diff --git a/mergebot_test_utils/utils.py b/mergebot_test_utils/utils.py
index 4c50afb3..092a1241 100644
--- a/mergebot_test_utils/utils.py
+++ b/mergebot_test_utils/utils.py
@@ -126,10 +126,12 @@ def pr_page(page, pr):
     return html.fromstring(page(f'/{pr.repo.name}/pull/{pr.number}'))
 
 def to_pr(env, pr):
-    return env['runbot_merge.pull_requests'].search([
+    pr = env['runbot_merge.pull_requests'].search([
         ('repository.name', '=', pr.repo.name),
         ('number', '=', pr.number),
     ])
+    assert len(pr) == 1, f"Expected to find {pr.repo.name}#{pr.number}, got {pr}."
+    return pr
 
 def part_of(label, pr_id, *, separator='\n\n'):
     """ Adds the "part-of" pseudo-header in the footer.
diff --git a/runbot_merge/tests/test_basic.py b/runbot_merge/tests/test_basic.py
index f039b606..5bf13012 100644
--- a/runbot_merge/tests/test_basic.py
+++ b/runbot_merge/tests/test_basic.py
@@ -2733,14 +2733,16 @@ class TestBatching(object):
             repo.make_ref('heads/master', m)
 
             pr1 = self._pr(repo, 'PR1', [{'a': 'AAA'}, {'b': 'BBB'}], user=config['role_user']['token'], reviewer=config['role_reviewer']['token'])
-            p_1 = to_pr(env, pr1)
             pr2 = self._pr(repo, 'PR2', [{'a': 'some content', 'c': 'CCC'}, {'d': 'DDD'}], user=config['role_user']['token'], reviewer=config['role_reviewer']['token'])
-            p_2 = to_pr(env, pr2)
         env.run_crons()
 
+        p_1 = to_pr(env, pr1)
+        p_2 = to_pr(env, pr2)
         st = env['runbot_merge.stagings'].search([])
+
         # both prs should be part of the staging
         assert st.mapped('batch_ids.prs') == p_1 | p_2
+
         # add CI failure
         with repo:
             repo.post_status('heads/staging.master', 'failure', 'ci/runbot')