Testing Input Widgets is incredibly slow

[sealor]

I wrote some custom Input widgets. Unfortunately, testing them is really really slow.

Typing in a simple text like This is my text! needs ~15 seconds on my machine. I increasingly think about removing those test. But, of cause this would lead to other issues ... Could you please improve the execution time?

Example:
performance_issue_app.py

import cProfile
import pstats
import unittest

import pytest
from textual.app import App, ComposeResult
from textual.pilot import Pilot
from textual.widgets import Input


class PerformanceIssueApp(App):
    def compose(self) -> ComposeResult:
        yield Input().focus()


class PerformanceIssueAppTest(unittest.IsolatedAsyncioTestCase):
    async def test_type_text(self):
        app = PerformanceIssueApp()
        async with app.run_test() as pilot:  # type:Pilot
            await pilot.press(*[c for c in "This is my text!"])

            input_widget = pilot.app.query_exactly_one(Input)
            self.assertEqual("This is my text!", input_widget.value)


if __name__ == "__main__":
    with cProfile.Profile() as pr:
        try:
            pytest.main(["-v", __file__])
        finally:
            pstats.Stats(pr).sort_stats(pstats.SortKey.CUMULATIVE).print_stats(50)

Output:

============================= test session starts ==============================
platform linux -- Python 3.12.3, pytest-8.3.3, pluggy-1.5.0 -- /home/stefan/test/.venv/bin/python
cachedir: .pytest_cache
rootdir: /home/stefan/test
configfile: pyproject.toml
collecting ... collected 1 item

performance_app.py::PerformanceIssueAppTest::test_type_text PASSED       [100%]

============================== 1 passed in 14.99s ==============================
         1195031 function calls (1186548 primitive calls) in 15.045 seconds

   Ordered by: cumulative time
   List reduced from 2572 to 50 due to restriction <50>

