From a9d960076df627a00beef78f93c64ccb807236f3 Mon Sep 17 00:00:00 2001
From: Alexander Turenko <alexander.turenko@tarantool.org>
Date: Wed, 28 Sep 2022 15:04:28 +0300
Subject: [PATCH] test: add a helper for testing interactive mode
A basic (and pretty useless) example:
```lua
local it = require('test.luatest_helpers.interactive_tarantool')
local child = it.new()
child:execute_command('6 * 7')
local res = child:read_response()
t.assert_equals(res, 42)
child:close()
```
The module also contains `:read_line()`, `:assert_line()` helpers for
testing output directly: for example, when we need to catch a print()
from a background fiber. It provides has constants related to terminal's
control sequences.
A real usage can be seen in a next commit.
Part of #7169
NO_DOC=no user visible changes
NO_TEST=not applicable, it is a testing helper
NO_CHANGELOG=no user visible changes
---
.../luatest_helpers/interactive_tarantool.lua | 300 ++++++++++++++++++
1 file changed, 300 insertions(+)
create mode 100644 test/luatest_helpers/interactive_tarantool.lua
diff --git a/test/luatest_helpers/interactive_tarantool.lua b/test/luatest_helpers/interactive_tarantool.lua
new file mode 100644
index 0000000000..5218607a68
--- /dev/null
+++ b/test/luatest_helpers/interactive_tarantool.lua
@@ -0,0 +1,300 @@
+-- A set of helpers to ease testing of tarantool's interactive
+-- mode.
+
+local fun = require('fun')
+local fiber = require('fiber')
+local log = require('log')
+local yaml = require('yaml')
+local popen = require('popen')
+
+-- Default timeout for expecting an input on child's stdout.
+--
+-- Testing code shouldn't just hang, it rather should raise a
+-- meaningful error for debugging.
+local TIMEOUT = 5
+
+local M = {}
+
+local mt = {}
+mt.__index = mt
+
+-- {{{ Instance methods
+
+function mt._start_stderr_logger(self)
+ local f = fiber.create(function()
+ local fiber_name = "child's stderr logger"
+ fiber.name(fiber_name, {truncate = true})
+
+ while true do
+ local chunk, err = self.ph:read({stderr = true})
+ if chunk == nil then
+ log.warn(('%s: got error, exitting: %s'):format(
+ fiber_name, tostring(err)))
+ break
+ end
+ if chunk == '' then
+ log.info(('%s: got EOF, exitting'):format(fiber_name))
+ break
+ end
+ for _, line in ipairs(chunk:rstrip('\n'):split('\n')) do
+ log.warn(('%s: %s'):format(fiber_name, line))
+ end
+ end
+ end)
+ self._stderr_logger = f
+end
+
+function mt._stop_stderr_logger(self)
+ self._stderr_logger:cancel()
+ self._stderr_logger = nil
+end
+
+function mt.read_chunk(self, opts)
+ local opts = opts or {}
+ local deadline = opts.deadline or (fiber.clock() + TIMEOUT)
+
+ local chunk, err = self.ph:read({timeout = TIMEOUT})
+ if chunk == nil then
+ error(err)
+ end
+ if chunk == '' then
+ error('Unexpected EOF')
+ end
+ if fiber.clock() > deadline then
+ error('Timed out')
+ end
+ self._readahead_buffer = self._readahead_buffer .. chunk
+ log.info(("child's stdout logger: %s"):format(M.escape_control(chunk)))
+end
+
+function mt.read_line(self, opts)
+ local opts = opts or {}
+ local deadline = opts.deadline or (fiber.clock() + TIMEOUT)
+
+ while not self._readahead_buffer:find('\n') do
+ self:read_chunk({deadline = deadline})
+ end
+ local line, new_buffer = unpack(self._readahead_buffer:split('\n', 1))
+ self._readahead_buffer = new_buffer
+ return line
+end
+
+-- Returns all readed lines (including expected one).
+function mt.read_until_line(self, exp_line, opts)
+ local opts = opts or {}
+ local deadline = opts.deadline or (fiber.clock() + TIMEOUT)
+
+ local res = {}
+
+ repeat
+ local line = self:read_line({deadline = deadline})
+ table.insert(res, line)
+ until line == exp_line
+
+ return res
+end
+
+function mt.assert_line(self, exp_line, opts)
+ local opts = opts or {}
+ local deadline = opts.deadline or (fiber.clock() + TIMEOUT)
+
+ local line = self:read_line({deadline = deadline})
+ if line ~= exp_line then
+ error(('Unexpected line %q, expected %q'):format(line, exp_line))
+ end
+end
+
+function mt.assert_data(self, exp_data, opts)
+ local opts = opts or {}
+ local deadline = opts.deadline or (fiber.clock() + TIMEOUT)
+
+ while #self._readahead_buffer < #exp_data do
+ self:read_chunk({deadline = deadline})
+ end
+ local data = self._readahead_buffer:sub(1, #exp_data)
+ local new_buffer = self._readahead_buffer:sub(#exp_data + 1)
+ self._readahead_buffer = new_buffer
+ if data ~= exp_data then
+ error(('Unexpected data %q, expected %q'):format(data, exp_data))
+ end
+end
+
+-- ReadLine echoes commands to stdout. It is easier to match the
+-- echo against the original command, when the command is a
+-- one-liner. Let's replace newlines with spaces.
+--
+-- Add a line feed at the end to send the command for execution.
+local function _prepare_command_for_write(command)
+ return command:rstrip('\n'):gsub('\n', ' ') .. '\n'
+end
+
+-- ReadLine determines terminal's ability to wrap long lines and
+-- may perform the wrapping on its own. It adds carriage return,
+-- spaces and may duplicate some characters.
