I refactored the unit tests for all the demo programs
to follow a different pattern that makes it simpler
to add more demo tests in the future.
The main thing is that correct output and generated
output are now in separate directories `correct` and `test`.
I have moved the test scripts from `test/test` to `./demotest`
in all the langauge demo directories.
This makes it simpler to clean up any stale generated
files before each test run by `rm -f test/*.txt`.
I stumbled across this while making the Java demo tests,
and it was a better solution, so now all the other languages
are consistent with the Java demo tests.
In the C demo tests, I also decided to compile all the
binary executables into a subdirectory `bin` that can
be cleaned out before each run, to make sure there are
no stale executables from an earlier run.
For years before 1582 or years after 3668, the Seasons functions
were unable to find many equinoxes and/or solstices.
The problem was that over time, the Earth's axis precesses
enough that the calendar dates of these events drifts outside
the fixed search ranges I had provided for them.
I expanded the search ranges so all season changes can be found
for a much wider range of years, as verified by unit tests:
C/C++: -2000..9999
C#: 1..9999
JavaScript: -2000..9999
Python: 1..9999
Kotlin: 1..9999
Note: C#, Python, and Kotlin currently do not allow
years values below +1. In fact, I discovered we were not
noticing when an invalid year was passed into the Kotlin code.
I updated that code to throw an exception when the year does
not match what was expected. It is disturbing that the
GregorianCalendar class silently ignores invalid years!
Constricted the search tolerance from 1 second to 0.01
seconds for the seasons search, to ensure more consistent
behavior.
Fixed a bug in the Kotlin search() function's
quadratic interpolation that was causing the convergence
to be slower than it should have been.
I'm getting much better accuracy sticking with my original
gravity simulator, just with smaller time increments, than
I was with the Runge-Kutta 4 method. The PlutoStateTable
gets a bit larger (51 state vectors instead of 41), but the
accuracy is so much higher.
Removed the Runge-Kutta code because I won't be going back to it.
The calendar enumerator demo now includes inferior and superior
conjunctions of the inner planets (Mercury and Venus), along
with the conjunctions and oppositions of the outer planets
(Mars ... Pluto).
Added MoonQuarterEnumerator, which finds new moon, first quarter,
full moon, and third quarter events.
Changed the calendar start date to May 2021, so it is
more relevant to the time I'm testing it.
This is an example of how multiple enumerators can be combined
into an EventCollator. The collator does the minimum amount
of work to keep searching for one event at a time, while always
emitting them in chronological order.
