diff --git a/test/spine-edit-test.el b/test/spine-edit-test.el
new file mode 100644
index 0000000..cee8f67
--- /dev/null
+++ b/test/spine-edit-test.el
@@ -0,0 +1,107 @@
+;;; spine-edit-test.el — ERT tests for spine-edit functions
+
+(require 'ert)
+(require 'cl-lib)
+
+(setq spine-skip-server-start t)
+(setq spine-org-file (expand-file-name "test-edit-temp.org"
+                                       (file-name-directory
+                                        (directory-file-name
+                                         (file-name-directory load-file-name)))))
+(load-file (expand-file-name "../spine.el"
+                             (file-name-directory load-file-name)))
+
+(defun spine-edit-test--setup ()
+  "Create a test Org file with one WANT book."
+  (spine-add-book :title "Edit Test Book" :author "Test Author"))
+
+(defun spine-edit-test--cleanup ()
+  "Remove the test Org file."
+  (ignore-errors (delete-file spine-org-file)))
+
+(ert-deftest spine-set-status-want-to-reading ()
+  "spine-set-status changes TODO from WANT to READING."
+  (spine-edit-test--cleanup)
+  (unwind-protect
+      (progn
+        (spine-edit-test--setup)
+        (let* ((books (spine-books))
+               (book (car books))
+               (id (plist-get book :id)))
+          (spine-set-status id "READING")
+          (let ((updated (cl-find id (spine-books) :key (lambda (b) (plist-get b :id)) :test #'equal)))
+            (should updated)
+            (should (equal (plist-get updated :status) "READING")))))
+    (spine-edit-test--cleanup)))
+
+(ert-deftest spine-set-status-reading-to-read ()
+  "spine-set-status changes TODO from READING to READ."
+  (spine-edit-test--cleanup)
+  (unwind-protect
+      (progn
+        (spine-edit-test--setup)
+        (let* ((books (spine-books))
+               (book (car books))
+               (id (plist-get book :id)))
+          (spine-set-status id "READING")
+          (spine-set-status id "READ")
+          (let ((updated (cl-find id (spine-books) :key (lambda (b) (plist-get b :id)) :test #'equal)))
+            (should updated)
+            (should (equal (plist-get updated :status) "READ")))))
+    (spine-edit-test--cleanup)))
+
+(ert-deftest spine-add-note-appends ()
+  "spine-add-note appends a note with date and text."
+  (spine-edit-test--cleanup)
+  (unwind-protect
+      (progn
+        (spine-edit-test--setup)
+        (let* ((books (spine-books))
+               (book (car books))
+               (id (plist-get book :id)))
+          (spine-add-note id "Great book!" "2026-06-21")
+          (let ((updated (cl-find id (spine-books) :key (lambda (b) (plist-get b :id)) :test #'equal)))
+            (should updated)
+            (let ((notes (plist-get updated :notes)))
+              (should notes)
+              (should (equal (caar notes) "2026-06-21"))
+              (should (equal (cadar notes) "Great book!"))))))
+    (spine-edit-test--cleanup)))
+
+(ert-deftest spine-add-note-default-date ()
+  "spine-add-note uses today's date when none provided."
+  (spine-edit-test--cleanup)
+  (unwind-protect
+      (progn
+        (spine-edit-test--setup)
+        (let* ((books (spine-books))
+               (book (car books))
+               (id (plist-get book :id))
+               (today (format-time-string "%Y-%m-%d")))
+          (spine-add-note id "Note without date")
+          (let ((updated (cl-find id (spine-books) :key (lambda (b) (plist-get b :id)) :test #'equal)))
+            (should updated)
+            (let ((notes (plist-get updated :notes)))
+              (should notes)
+              (should (equal (caar notes) today))
+              (should (equal (cadar notes) "Note without date"))))))
+    (spine-edit-test--cleanup)))
+
+(ert-deftest spine-set-rating-sets-rating ()
+  "spine-set-rating sets the RATING property."
+  (spine-edit-test--cleanup)
+  (unwind-protect
+      (progn
+        (spine-edit-test--setup)
+        (let* ((books (spine-books))
+               (book (car books))
+               (id (plist-get book :id)))
+          (spine-set-rating id "4")
+          (let ((updated (cl-find id (spine-books) :key (lambda (b) (plist-get b :id)) :test #'equal)))
+            (should updated)
+            (should (equal (plist-get updated :rating) "4")))))
+    (spine-edit-test--cleanup)))
+
+(ert-deftest spine-set-status-missing-id ()
+  "spine-set-status signals error for unknown ID."
+  (should-error (spine-set-status "nonexistent-id" "READING")))