Fix unix domain socket tests on Windows

perl/MANIFEST

@@ -14,4 +14,5 @@ MANIFEST.SKIP
 README
 t/01-load.t
 t/02-unix_domain_socket.t
+t/03-network_socket.t
 typemap

perl/t/02-unix_domain_socket.t

@@ -28,15 +28,7 @@ if ($ENV{PERL_CORE} and $Config{'extensions'} !~ /\bSocket\b/) {
 } elsif (! $can_fork) {
     plan skip_all => 'no fork';
 } elsif ($^O eq 'MSWin32') {
-    if ($ENV{CONTINUOUS_INTEGRATION}) {
-        # https://github.com/Perl/perl5/issues/17429
-        plan skip_all => 'Skipping on Windows CI';
-    } else {
-        # https://github.com/Perl/perl5/issues/17575
-        if (! eval { socket(my $sock, PF_UNIX, SOCK_STREAM, 0) }) {
-            plan skip_all => "AF_UNIX unavailable or disabled on this platform"
-        }
-    }
+    plan skip_all => "FCGI with UNIX domain sockets not implemented on $^O";
 }
 
 my (undef, $unix_socket_file) = tempfile();

perl/t/03-network_socket.t

@@ -0,0 +1,59 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+use FCGI;
+use FCGI::Client;
+use IO::Socket::IP;
+use Test::More 'tests' => 4;
+
+my $port = 8888;
+
+# Client
+if (my $pid = fork()) {
+    my $right_ret = <<'END';
+Content-Type: text/plain
+
+END
+
+    my ($stdout, $stderr) = client_request($port);
+    is($stdout, $right_ret."0\n", 'Test first round on stdout.');
+    is($stderr, undef, 'Test first round on stderr.');
+
+    ($stdout, $stderr) = client_request($port);
+    is($stdout, $right_ret."1\n", 'Test second round on stdout.');
+    is($stderr, undef, 'Test second round on stderr.');
+
+# Server
+} elsif (defined $pid) {
+    my $fcgi_socket = FCGI::OpenSocket(':'.$port, 5);
+    my $request = FCGI::Request(\*STDIN, \*STDOUT, \*STDERR, \%ENV, $fcgi_socket);
+
+    # Only two cycles.
+    my $count = 0;
+    while ($count < 2 && $request->Accept() >= 0) {
+        print "Content-Type: text/plain\n\n";
+        print $count++."\n";
+    }
+    exit;
+
+} else {
+    die $!;
+}
+
+sub client_request {
+    my $port = shift;
+
+    my $sock = IO::Socket::IP->new(
+        PeerAddr => '127.0.0.1',
+        PeerPort => $port,
+    ) or die $!;
+
+    my $client = FCGI::Client::Connection->new(sock => $sock);
+    my ($stdout, $stderr) = $client->request({
+        REQUEST_METHOD => 'GET',
+    }, '');
+
+    return ($stdout, $stderr);
+}