Unit Tests

- All tests (I hope) now properly remove completed.data on exit, which
  should prevent certain non-deterministic tinderbox results caused by
  residual data.

src/tests/datesort.t

@@ -28,7 +28,7 @@
 
 use strict;
 use warnings;
-use Test::More tests => 6;
+use Test::More tests => 7;
 
 # Create the rc file.
 if (open my $fh, '>', 'datesort.rc')
@@ -60,6 +60,9 @@ like ($output, qr/three.+two.+one/ms, 'Sorting by due- with format MD works');
 unlink 'pending.data';
 ok (!-r 'pending.data', 'Removed pending.data');
 
+unlink 'completed.data';
+ok (!-r 'completed.data', 'Removed completed.data');
+
 unlink 'undo.data';
 ok (!-r 'undo.data', 'Removed undo.data');