figure out why

[backdround]

@Conni2461 minimal example of this test_spec.lua:

local some_plugin_function = function()
  for _=0, 10 do
    -- The culprit!
    vim.cmd("normal! n")
  end
end

describe("issue-example", function()
  it("test", function()
    vim.api.nvim_buf_set_lines(0, 0, 0, true, {
      "some text",
      "in buffer"
    })

    vim.fn.setreg("/", "buffer")
    some_plugin_function()
  end)
end)

stub_spec.lua:

-- can be empty

Result: