Create a unit test system

Setup cantedraw/tests with a test-system record, as well as linking it
back to cantedraw so we can run test-system on cantedraw and run the
tests.

Using parachute, we can setup a suite of unit tests for each package.
For each package in src/ or lib/ we'll write a separate unit test
suite with tests for all the public exposing functionality.

I've setup a main suite in cantedraw/tests/main which will depend on
each of the unit test suites so we can run the tests all at once.

Currently we have one test for the --> macro.

tests/macros.lisp

@@ -0,0 +1,29 @@
+;;; main.lisp - 2025-02-16
+
+;; Copyright (C) 2025 Aryadev Chavali
+
+;; This program is distributed in the hope that it will be useful, but WITHOUT
+;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+;; FOR A PARTICULAR PURPOSE.  See the GNU General Public License Version 2 for
+;; details.
+
+;; You may distribute and modify this code under the terms of the GNU General
+;; Public License Version 2, which you should have received a copy of along with
+;; this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(defpackage cantedraw/tests/macros
+  (:use :cl :cantedraw.lib.macros
+        :parachute))
+
+(in-package :cantedraw/tests/macros)
+
+(define-test macro-test)
+
+(define-test (macro-test "-->")
+  (true (null          (--> x)))
+  (is eq 'a            (--> x 'a))
+  (is eq 2             (--> x 1 (1+ x)))
+  (is eq 2             (--> x 1 1+))
+  (is string= "World!" (--> _ "Hello" (format nil "~a World!" _) (subseq _ 6))))

tests/main.lisp

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+;;; main.lisp - 2025-02-20
+
+;; Copyright (C) 2025 Aryadev Chavali
+
+;; This program is distributed in the hope that it will be useful, but WITHOUT
+;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+;; FOR A PARTICULAR PURPOSE.  See the GNU General Public License Version 2 for
+;; details.
+
+;; You may distribute and modify this code under the terms of the GNU General
+;; Public License Version 2, which you should have received a copy of along with
+;; this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+
+;;; Code:
+
+(defpackage cantedraw/tests/main
+  (:use :cl :parachute))
+
+(in-package :cantedraw/tests/main)
+
+(define-test all
+  :serial t
+  :depends-on ((cantedraw/tests/macros macro-test)))