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/Makefile.am

@@ -3,7 +3,10 @@ AUTOMAKE_OPTIONS = foreign
 TESTS = \
 	true-001.sh \
 	run-test-001.sh \
-	run-test-002.sh
+	run-test-002.sh \
+	todo-001.sh \
+	todo-002.sh \
+	todo-003.sh
 
 check_PROGRAMS = run-test
 check_SCRIPTS = $(TESTS)