test_datetime_format
====================

.. py:module:: test_datetime_format

.. autoapi-nested-parse::

   The datetime formatter's golden, and the constants the tile divides by.

   The tile has no divider: every division in it is a multiply-shift by a
   compile-time constant, and a multiply-shift identity is only valid over a
   bounded input range. Those bounds are the whole correctness argument for the
   arithmetic, and they live in the HDL as bare magic numbers -- so this reads
   them back out of the .sv and proves each one against real floor division at
   BOTH ENDS of every quotient block, which is where such an identity fails
   first. A constant edited in the HDL without its range being re-derived fails
   here rather than in a rendered date.



Attributes
----------

.. autoapisummary::

   test_datetime_format.EPOCH
   test_datetime_format.MULTIPLY_SHIFT_SITES


Functions
---------

.. autoapisummary::

   test_datetime_format._hdl_constants
   test_datetime_format.test_the_tiles_multiply_shift_constants_are_exact_over_their_declared_range
   test_datetime_format.test_the_golden_agrees_with_the_standard_library_at_the_boundaries
   test_datetime_format.test_the_golden_agrees_with_the_standard_library_over_a_random_sweep
   test_datetime_format.test_every_day_of_one_leap_year_and_one_common_year_renders
   test_datetime_format.test_out_of_range_epochs_have_no_rendering


Module Contents
---------------

.. py:data:: EPOCH

.. py:data:: MULTIPLY_SHIFT_SITES

.. py:function:: _hdl_constants() -> dict[str, int]

.. py:function:: test_the_tiles_multiply_shift_constants_are_exact_over_their_declared_range(site: str, pre_shift: int, divisor: int, max_input: int) -> None

.. py:function:: test_the_golden_agrees_with_the_standard_library_at_the_boundaries() -> None

.. py:function:: test_the_golden_agrees_with_the_standard_library_over_a_random_sweep() -> None

.. py:function:: test_every_day_of_one_leap_year_and_one_common_year_renders() -> None

   Leap handling is not special-cased anywhere -- it falls out of the
   400-year era arithmetic -- so the way to check it is to walk the days.


.. py:function:: test_out_of_range_epochs_have_no_rendering() -> None