test_inotify.lua

local inotify = require 'inotify'

local CHARSET = 'abcdefghijklmnopqrstuvwxyz0123456789'

local charset_idx = 0
local function next_name(len)
    charset_idx = charset_idx + 1

    assert(charset_idx <= #CHARSET)

    return string.rep(string.sub(CHARSET, charset_idx, charset_idx), len)
end

local function make_tmpdir()
    local p = assert(io.popen 'mktemp -d')
    local path = p:read '*l'
    p:close()

    return path
end

local function collect_via_read(handle)
    local got = {}
    while true do
        local events = handle:read()
        if not events or #events == 0 then
            break
        end
        for _, ev in ipairs(events) do
            if ev.name then
                got[ev.name] = true
            end
        end
    end
    os.execute 'sleep 1'
    return got
end

local function compare_sets(expected, received)
    local missing = {}
    local extra = {}
    for name in pairs(expected) do
        if not received[name] then
            missing[#missing + 1] = name
        end
    end
    for name in pairs(received) do
        if not expected[name] then
            extra[#extra + 1] = name
        end
    end
    return missing, extra
end

local function table_count(t)
    local count = 0
    for _ in pairs(t) do
        count = count + 1
    end
    return count
end

local debug = print
-- function debug() end

local function run_round(handle, tmpdir, name_lens)
    local expected = {}
    for i, len in ipairs(name_lens) do
        local name = next_name(len)
        expected[name] = true
        debug('creating', name)
        local f = assert(io.open(tmpdir .. '/' .. name, 'w'))
        f:close()
    end

    -- Events are generated synchronously by the kernel before open() returns,
    -- but give the compat layer a moment just in case.
    os.execute 'sleep 1'

    local got = collect_via_read(handle)

    debug('got ', table_count(got), 'events')
    debug('expected ', table_count(expected), 'events')

    local missing, extra = compare_sets(expected, got)

    -- interestingly enough, if I skip this - it works!
    for name in pairs(expected) do
        os.remove(tmpdir .. '/' .. name)
    end

    return missing, extra
end

local function report_fail(file_count, missing, extra)
    io.stderr:write(string.format(
        'FAIL (files=%d)\n',
        file_count
    ))
    if #missing > 0 then
        io.stderr:write('  missing events:\n')
        for _, name in ipairs(missing) do
            io.stderr:write(string.format('    %s (len=%d)\n', name, #name))
        end
    end
    if #extra > 0 then
        io.stderr:write('  unexpected events:\n')
        for _, name in ipairs(extra) do
            io.stderr:write(string.format('    %s (len=%d)\n', name, #name))
        end
    end
end

local failures = 0

local function test_round(handle, tmpdir, name_lens)
    local missing, extra = run_round(handle, tmpdir, name_lens)
    if #missing > 0 or #extra > 0 then
        failures = failures + 1
        report_fail(#name_lens, missing, extra)
    end
end

local tmpdir = make_tmpdir()
local handle = assert(inotify.init {
    blocking = false,
})
local wd = assert(handle:addwatch(tmpdir, inotify.IN_CREATE))

for _ = 1, 2 do
    local name_lens = {}
    for i = 1, 18 do
        name_lens[i] = 39
    end
    test_round(handle, tmpdir, name_lens)
end

os.exit(failures == 0 and 0 or 1)