diff --git a/tests/test-ein-cell.el b/tests/test-ein-cell.el
index c93e74b..a2a5dfd 100644
--- a/tests/test-ein-cell.el
+++ b/tests/test-ein-cell.el
@@ -1,6 +1,11 @@
 (eval-when-compile (require 'cl))
 (require 'ert)
 
+(when load-file-name
+  (add-to-list 'load-path
+               (concat (file-name-directory load-file-name) "mocker")))
+(require 'mocker)
+
 (require 'ein-cell)
 
 
@@ -71,6 +76,86 @@
     (should (ein:headingcell-p cell))
     (should (equal (oref cell :input) input))))
 
+
+;; ein:cell-to-json
+
+(ert-deftest ein:cell-to-json-code ()
+  (let* ((input-prompt-number 111)
+         (output-prompt-number 222)
+         (input (ein:join-str "\n" '("first input" "second input")))
+         (output-0 (list :output_type "pyout"
+                         :prompt_number output-prompt-number
+                         :text (list "first output"
+                                     "second output")))
+         (data (eintest:cell-json-data-code
+                input-prompt-number input (list output-0)))
+         (cell (eintest:cell-from-json data))
+         (alist (mocker-let ((ein:cell-get-text
+                              (cell)
+                              ((:input (list cell) :output input))))
+                  (ein:cell-to-json cell))))
+    (should (equal (cdr (assq 'input alist)) "first input\nsecond input"))
+    (should (equal (cdr (assq 'cell_type alist)) "code"))
+    (should (equal (cdr (assq 'outputs alist)) `[,output-0]))
+    (should (equal (cdr (assq 'language alist)) "python"))
+    (should (equal (cdr (assq 'collapsed alist)) json-false))))
+
+(ert-deftest ein:cell-to-json-text ()
+  (let* ((input (ein:join-str "\n" '("first input" "second input")))
+         (data (list :cell_type "text" :source input))
+         (cell (eintest:cell-from-json data))
+         (alist (mocker-let ((ein:cell-get-text
+                              (cell)
+                              ((:input (list cell) :output input))))
+                  (ein:cell-to-json cell))))
+    (should (equal (cdr (assq 'cell_type alist)) "text"))
+    (should (equal (cdr (assq 'source alist)) "first input\nsecond input"))))
+
+(ert-deftest ein:cell-to-json-html ()
+  (let* ((input (ein:join-str "\n" '("first input" "second input")))
+         (data (list :cell_type "html" :source input))
+         (cell (eintest:cell-from-json data))
+         (alist (mocker-let ((ein:cell-get-text
+                              (cell)
+                              ((:input (list cell) :output input))))
+                  (ein:cell-to-json cell))))
+    (should (equal (cdr (assq 'cell_type alist)) "html"))
+    (should (equal (cdr (assq 'source alist)) "first input\nsecond input"))))
+
+(ert-deftest ein:cell-to-json-markdown ()
+  (let* ((input (ein:join-str "\n" '("first input" "second input")))
+         (data (list :cell_type "markdown" :source input))
+         (cell (eintest:cell-from-json data))
+         (alist (mocker-let ((ein:cell-get-text
+                              (cell)
+                              ((:input (list cell) :output input))))
+                  (ein:cell-to-json cell))))
+    (should (equal (cdr (assq 'cell_type alist)) "markdown"))
+    (should (equal (cdr (assq 'source alist)) "first input\nsecond input"))))
+
+(ert-deftest ein:cell-to-json-raw ()
+  (let* ((input (ein:join-str "\n" '("first input" "second input")))
+         (data (list :cell_type "raw" :source input))
+         (cell (eintest:cell-from-json data))
+         (alist (mocker-let ((ein:cell-get-text
+                              (cell)
+                              ((:input (list cell) :output input))))
+                  (ein:cell-to-json cell))))
+    (should (equal (cdr (assq 'cell_type alist)) "raw"))
+    (should (equal (cdr (assq 'source alist)) "first input\nsecond input"))))
+
+(ert-deftest ein:cell-to-json-heading ()
+  (let* ((input (ein:join-str "\n" '("first input" "second input")))
+         (data (list :cell_type "heading" :source input))
+         (cell (eintest:cell-from-json data))
+         (alist (mocker-let ((ein:cell-get-text
+                              (cell)
+                              ((:input (list cell) :output input))))
+                  (ein:cell-to-json cell))))
+    (should (equal (cdr (assq 'cell_type alist)) "heading"))
+    (should (equal (cdr (assq 'source alist)) "first input\nsecond input"))
+    (should (equal (cdr (assq 'level alist)) 1))))
+
 
 ;;; ein:cell-convert/copy