Removed stable id check in loop. Added comments

modules/t/gene.t

@@ -474,15 +474,18 @@ cmp_ok($new_gene->start(), '==', 30735607, 'Updated gene start');
 cmp_ok($new_gene->end(), '==', 30815178, 'Updated gene end');
 
 # test update_coords method when working on sub Slice
-my $update_slice = $db->get_SliceAdaptor()->fetch_by_region('chromosome', '20', 30730000, 30815178);
+# to avoid setting the start and end relative to a sub Slice
+# correct coords: 30735607 - 30815178
+# wrong coords: 1 - 79572
+my $update_slice = $db->get_SliceAdaptor()->fetch_by_gene_stable_id('ENSG00000171456');
+# Make sure that the slice of the gene is a sub Slice
 my $update_genes = $update_slice->get_all_Genes();
-cmp_ok(scalar(@$update_genes), '>=', 1, 'Check the region has at least one gene');
+# Update the coordinates of the gene in the database
 foreach my $gene_to_update (@$update_genes) {
-  if ($gene_to_update->stable_id() eq 'ENSG00000171456') {
-    $ga->update_coords($gene_to_update);
-  }
+  $ga->update_coords($gene_to_update);
 }
 
+# Fetch the gene again to check the coordinates
 my $updated_gene = $ga->fetch_by_stable_id("ENSG00000171456");
 cmp_ok($updated_gene->start(), '==', 30735607, 'Updated gene start');
 cmp_ok($updated_gene->end(), '==', 30815178, 'Updated gene end');