Test Python demos in Windows also.

Before now, the Python demos were tested in Linux and Mac.
Now they are tested in the Windows environment also.
This will be helpful for any contributors who may wish
to use Windows as a development platform for the Python
version of Astronomy Engine.

demo/python/demotest.bat

@@ -0,0 +1,67 @@
+@echo off
+setlocal EnableDelayedExpansion
+
+if not exist test (md test)
+if exist test\*.txt (del test\*.txt)
+
+call :TestDemo solar_time +38.88 -77.03 2023-02-12T17:00:00Z || exit /b 1
+call :TestDemo jupiter_moons 2021-04-16T00:26:18Z || exit /b 1
+call :TestDemo constellation 2021-06-01T00:00:00Z || exit /b 1
+call :TestDemo moonphase 2019-06-15T09:15:32.987Z || exit /b 1
+call :TestDemo riseset +45.6 -90.7 2018-11-30T17:55:07.234Z || exit /b 1
+call :TestDemo positions +45.6 -90.7 2018-11-30T17:55:07.234Z || exit /b 1
+call :TestDemo seasons 2019 || exit /b 1
+call :TestDemo culminate +30 -90 2015-02-28T00:00:00Z || exit /b 1
+call :TestDemo horizon +25.5 -85.3 2016-12-25T12:30:45Z || exit /b 1
+call :TestDemo lunar_eclipse 1988-01-01 || exit /b 1
+call :TestDemo lunar_angles 2021-05-15 || exit /b 1
+call :TestDemo galactic 38.92056 -77.0658 22.793498 197.070510 2025-04-06T00:00:00Z || exit /b 1
+call :TestDemo triangulate 48.16042 24.49986 2019 18 7 48.27305 24.36401 662 83 12 || exit /b 1
+call :TestDemo stars_near_moon 30 -80 2021-11-08T23:00:00Z || exit /b 1
+call :TestDemo ecliptic_of_date 53.6375 9.9981 2023-10-28T20:24:33.489Z || exit /b 1
+call :TestDemo solar_eclipse 28.5 -82.5 2023-01-01 || exit /b 1
+
+call :CameraTest _nz -41.17 175.5 2023-03-24T06:30:00Z || exit /b 1
+call :CameraTest _fl +29 -81 2023-03-25T00:00:00Z || exit /b 1
+call :CameraTest _ca 51.05 -114.07 2023-03-24T02:07:31.000Z || exit /b 1
+
+echo.Testing Python demo: gravity
+for /L %%x in (0, 1, 90) do (
+    py gravity.py %%x 0 >> test/gravity.txt || Fail "Error running gravity.py."
+)
+fc correct\gravity.txt test\gravity.txt || exit /b 1
+echo.PASS: Python demos
+exit /b 0
+
+
+:TestDemo
+    set name=%1
+    set args=%2 %3 %4 %5 %6 %7 %8 %9
+    REM *** Hack to handle more than 8 arguments needed by triangulate.py
+    shift
+    set args=!args! %9
+    shift
+    set args=!args! %9
+    echo.Testing Python demo: !name! !args!
+    mypy --strict !name!.py || exit /b 1
+    echo.Running !name!.py !args!
+    py !name!.py !args! > test\!name!.txt || (
+        echo.FATAL[demotest.bat] - error returned by !name!.py
+        exit /b 1
+    )
+    fc correct\!name!.txt test\!name!.txt || exit /b 1
+    exit /b 0
+
+:CameraTest
+    set name=camera
+    set suffix=%1
+    set args=%2 %3 %4 %5 %6 %7 %8 %9
+    echo.Testing Python demo: !name! !args!
+    mypy --strict !name!.py || exit /b 1
+    echo.Running !name!.py !args!
+    py !name!.py !args! > test\!name!!suffix!.txt || (
+        echo.FATAL[demotest.bat] - error returned by !name!.py
+        exit /b 1
+    )
+    fc correct\!name!!suffix!.txt test\!name!!suffix!.txt || exit /b 1
+    exit /b 0

generate/run.bat

@@ -212,6 +212,13 @@ call diffcalc.bat || exit /b 1
 
 REM -----------------------------------------------------------------------------------------
 
+echo.Validating Python demos.
+pushd ..\demo\python
+call demotest.bat || exit /b 1
+popd
+
+REM -----------------------------------------------------------------------------------------
+
 echo.Validating Java demos.
 pushd ..\demo\java
 call demotest.bat || exit /b 1