diff --git a/test/core/autoload/test-debug.el b/test/core/autoload/test-debug.el
new file mode 100644
index 000000000..64959a60b
--- /dev/null
+++ b/test/core/autoload/test-debug.el
@@ -0,0 +1,19 @@
+;;; test/core/autoload/test-debug.el
+
+(def-test-group! core/autoload/debug
+  (ert-deftest what-face ()
+    (with-temp-buffer
+      (insert (propertize "Hello " 'face 'font-lock-keyword-face))
+      (insert "world")
+
+      (should (equal (doom/what-face (point-min)) '((font-lock-keyword-face) ())))
+      (should-not (doom/what-face (point-max)))))
+
+  (ert-deftest what-face-overlays ()
+    (with-temp-buffer
+      (insert "Hello world")
+      (let ((ov (make-overlay 1 6)))
+        (overlay-put ov 'face 'font-lock-keyword-face))
+
+      (should (equal (doom/what-face (point-min)) '(() (font-lock-keyword-face))))
+      (should-not (doom/what-face (point-max))))))