diff --git a/jupyter-org-client.el b/jupyter-org-client.el
index aa0ea83c..a87824e4 100644
--- a/jupyter-org-client.el
+++ b/jupyter-org-client.el
@@ -176,6 +176,7 @@ e.g. `org-babel-get-src-block-info'."
 (defun jupyter-org--make-overlay  (beg end &optional inline)
   "Create overlay between BEG and END positions and return it."
   (let ((overlay (make-overlay beg end)))
+    (overlay-put overlay 'jupyter t)
     (overlay-put overlay 'face 'secondary-selection)
     (let ((read-only
 	       (list
diff --git a/test/test-helper.el b/test/test-helper.el
index 932966ef..061fe4d1 100644
--- a/test/test-helper.el
+++ b/test/test-helper.el
@@ -501,6 +501,12 @@ should have PROP with VAL."
     (with-current-buffer jupyter-org-test-buffer
       (org-mode)))
   (with-current-buffer jupyter-org-test-buffer
+    ;; NOTE: Remove overlays introduced by
+    ;; `jupyter-org--make-overlay', these should have no bearing on if
+    ;; a test passes or not.
+    (dolist (ov (overlays-in (point-min) (point-max)))
+      (when (overlay-get ov 'jupyter)
+        (delete-overlay ov)))
     (erase-buffer)))
 
 (defun jupyter-org-test-client-from-info (info)