\input regression-test.tex
\documentclass{article}
\usepackage{kanban-board}
\begin{document}
\sbox0{\scriptsize $x$}% Load math font sizes outside captured output.
\START
\makeatletter
\newcommand\kbexpectdisplay[4]{%
  \def\kanban@boarddateformat{#1}%
  \kanban@preparedeadline{#2}%
  \ifdefstring{\kb@displaydeadline}{#3}
    {\TYPE{#4 OK}}
    {\TYPE{#4 FAILED: \kb@displaydeadline}}}
\newcommand\kbexpectdatealias[3]{%
  \kanban@canonicaldateformat{#1}%
  \ifdefstring{\kb@datechoice}{#2}
    {\TYPE{#3 OK}}
    {\TYPE{#3 FAILED}}}
\ifdefstring{\kanban@dateformat}{us}
  {\TYPE{KANBAN DEFAULT DATE FORMAT US OK}}
  {\TYPE{KANBAN DEFAULT DATE FORMAT US FAILED}}
\kbexpectdisplay{us}{18.07.2026}{07/18/2026}
  {KANBAN US DISPLAY}
\kbexpectdisplay{english}{2026-07-18}{18/07/2026}
  {KANBAN ENGLISH DISPLAY}
\kbexpectdisplay{german}{2026/07/18}{18.07.2026}
  {KANBAN GERMAN DISPLAY}
\kbexpectdisplay{iso}{07/18/2026}{2026-07-18}
  {KANBAN ISO DISPLAY}
\kbexpectdisplay{ymd}{18/07/2026}{2026/07/18}
  {KANBAN YMD DISPLAY}
\kbexpectdisplay{iso}{2026-7-8}{2026-07-08}
  {KANBAN LOOSE ISO DISPLAY}
\kbexpectdisplay{us}{2026/7/8}{07/08/2026}
  {KANBAN LOOSE YEAR-FIRST DISPLAY}
\kbexpectdisplay{german}{7/8/2026}{07.08.2026}
  {KANBAN LOOSE SLASH DISPLAY}
\kbexpectdisplay{us}{18.07.26}{18.07.26}
  {KANBAN TWO-DIGIT YEAR UNCHANGED}
\kbexpectdisplay{us}{M2}{M2}
  {KANBAN PROJECT MONTH UNCHANGED}
\kbexpectdisplay{us}{M01}{M01}
  {KANBAN LEADING ZERO PROJECT MONTH UNCHANGED}
\kbexpectdisplay{us}{Editorial review}{Editorial review}
  {KANBAN DESCRIPTIVE LABEL UNCHANGED}
\kbexpectdatealias{american}{us}{KANBAN AMERICAN DATE ALIAS}
\kbexpectdatealias{uk}{english}{KANBAN UK DATE ALIAS}
\kbexpectdatealias{ BrItIsH }{english}{KANBAN BRITISH DATE ALIAS}
\kbexpectdatealias{de}{german}{KANBAN DE DATE ALIAS}
\kbexpectdatealias{deutsch}{german}{KANBAN DEUTSCH DATE ALIAS}
\kbexpectdatealias{year-first}{ymd}{KANBAN YEAR-FIRST DATE ALIAS}
\ExplSyntaxOn
\cs_new_protected:Npn \kb_expect_components:nnnnn #1#2#3#4#5
  {
    \__kanban_parse_date:nn {#1} {#2}
    \bool_if:nTF
      {
        \l__kanban_valid_date_bool
        && \int_compare_p:nNn {\l__kanban_deadline_year_int} = {#3}
        && \int_compare_p:nNn {\l__kanban_deadline_month_int} = {#4}
        && \int_compare_p:nNn {\l__kanban_deadline_day_int} = {#5}
      }
      {\TYPE{KANBAN~#2~SLASH~PARSE~#1~OK}}
      {\TYPE{KANBAN~#2~SLASH~PARSE~#1~FAILED}}
  }
\kb_expect_components:nnnnn {07/08/2026}{us}{2026}{7}{8}
\kb_expect_components:nnnnn {07/08/2026}{english}{2026}{8}{7}
\kb_expect_components:nnnnn {07/08/2026}{german}{2026}{8}{7}
\kb_expect_components:nnnnn {31/07/2026}{us}{2026}{7}{31}
\kb_expect_components:nnnnn {07/31/2026}{english}{2026}{7}{31}
\kb_expect_components:nnnnn {2026-7-8}{us}{2026}{7}{8}
\ExplSyntaxOff
\kbset{date-format=german}
\ifdefstring{\kanban@dateformat}{german}
  {\TYPE{KANBAN SETUP DATE FORMAT OK}}
  {\TYPE{KANBAN SETUP DATE FORMAT FAILED}}
\begin{kanban}[columns={Todo},date-format=english]
  \ifdefstring{\kanban@boarddateformat}{english}
    {\TYPE{KANBAN BOARD DATE FORMAT OVERRIDE OK}}
    {\TYPE{KANBAN BOARD DATE FORMAT OVERRIDE FAILED}}
  \kanbantask[due=2026-07-18]{Todo}{Test local formatting}
\end{kanban}
\ifdefstring{\kanban@dateformat}{german}
  {\TYPE{KANBAN BOARD DATE FORMAT SCOPE OK}}
  {\TYPE{KANBAN BOARD DATE FORMAT SCOPE FAILED}}
\begingroup
  % Capture the named message semantically. The console rendering of
  % l3msg varies across TeX Live releases.
  \ExplSyntaxOn
  \cs_set_protected:Npn \msg_warning:nnnn #1#2#3#4
    {\TYPE{KANBAN~WARNING:~#2~#3~'#4'}}
  \ExplSyntaxOff
  \kbset{date-format=martian}
  \ifdefstring{\kanban@dateformat}{german}
    {\TYPE{KANBAN INVALID DATE FORMAT PRESERVES VALUE OK}}
    {\TYPE{KANBAN INVALID DATE FORMAT PRESERVES VALUE FAILED}}
  \begin{kanban}[columns={Todo},date-format=martian]
    \ifdefstring{\kanban@boarddateformat}{german}
      {\TYPE{KANBAN INVALID BOARD DATE FORMAT PRESERVES VALUE OK}}
      {\TYPE{KANBAN INVALID BOARD DATE FORMAT PRESERVES VALUE FAILED}}
    \kanbantask{Todo}{Exercise board date format validation}
  \end{kanban}
\endgroup
\makeatother
\END
\end{document}