test/: Add generic tests for todo operations

* todo-001.sh: Tests the "-t" command line option (calculates expected
  output by parsing the todo data file).

* todo-002.sh: Tests "-t<num>" in a way similar to todo-001.sh.

* todo-003.sh: Tests "-t0" in a way similar to todo-001.sh.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

test/todo-003.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+if [ "$1" = 'actual' ]; then
+  calcurse -D data/ -t0 | sort -n
+elif [ "$1" = 'expected' ]; then
+  (
+    echo 'completed tasks:'
+    sed -n 's/^\[-\([0-9]\)\] \(.*\)/\1. \2/p' data/todo
+  ) | sort -n
+else
+  ./run-test "$0"
+fi