In the PR #25 Windows CI support is in progress.
I describe here some changes needed for windows support.

CLI options

Windows has expanded console support in recent years, with multiple implementations coexisting.
To make these choices, I decided to use the CLI option.
As an example, the following is a way to specify that conhost is used, the window under test is displayed, and the failed test is not closed but left in place.
rake TESTOPTS="--windows=conhost --show-console --close-console=pass"
Additional options are follows.

yamatanooroti options
        --wait=0.01                  Specify yamatanooroti wait time in seconds.
        --timeout=2.0                Specify yamatanooroti timeout in seconds.
windows specific yamatanooroti options
        --windows=TYPE               Specify console type
                                     (ca[nary], co[nhost], l[egacy-conhost], p[review], s[table])
                                     (1.17, 1.18, 1.19, 1.20, 1.21, 1.21preview, 1.22preview)
        --wt-dir=DIR                 Specify Windows Terminal working dir.
                                     Automatically determined if not specified and treated temporary.
                                     DIR is treaded permanent if specified and download files are remains.
        --[no-]show-console          Show test ongoing console.
        --[no-]close-console[=COND]  Close test target console when COND met
                                     (a[lways], n[ever], p[ass])

Yamatanooroti API changes

The behavior of Windows conhost (aka. Command Prompt Window) changes depending on the code page settings.
Needed to support code page changes to correctly display DBCS in a CI environment.
To change the codepage before launch of the target process, the codepage must be specified in start_terminal().
Currently, it is treated as windows specific and the new settings are used only in a windows environment.
‘‘‘
def setup
if Yamatanooroti.win?
start_terminal(5, 30, ['ruby', 'bin/simple_repl'], startup_message: 'prompt>', codepage: 932)
else
start_terminal(5, 30, ['ruby', 'bin/simple_repl'], startup_message: 'prompt>')
end
end
‘‘‘
Since Yamatanooroti.win is included in the existing yamatanooroti, the changes will not affect non-Windows environments.
However, since the test code appears to be redundant, it is also a consideration to modify the vterm side to accept it as **kwargs and ignore it.

Another changes

A test-unit specific api is used to reduce signal handler invalidation by the WIN32API used and to determine window close by test results. For example, Test::Unit.at_exit testdown do; end
Since yamatanooroti is not executed in the ruby test, I have determined that this does not affect it, but I have not confirmed this.