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000   15.048   15.048 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/config/__init__.py:139(main)
   251/71    0.000    0.000   15.033    0.212 /home/stefan/test/.venv/lib/python3.12/site-packages/pluggy/_manager.py:111(_hookexec)
   251/71    0.001    0.000   15.033    0.212 /home/stefan/test/.venv/lib/python3.12/site-packages/pluggy/_callers.py:53(_multicall)
     94/2    0.000    0.000   15.032    7.516 /home/stefan/test/.venv/lib/python3.12/site-packages/pluggy/_hooks.py:498(__call__)
        1    0.000    0.000   15.006   15.006 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/main.py:329(pytest_cmdline_main)
        1    0.000    0.000   15.006   15.006 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/main.py:270(wrap_session)
        1    0.000    0.000   14.993   14.993 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/main.py:333(_main)
      7/6    0.000    0.000   14.991    2.499 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/runner.py:319(from_call)
        1    0.000    0.000   14.985   14.985 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/main.py:350(pytest_runtestloop)
        1    0.000    0.000   14.985   14.985 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/runner.py:110(pytest_runtest_protocol)
        1    0.000    0.000   14.984   14.984 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/runner.py:118(runtestprotocol)
        3    0.000    0.000   14.984    4.995 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/runner.py:226(call_and_report)
        3    0.000    0.000   14.984    4.995 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/runner.py:242(<lambda>)
        1    0.000    0.000   14.983   14.983 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/runner.py:163(pytest_runtest_call)
        1    0.000    0.000   14.983   14.983 /home/stefan/test/.venv/lib/python3.12/site-packages/_pytest/unittest.py:322(runtest)
        1    0.000    0.000   14.983   14.983 /usr/lib/python3.12/unittest/case.py:689(__call__)
        1    0.000    0.000   14.983   14.983 /usr/lib/python3.12/unittest/async_case.py:128(run)
        1    0.000    0.000   14.982   14.982 /usr/lib/python3.12/unittest/case.py:599(run)
        3    0.000    0.000   14.982    4.994 /usr/lib/python3.12/asyncio/runners.py:86(run)
        5    0.000    0.000   14.980    2.996 /usr/lib/python3.12/asyncio/base_events.py:651(run_until_complete)
        5    0.004    0.001   14.980    2.996 /usr/lib/python3.12/asyncio/base_events.py:627(run_forever)
        1    0.000    0.000   14.980   14.980 /usr/lib/python3.12/unittest/async_case.py:89(_callTestMethod)
        1    0.000    0.000   14.980   14.980 /usr/lib/python3.12/unittest/async_case.py:109(_callMaybeAsync)
     1628    0.059    0.000   14.976    0.009 /usr/lib/python3.12/asyncio/base_events.py:1910(_run_once)
     1628    0.014    0.000   13.140    0.008 /usr/lib/python3.12/selectors.py:451(select)
     1628   13.119    0.008   13.119    0.008 {method 'poll' of 'select.epoll' objects}
     1724    0.011    0.000    1.752    0.001 /usr/lib/python3.12/asyncio/events.py:86(_run)
     1726    0.011    0.000    1.741    0.001 {method 'run' of '_contextvars.Context' objects}
     2641    0.015    0.000    1.128    0.000 /usr/lib/python3.12/traceback.py:377(extract)
     2641    0.367    0.000    1.113    0.000 /usr/lib/python3.12/traceback.py:399(_extract_from_extended_frame_gen)
     1460    0.012    0.000    1.071    0.001 /usr/lib/python3.12/asyncio/tasks.py:653(sleep)
      670    0.002    0.000    1.063    0.002 /home/stefan/test/performance_app.py:16(test_type_text)
      666    0.001    0.000    1.050    0.002 /home/stefan/test/.venv/lib/python3.12/site-packages/textual/pilot.py:75(press)
      665    0.003    0.000    1.048    0.002 /home/stefan/test/.venv/lib/python3.12/site-packages/textual/app.py:1636(_press_keys)
      696    0.028    0.000    1.039    0.001 /home/stefan/test/.venv/lib/python3.12/site-packages/textual/_wait.py:8(wait_for_idle)
      931    0.007    0.000    0.751    0.001 /usr/lib/python3.12/traceback.py:221(extract_stack)
      890    0.007    0.000    0.744    0.001 /usr/lib/python3.12/asyncio/base_events.py:447(create_future)
     1711    0.014    0.000    0.421    0.000 /usr/lib/python3.12/asyncio/events.py:36(__init__)
     1710    0.015    0.000    0.402    0.000 /usr/lib/python3.12/asyncio/format_helpers.py:62(extract_stack)
      892    0.007    0.000    0.342    0.000 {method 'set_result' of '_asyncio.Future' objects}
      961    0.009    0.000    0.341    0.000 /usr/lib/python3.12/asyncio/base_events.py:785(call_soon)
      729    0.004    0.000    0.321    0.000 /usr/lib/python3.12/asyncio/futures.py:311(_set_result_unless_cancelled)
    25370    0.055    0.000    0.287    0.000 /usr/lib/python3.12/linecache.py:52(checkcache)
      978    0.010    0.000    0.275    0.000 /usr/lib/python3.12/asyncio/base_events.py:814(_call_soon)
    24953    0.227    0.000    0.228    0.000 {built-in method posix.stat}
      732    0.007    0.000    0.207    0.000 /usr/lib/python3.12/asyncio/base_events.py:743(call_later)
      732    0.008    0.000    0.198    0.000 /usr/lib/python3.12/asyncio/base_events.py:767(call_at)
      106    0.000    0.000    0.181    0.002 /home/stefan/test/.venv/lib/python3.12/site-packages/textual/timer.py:142(_run_timer)
      106    0.004    0.000    0.181    0.002 /home/stefan/test/.venv/lib/python3.12/site-packages/textual/timer.py:149(_run)
      734    0.006    0.000    0.177    0.000 /usr/lib/python3.12/asyncio/events.py:155(cancel)

Textual Diagnostics

Versions

Name	Value
Textual	0.80.1
Rich	13.8.1

Python

Name	Value
Version	3.12.3
Implementation	CPython
Compiler	GCC 13.2.0
Executable	/home/stefan/test/.venv/bin/python

Operating System

Name	Value
System	Linux
Release	6.8.0-45-generic
Version	#45-Ubuntu SMP PREEMPT_DYNAMIC Fri Aug 30 12:02:04 UTC 2024

Terminal

Name	Value
Terminal Application	Unknown
TERM	xterm-256color
COLORTERM	Not set
FORCE_COLOR	Not set
NO_COLOR	Not set

Rich Console options

Name	Value
size	width=221, height=26
legacy_windows	False
min_width	1
max_width	221
is_terminal	True
encoding	utf-8
max_height	26
justify	None
overflow	None
no_wrap	False
highlight	None
markup	None
height	None

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• How do I center a widget in a screen?

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This is an automated reply, generated by FAQtory

[TomJGooding]

I'm not so familiar with unittest, but this test only takes a second to run on my machine just using pytest along with the pytest-asyncio plugin:

from textual.app import App, ComposeResult
from textual.widgets import Input


class PerformanceIssueApp(App):
    def compose(self) -> ComposeResult:
        yield Input()


async def test_type_text() -> None:
    app = PerformanceIssueApp()
    async with app.run_test() as pilot:
        await pilot.press(*"This is my text!")

        input_widget = pilot.app.query_exactly_one(Input)
        assert input_widget.value == "This is my text!"