+--
+-- Observed behavior is different on different readline version:
+--
+-- * ReadLine 8: lean on terminal's wrapping.
+-- * ReadLine 7: x<CR><duplicate x>, extra spaces.
+-- * ReadLine 6: <space><CR>.
+--
+-- This function drop duplicates that goes in row, strips <CR> and
+-- spaces. Applying of this function to a source command and
+-- readline's echoed command allows to compare them for equality.
+local function _prepare_command_for_compare(x)
+ x = x:gsub(' ', ''):gsub(M.CR, '')
+ local acc = fun.iter(x):reduce(function(acc, c)
+ if acc[#acc] ~= c then
+ table.insert(acc, c)
+ end
+ return acc
+ end, {})
+ return table.concat(acc)
+end
+
+function mt._assert_command_echo(self, prepared_command, opts)
+ local opts = opts or {}
+ local deadline = opts.deadline or (fiber.clock() + TIMEOUT)
+
+ local prompt = 'tarantool> '
+ local exp_echo = prompt .. prepared_command:rstrip('\n')
+ local echo = self:read_line({deadline = deadline})
+
+ -- If readline wraps the line, prepare the commands for
+ -- compare.
+ local comment = ''
+ if echo:find(M.CR) ~= nil then
+ exp_echo = _prepare_command_for_compare(exp_echo)
+ echo = _prepare_command_for_compare(echo)
+ comment = ' (the commands are mangled for the comparison)'
+ end
+
+ if echo ~= exp_echo then
+ error(('Unexpected command echo %q, expected %q%s'):format(
+ echo, exp_echo, comment))
+ end
+end
+
+function mt.execute_command(self, command, opts)
+ local opts = opts or {}
+ local deadline = opts.deadline or (fiber.clock() + TIMEOUT)
+
+ local prepared_command = _prepare_command_for_write(command)
+ self.ph:write(prepared_command)
+ self:_assert_command_echo(prepared_command, {deadline = deadline})
+end
+
+-- Ignores output before yaml start document marks, because
+-- print() output may appear before it.
+function mt.read_response(self, opts)
+ local opts = opts or {}
+ local deadline = opts.deadline or (fiber.clock() + TIMEOUT)
+
+ self:read_until_line('---', {deadline = deadline})
+ local lines = self:read_until_line('...', {deadline = deadline})
+ self:assert_line('', {deadline = deadline})
+
+ -- Handle empty response.
+ if #lines == 1 then
+ return
+ end
+
+ local raw_reply = '---\n' .. table.concat(lines, '\n') .. '\n'
+ local reply = yaml.decode(raw_reply)
+ return unpack(reply, 1, table.maxn(reply))
+end
+
+function mt.assert_empty_response(self, opts)
+ local reply = {self:read_response(opts)}
+ if table.maxn(reply) ~= 0 then
+ error(('Unexpected non-empty response:\n%s'):format(yaml.encode(reply)))
+ end
+end
+
+function mt.close(self)
+ self:_stop_stderr_logger()
+ self.ph:close()
+end
+
+-- }}} Instance methods
+
+-- {{{ Module functions
+
+function M.escape_control(str)
+ return str
+ :gsub(M.TAB, '<TAB>')
+ :gsub(M.LF, '<LF>')
+ :gsub(M.CR, '<CR>')
+ :gsub(M.ESC, '<ESC>')
+end
+
+function M.new(opts)
+ local opts = opts or {}
+ local args = opts.args or {}
+
+ local tarantool_exe = arg[-1]
+ local ph = popen.new(fun.chain({tarantool_exe, '-i'}, args):totable(), {
+ stdin = popen.opts.PIPE,
+ stdout = popen.opts.PIPE,
+ stderr = popen.opts.PIPE,
+ env = {
+ -- Don't know why, but without defined TERM environment
+ -- variable readline doesn't accept INPUTRC environment
+ -- variable.
+ TERM = 'xterm',
+ -- Prevent system/user inputrc configuration file from
+ -- influence testing code. In particular, if
+ -- horizontal-scroll-mode is enabled,
+ -- _assert_command_echo() on a long command will fail
+ -- (because the command in the echo output will be
+ -- trimmed).
+ INPUTRC = '/dev/null',
+ },
+ })
+
+ local res = setmetatable({
+ ph = ph,
+ _readahead_buffer = '',
+ }, mt)
+
+ -- Log child's stderr.
+ res:_start_stderr_logger()
+
+ -- Write a command and ignore the echoed output.
+ --
+ -- ReadLine 6 writes <ESC>[?1034h at beginning, it may hit
+ -- assertions on the child's output.
+ --
+ -- This sequence of charcters is smm ('set meta mode')
+ -- terminal capacity value. It has relation to writing
+ -- characters out of the ASCII range -- ones with 8th bit set,
+ -- but its description is vague. See terminfo(5).
+ res.ph:write("'Hello!'\n")
+ res:read_line()
+ assert(res:read_response() == 'Hello!')
+
+ -- Disable stdout line buffering in the child.
+ res:execute_command("io.stdout:setvbuf('no')")
+ assert(res:read_response(), true)
+
+ return res
+end
+
+-- }}} Module functions
+
+-- {{{ Module constants
+
+-- It may be different for remote console, but the module supports
+-- only local console for now.
+M.PROMPT = 'tarantool> '
+
+M.TAB = '\x09'
+M.LF = '\x0a'
+M.CR = '\x0d'
+M.ESC = '\x1b'
+
+M.ERASE_IN_LINE = M.ESC .. '[K'
+
+-- }}} Module constants
+
+return M
--
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