#!/usr/bin/env perl
use strict;
use warnings;
use File::Slurp::Tiny 'read_file';

my $file  = 'contig.txt';
my $slurp = read_file($file);
my %results;

while ( $slurp =~ />Contig(\d+).+?([A-Z]+)/sg ) {
  $results{ $1 } = $2;
}

foreach my $test_number (sort keys %results ) {
  print "Test $test_number: $results{ $test_number }\n\n";
  ## do something to process $test_number, $results{ $test_number } ...
}

__END__

OUTPUT:

Test 1: GAGCTAAATAATTTGAATCAATGGGAAGATCACCGTGTTGTGAAAAAGCACATACAAATAAAGGAGCTTGGACTAAAGAAGAAGATGAACGACTTATTTCTTATATTAAAACTCACGGCGAAGGTTGCTGGAGATCCCTTCCTAAAGCTGCCGGACTTCTCCGATGCGGTAAAAGTTGCCGTCTCCGATGGATTAATTACTTGAGACCGGACCTTAAACGCGGTAATTTTACTGAAGAAGAAGATGAACTCATTATCAAACTCCATAGCCTCCTTGGTAACAAATGGTCACTTATAGCCGGAAGATTACCAGGAAGAACAGATAATGAGATAAAAAATTACTGGAATACGCACATAAGAAGGAAGCTTTTGAGTCGGGGCATTGATCCAACGACACACAGGCCTGTTAACGAGCCTGGTACAACGCAAAAAGTCACAACAATTTCATTTGCAGGTGGAGATCATAAAACTAAAGATATTGAAGAAGATCATAATAAGATGATAAATGTCAAAGCTGAATCTGGGTTGAGTCAATTAGAAGATGAAATTATTAGTAGCAGTCCATTTCGAGAACAGTGTCCTGATTTAAATCTTGAGCTCAAATTAGCCCTCCTTCTCTACAAAATTACCAACATAGCCCCTCAAGGTGTTTTGCATGCAGTTTGGGTATACAAAATAGTAAAGATTGCAATTGCAGTAAAAATAATATTGCAAGTTATAACTTTTTAGGATTAAAGAGTAATGGTGTTTTGGACTATAGAACTTTAGAAACTAAGTGAATTTTTATTATAAATCTTTTTTTCCCTCGTGTATTTGGGTTAAAAAAACAAGAAGAGAGAATCGAGAAAGATATTCCTATTAGTTTAAGTTCTTTCGAATTTTCTCTTATTTGTAAAATTTCAAGTATTACTATATACGATATATTATATTAAGTTGAAAAG

Test 2: GCTCTTCCAACAACAACAACAATGCCTCATCAAAAGCCTCTTTCTCTCATTCTTCTATCTACACTCCCACTTCTTTTCATTCTCACACAAGCTCAATCACCAACAGCACCAGCACCAGCACCCTCAGGACCAATAGACATCTTTGCAATCCTCAAAAAAGAAGGACAATACAACACATTCATCAAGTTCCTAAATGAATCACAAGTTGGTAACCAAATCAACAACCAAGTAAACAACTCCAACCAAGGCATGACAGTTTTGGCACCATCAGACAATGCATTTAACAACCTCCCAAGTGGTACACTCAACCAACTAAATGACCAACAAAAAGTACAACTCATTTTGAACCATGTCATACCAAAGTTCTACACATTTGATGACTTACAAACAGTAAGCAACCCTGTTAGAACACAAGCAACAGGGCCTAAAGGTGAGCCTTTTGGACTTAACTTTACTGGAAGTAACAATCAAGTGAATGTCTCATCTGGTTCTGTTGTTACAAACATTTATAATGCTATTAGAAAAGACCCCCCATTGGCTGTTTTTCAATTAGACAAAGTTTTAGTACCTTCTCAGTTTACTGATCCATCTAGTGATGATGATGCCCCTGCACCTACTAAACCCAAGAATGGTACTAGTAATGATAAAACAACAGCTGATGAGCCATCACCAGCAAGTAACACTAAGCCAAATGATGCTAAAAGGATCAGTGGTGGGATTCTTGGATTGGTTTGTGGTGTTTTCTTGATGGCAACACTATCTTGAAGGGGGCTACAGAGTTGTTAACTTTATGATCTTTTGCTTATACTAAGCCATTTTGTATTACATTGTTTTCTTCAAGATTGATTGTTTTTGTTCAAAAAAGAAGGGGGGGGGGGAAAAAAAAACCCCCCTGCGGAAAAGAGCGGGGAAAGCACCAAAAAGCCACCGACCAAAAGCACCAACTCACAAAAGGTGCGCAGACGCGGAAAGGGGAAAAGGAAAAAATGTGAAAGCTTGTTATAGTTTG

