my $incl_generated_files = shift if @ARGV && $ARGV[0] eq '--gen';
system "git-checkout master" and exit 1;
if ($incl_generated_files) {
die "'a' must not exist in the current directory.\n" if -e 'a';
die "'b' must not exist in the current directory.\n" if -e 'b';
my $incl_generated_files = shift if @ARGV && $ARGV[0] eq '--gen';
system "git-checkout master" and exit 1;
if ($incl_generated_files) {
die "'a' must not exist in the current directory.\n" if -e 'a';
die "'b' must not exist in the current directory.\n" if -e 'b';