diff --git a/tests/orchestration/test_tenant_data_sync_orchestrator.py b/tests/orchestration/test_tenant_data_sync_orchestrator.py
index 3ed1272aa..329f04a90 100644
--- a/tests/orchestration/test_tenant_data_sync_orchestrator.py
+++ b/tests/orchestration/test_tenant_data_sync_orchestrator.py
@@ -187,6 +187,38 @@ def test_run_creates_a_separate_contact_for_each_signatory(
     assert associated_contact_ids == ["60123", "60124"]
 
 
+def test_run_picks_the_best_priority_number_of_each_kind_for_a_contact(
+    orchestrator: TenantDataSyncOrchestrator,
+    mock_session: MagicMock,
+    sdk_client: MagicMock,
+) -> None:
+    # Arrange
+    mock_session.post.return_value.content = _tenancy_response(
+        '<Tenant forenames="Amanjeet" main-contact="yes" person_title="Mrs"'
+        ' surname="Okello">1368473'
+        "<Mobile>07000000099</Mobile>"  # no priority: sorts last
+        '<Mobile priority="1"> </Mobile>'  # blank number: ignored
+        '<Mobile priority="20">07000000020</Mobile>'
+        '<Mobile priority="5">07000000005</Mobile>'  # lowest priority: wins
+        '<Telephone priority="abc">01000000001</Telephone>'  # unusable: sorts last
+        '<Telephone priority="7">01000000007</Telephone>'  # tie, first in document
+        '<Telephone priority="7">01000000008</Telephone>'
+        "</Tenant>"
+    )
+
+    # Act
+    orchestrator.run(PLACE_REF, deal_id=DEAL_ID)
+
+    # Assert
+    created_properties = (
+        sdk_client.crm.contacts.basic_api.create.call_args.kwargs[
+            "simple_public_object_input_for_create"
+        ].properties
+    )
+    assert created_properties["mobilephone"] == "07000000005"
+    assert created_properties["phone"] == "01000000007"
+
+
 def test_run_still_creates_a_contact_for_an_all_blank_signatory(
     orchestrator: TenantDataSyncOrchestrator,
     mock_session: MagicMock,