[O] FYI: with-org-today-date macro, helps with testing

[Adam Porter]

Hi friends,

Just wanted to drop this here.  I was testing some agenda-related code,
and got tired of having to keep moving the dates forward on my test data
as days passed in real life, so after digging into the agenda code, I
came up with this macro that makes testing much easier:

#+BEGIN_SRC elisp
  (defmacro with-org-today-date (date &rest body)
    "Run BODY with the `org-today' function set to return simply DATE.
  DATE should be a date-time string (both date and time must be included)."
    (declare (indent defun))
    `(let ((day (date-to-day ,date))
           (orig (symbol-function 'org-today)))
       (unwind-protect
           (progn
             (fset 'org-today (lambda () day))
             ,@body)
         (fset 'org-today orig))))
#+END_SRC

You can use it like this:

#+BEGIN_SRC elisp
  (with-org-today-date "2017-07-05 00:00"
    (let ((org-agenda-files (list "~/test.org"))
          (org-agenda-span 'day))
      (org-agenda-list nil)))
#+END_SRC

Hope someone finds this useful.