feat(wpcarro/emacs): Package al, list, set, struct

Originally I set-out to package `al.el`, but as I started traversing the
dependencies, I needed to package increasingly more packages. I refactored some
of these to prune their dependencies to slay this hydra before it turned into a
never-ending project. I have mixed feelings about this.

I also introduced `ert` and unit tests into my Elisp packaging, so it'll be nice
to have build-time tests that run when Emacs updates land in depot.

Change-Id: I2756dc60888b80255a495e08ae61bd547e6b3db2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5998
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI

users/wpcarro/emacs/pkgs/list/tests.el

@@ -0,0 +1,32 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Dependencies
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(require 'ert)
+(require 'list)
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Tests
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(ert-deftest list-length ()
+  (= 0 (list-length '()))
+  (= 5 (list-length '(1 2 3 4 5))))
+
+(ert-deftest list-reduce ()
+  (= 16 (list-reduce 1 (lambda (x acc) (+ x acc)) '(1 2 3 4 5))))
+
+(ert-deftest list-map ()
+  (equal '(2 4 6 8 10)
+         (list-map (lambda (x) (* x 2)) '(1 2 3 4 5))))
+
+(ert-deftest list-xs-distinct-by? ()
+  (list-xs-distinct-by?
+   (lambda (x) (plist-get x :kbd))
+     '((:kbd "C-a" [:name] "foo")
+
+       (:kbd "C-b" :name "[]foo"))))
+
+(ert-deftest list-dedupe-adjacent ()
+  (equal '(1 2 3 4 3 5)
+         (list-dedupe-adjacent '(1 1 1 2 2 3 4 4 3 5 5))))