use strict;
use warnings;
use Test::More  tests => 5;
my %ENV = (     # Overrides the global for this test
    playground => 'myplay',
    HOME       => 'myhome',
    le1        => 'fix_for_file1'
);
my @expected = (
    q(set playground="myhome/playground")."\n",
    q(set file1=myplay'/fifix_for_file1')."\n",
    q(set file2=myplay'/file2$')."\n",
    q(set file3=myplay'/f$i$l$e$3$')."\n",
    q(set file4=myplay'/fi\$le4')."\n",

);
#                        look
#                        behind  |------ $1 ------|
my $with_braces    = qr/ (?<!\\) ( \$ \{ (\w+) \} ) /x;
my $without_braces = qr/ (?<!\\) ( \$    (\w+)    ) /x;
#                                        |$2 |


while (<DATA>) {
    s!$with_braces   !$ENV{$2}//$1!xge;
    s!$without_braces!$ENV{$2}//$1!xge;
    is( $_ , shift @expected, $_ ); 
}
__DATA__
set playground="${HOME}/playground"
set file1=${playground}'/fi$le1'
set file2=${playground}'/file2$'
set file3=${playground}'/f$i$l$e$3$'
set file4=${playground}'/fi\$le4'

##</code><code>##

1..5
ok 1 - set playground="myhome/playground"
#
ok 2 - set file1=myplay'/fifix_for_file1'
#
ok 3 - set file2=myplay'/file2$'
#
ok 4 - set file3=myplay'/f$i$l$e$3$'
#
ok 5 - set file4=myplay'/fi\$le4'
#