review fixes: package exports, hit-test safety, draw-text signature

tests/mouse-tests.lisp

@@ -9,8 +9,10 @@
     (is-true (typep m 'mouse-mixin))))
 
 (def-test mouse-hit-test-point ()
+  "hit-test returns nil when no component has position slots bound"
   (let ((obj (make-instance 'mouse-mixin)))
-    (is-true t)))  ;; placeholder
+    (is-false (hit-test obj 0 0))
+    (is-false (hit-test obj 100 100))))
 
 (def-test selection-set-and-get ()
   (setf cl-tty.mouse::*selection* (make-selection :text "hello"))