$line = sprintf qq{Test #1 'Show me Waynes world','Jennys Basketball shoes'\n};
print $line;   # <- added this line
$line =~ s/(')[^'\\]*(?:\\.[^'\\]*)*(')/$1SSS$2/g;
print $line;

$line = sprintf qq{Test #2 'Show me Wayne\\'s world','Jenny\\'s Basketball shoes'\n};  # <- changed this line (two extra \ added)
print $line;   # <- added this line
$line =~ s/(')[^'\\]*(?:\\.[^'\\]*)*(')/$1SSS$2/g;
print $line;