Unit Tests

- Added tests for blank values from missing DOM lookups.

test/dom.2.t

@@ -27,7 +27,7 @@
 
 use strict;
 use warnings;
-use Test::More tests => 4;
+use Test::More tests => 5;
 
 # Ensure environment has no influence.
 delete $ENV{'TASKDATA'};
@@ -60,6 +60,10 @@ my $uuid = chomp $output;
 $output = qx{../src/task rc:dom.rc _get ${uuid}.id 2>&1};
 like ($output, qr/^1$/, 'DOM uuid --> id');
 
+# Failed DOM lookup returns blank.
+$output = qx{../src/task rc:dom.rc _get 4.description 2>&1};
+like ($output, qr/^$/, "DOM 4.description --> ''");
+
 # Cleanup.
 unlink qw(pending.data completed.data undo.data backlog.data dom.rc);
 exit 0;