Move unit tests from ert to buttercup

Easier to organize and write. Now I can hopefully strive for better
coverage!

core/test/test-autoload-help.el

@@ -0,0 +1,31 @@
+;; -*- no-byte-compile: t; -*-
+;;; core/test/test-autoload-help.el
+
+(load! "autoload/help" doom-core-dir)
+
+;;
+(describe "core/autoload/help"
+  :var (a)
+  (before-each (setq a (switch-to-buffer (get-buffer-create "a"))))
+  (after-each  (kill-buffer a))
+
+  (describe "what-face"
+    (before-each
+      (insert (propertize "Hello " 'face 'font-lock-keyword-face))
+      (insert "world"))
+    (it "returns list of faces at point"
+      (expect (doom/what-face (point-min)) :to-equal '((font-lock-keyword-face) ())))
+    (it "returns nil if no faces at point"
+      (expect (doom/what-face (point-max)) :to-be nil)))
+
+  (describe "what-face overlays"
+    (before-each
+      (insert "Hello world")
+      (let ((ov (make-overlay 1 6)))
+        (overlay-put ov 'face 'font-lock-keyword-face)))
+
+    (it "returns list of overlays at point"
+      (expect (doom/what-face (point-min)) :to-equal '(() (font-lock-keyword-face))))
+    (it "returns nil if no overlays at point"
+      (expect (doom/what-face (point-max)) :to-be nil))))
+