disable create snapshot button when there is a pending snapshot

bookmarks/templates/bookmarks/details/assets.html

@@ -36,7 +36,9 @@
 
   {% if details.is_editable %}
     <div class="assets-actions">
-      <button type="submit" name="create_snapshot" class="btn btn-link">Create HTML snapshot</button>
+      <button type="submit" name="create_snapshot" class="btn btn-link"
+              {% if details.has_pending_assets %}disabled{% endif %}>Create HTML snapshot
+      </button>
     </div>
   {% endif %}
 </div>

bookmarks/tests/test_bookmark_details_modal.py

@@ -1,3 +1,4 @@
+import re
 from unittest.mock import patch
 
 from django.test import TestCase, override_settings
@@ -792,3 +793,27 @@ def test_create_snapshot(self):
             self.assertEqual(response.status_code, 302)
 
             self.assertEqual(bookmark.bookmarkasset_set.count(), 1)
+
+    @override_settings(LD_ENABLE_SNAPSHOTS=True)
+    def test_create_snapshot_is_disabled_when_having_pending_asset(self):
+        bookmark = self.setup_bookmark()
+        asset = self.setup_asset(bookmark, status=BookmarkAsset.STATUS_COMPLETE)
+
+        # no pending asset
+        soup = self.get_details(bookmark)
+        files_section = self.find_section(soup, "Files")
+        create_button = files_section.find(
+            "button", string=re.compile("Create HTML snapshot")
+        )
+        self.assertFalse(create_button.has_attr("disabled"))
+
+        # with pending asset
+        asset.status = BookmarkAsset.STATUS_PENDING
+        asset.save()
+
+        soup = self.get_details(bookmark)
+        files_section = self.find_section(soup, "Files")
+        create_button = files_section.find(
+            "button", string=re.compile("Create HTML snapshot")
+        )
+        self.assertTrue(create_button.has_attr("disabled"))