Test 3: AAACTGTAATTAGACTTCTCTGCTAAGTTTCTGCTGTATTTGGATTCTCCGGCGAACATTAATATCTAACCATGACCGGCGGTGGAGGCGATGCCGCATCGCCGCCTCTATCCTCACAGTCAACTCCATCCAACGGTGGGGAATTCCTTCTTCAATTGCTTCAGAATCATCCGCATCAACTTCACTCTCAGCCTCAACCGCCACTGCGGCCGGAGTTGCAGAATCTGCCGCATGATCCAGCAGTTGCAGCAGTAGGTCCTAGTATGCCCTACCCGCCATTGTTCCATACTCCTACAAACCCTTCTGTTTTGCCCTATTCTCACTCTCCTCCTCTGTTTGTACCTCATAACTTCTTCATTCGAGGGTTTCTCCAAAACCCTAATTCTGGCCATACCACTAACCCCAATTACTCATCTCCGCCTGCCCCAAGTGGGTTCAGTCAATATCACCATGCGAGTCCACTTGGATTTGGATCAGTCGGAGAAAACATGGGCAATTTGGGGATTTTCGGTGCCAATGCTAAGGCGAG

Test 4: CATGTAATAGCATAGCATCCCCAATTTCACCCTCTCATGGCCATGTCCACGCTCCTCTCCCTGTCCGTGTCTATCCACCCACCAAAACCTTTGCAAAAACCCAATTCAATGTGTACCCAACCTAACTCTATTTCGAGAAGACAAGTGTTTTTCACTGGTTCTAATTTATTGCTCTCTCAATTAATTCCAAAATCCGACGCCCAAACCAATTCCAATAGTTTTCTTTCAGGTATTGCCAATACTAAGTCTTGGTTCCAATTCTATGGCGACGGCTTTTCTATTCGTGTTCCACCGGAATTTCAGGACCTCACTGAGCCGGAGGATTATAATGCTGGCCTATCACTATATGGAGATAAGGCTAAGCCCAAAAAATTTGCAGCACGTTTTGCTTCTTCTGATGGATCCGAAGTTTTAAGTGTCATAATTCGTCCATCCAATCAGCTGAAGATCACTTTCTTAGAGGCTAAAGATATTACTGATTTAGGTTCACTTAAGGAGGCAGCAAAAATATTTGTTCCAGCTGGCTCAACACTATATTCTGTCCGCACAATAAAAATTAAAGAAGATGAGGGTTTCAGGACATACTATTTTTATGAATTTGTGAGAAATGAGCAACACGTTGCATTAGTGGCTGGTGTTAACAGTGGAAAGGCCGTCATTGCTGGTGCCACGGCCCCCGAAAGCAAATGGGCCGAGGATGGTTTGAAGCTCCGATCTGCTGCAGTATCAATGACAATTCTATAAGCAGAATGTGAGTATATATATAGGTTCTATTTCAATGATGATGAATTTATATACAAATATTGAGGATCAAAGTTTTCTTATTATCATCTAATCTCAGCCAAGGATTAACAAT
CTCCATCATCCATTCAATAGCAATGTTTCTGCTGTTTTGC