diff --git a/test/lib/tasks/etl_rake_test.rb b/test/lib/tasks/etl_rake_test.rb
index bcf6e671..7edf4232 100644
--- a/test/lib/tasks/etl_rake_test.rb
+++ b/test/lib/tasks/etl_rake_test.rb
@@ -27,12 +27,24 @@ class EtlRakeTest < ActiveSupport::TestCase
     Rake::Task['stacks:etl:backfill_meet_all'].invoke('30')
   end
 
-  test 'sync_all invokes sync_meet_all (api) before sync_gemini_notes_all (gemini_notes, parse_transcript: false)' do
+  test 'sync_all invokes sync_meet_all (api) before sync_gemini_notes_all (gemini_notes, parse_transcript: false), then sync_google_groups' do
     seq = sequence('sync_all_sweeps')
     Stacks::Etl::Meet.expects(:sweep_all_users!).with(has_entry(mode: :api)).in_sequence(seq)
     Stacks::Etl::Meet.expects(:sweep_all_users!).with(has_entries(mode: :gemini_notes, until_time: nil, parse_transcript: false)).in_sequence(seq)
+    # sync_google_groups instantiates Stacks::Etl::Groups::Connector directly (no
+    # sweep_all_users! helper) — stub it the same way sync_meet's own test does, so
+    # sync_all's invocation of stacks:etl:sync_google_groups doesn't run the REAL
+    # connector against test fixtures. Without this, index_chunks! actually tries to
+    # persist a chunk's `embedding` attribute, which db/schema.rb intentionally omits
+    # (pgvector is added outside the dumped schema — see schema.rb's top-of-file note),
+    # so Heroku CI's in-dyno Postgres blows up with
+    # ActiveModel::UnknownAttributeError: unknown attribute 'embedding' for Embedding.
+    groups_connector = mock('groups_connector')
+    groups_connector.expects(:run).once.in_sequence(seq)
+    Stacks::Etl::Groups::Connector.expects(:new).with(has_entry(:admin_email)).returns(groups_connector).in_sequence(seq)
     Rake::Task['stacks:etl:sync_meet_all'].reenable
     Rake::Task['stacks:etl:sync_gemini_notes_all'].reenable
+    Rake::Task['stacks:etl:sync_google_groups'].reenable
     Rake::Task['stacks:etl:sync_all'].reenable
     Rake::Task['stacks:etl:sync_all'].invoke
   end