Improve testing on native Windows

Modify the testing infrastructure to better work with Git for Windows on
native Windows.  Due to limitations/bugs in the current implementation
of Git.pm, git-svn-diff will not run in this environment.  However, once
those issues are addressed upstream, these changes will make it possible
to validate git-svn-diff.

When it all comes together, users will be able to run git-svn-diff in a
native Windows environment (assuming they have Perl installed somewhere,
with a modern Git.pm).  Batch or PowerShell scripts will be possible;
users can completely avoid Git Bash, if they so desire.

Issue: #39

Author: ColMelvin

t/lib/Temp/Repo.pm

@@ -32,7 +32,13 @@ sub _initialize {
 	my $dir = $self->{dir};
 	__run_in($dir, qw(svnadmin create repo));
 
-	my $repo = "file://@{[File::Spec::Unix->canonpath($dir)]}/repo";
+	my $base = File::Spec::Unix->canonpath($dir);
+	if ($^O eq "MSWin32") {
+		$base =~ s{\\}{/}g;
+		$base = "/$base";
+	}
+
+	my $repo = "file://$base/repo";
 	$self->{repo} = $repo;
 
 	# Setup the standard layout, if requested.
@@ -44,6 +50,7 @@ sub _initialize {
 
 	# Clone SVN & Git repositories.
 	__run_in($dir, qw(svn checkout -q), $repo, "svn");
+	$repo =~ s{^(file:///\w):}{$1} if $^O eq "MSWin32";	# Workaround for https://github.com/git-for-windows/git/issues/1593
 	__run_in($dir, qw(git svn init), @git_opts, $repo, "git");
 }
 
@@ -150,7 +157,7 @@ sub svn_diff {
 
 sub git_svn_diff {
 	my ($self, @args) = @_;
-	my ($out, $err) = __capture_cmd($self->get_git_wc(), $diff_bin, @args);
+	my ($out, $err) = __capture_cmd($self->get_git_wc(), $^X, $diff_bin, @args);
 	warn $err if $err;
 	return $out;
 }
@@ -162,6 +169,7 @@ sub create_git_orderfile {
 
 	my $file = File::Spec->catfile($self->{dir}, "orderfile");
 	open my $fh, '>', $file or die "Cannot open file “$file”: $!";
+	binmode $fh or die "Cannot set binmode: $!";	# Needed for Git on Windows
 	print {$fh} join "\n", @order, '';
 	close $fh or warn "Cannot close file “$file”: $!";
 

t/no-svn-commits.t

@@ -19,31 +19,31 @@ system qw(git commit -m), "Modifications";
 
 write_file("file", "Changed contents\nWorking copy\n");
 
-my $got = qx{"$diff_bin" -c 1 2>&1};
+my $got = qx{"$^X" "$diff_bin" -c 1 2>&1};
 my $expected = <<ERR;
 fatal: Cannot find revision: 1
 ERR
 is($got, $expected, "Revision 1 not found");
 
-$got = qx{"$diff_bin" -c 2 2>&1};
+$got = qx{"$^X" "$diff_bin" -c 2 2>&1};
 $expected = <<ERR;
 fatal: Cannot find revision: 2
 ERR
 is($got, $expected, "Revision 2 not found");
 
-$got = qx{"$diff_bin" HEAD^ HEAD 2>&1};
+$got = qx{"$^X" "$diff_bin" HEAD^ HEAD 2>&1};
 $expected = <<ERR;
 fatal: Commit '[0-9a-f]{40}' must be in SVN repository
 ERR
 like($got, qr/$expected/, "Cannot resolve revision");
 
-$got = qx{"$diff_bin" 2>&1};
+$got = qx{"$^X" "$diff_bin" 2>&1};
 $expected = <<ERR;
 fatal: Cannot find SVN base commit in branch
 ERR
 is($got, $expected, "Cannot resolve revision");
 
-my $got = qx{"$diff_bin" -r 1 2>&1};
+my $got = qx{"$^X" "$diff_bin" -r 1 2>&1};
 my $expected = <<ERR;
 fatal: Cannot find revision: 1
 ERR

t/no-svn-remote.t

@@ -3,6 +3,8 @@
 use FindBin;
 use lib "$FindBin::Bin/lib";
 
+use File::chdir;
+
 use Test::More tests => 2;
 use Test::Repo;
 
@@ -49,7 +51,11 @@ Test::Repo::test_diff($repo, name => "Diff with BASE");
 my $diff_bin = "$FindBin::Bin/../bin/git-svn-diff";
 my $dir = $repo->get_git_wc();
 
-my $got = qx{cd "$dir"; "$diff_bin" --relative-repo 2>&1};
+my $got;
+{
+	local $CWD = $dir;
+	$got = qx{"$^X" "$diff_bin" --relative-repo 2>&1};
+}
 my $expected = <<ERR;
 svn info: command returned error: 1
 ERR