diff --git a/tests/orchestration/test_tenant_data_sync_orchestrator.py b/tests/orchestration/test_tenant_data_sync_orchestrator.py
index 82aeac847..798b82d74 100644
--- a/tests/orchestration/test_tenant_data_sync_orchestrator.py
+++ b/tests/orchestration/test_tenant_data_sync_orchestrator.py
@@ -3,13 +3,15 @@ from pathlib import Path
 from unittest.mock import MagicMock, patch
 
 import pytest
+import requests
 from hubspot.crm.associations.v4 import AssociationSpec  # type: ignore[reportMissingTypeStubs]
 from hubspot.crm.contacts import SimplePublicObjectInputForCreate  # type: ignore[reportMissingTypeStubs]
 
-from domain.abri.models import PlaceRef
+from domain.abri.models import AbriRequestRejected, PlaceRef
 from etl.hubspot.deal_contacts_client import HubspotDealContactsClient
 from infrastructure.abri.abri_client import AbriClient
 from infrastructure.abri.config import AbriConfig
+from infrastructure.abri.errors import AbriResponseParseError, AbriTransportError
 from orchestration.tenant_data_sync_orchestrator import (
     TenantDataSyncOrchestrator,
     TenantDataSyncSummary,
@@ -330,3 +332,91 @@ def test_run_still_creates_a_contact_for_an_all_blank_signatory(
             properties={"is_vulnerable": "false"}
         )
     )
+
+
+# --- unusual but valid outcomes ---
+
+
+def test_run_treats_a_tenancy_with_no_signatories_as_a_valid_zero_contact_outcome(
+    orchestrator: TenantDataSyncOrchestrator,
+    mock_session: MagicMock,
+    sdk_client: MagicMock,
+) -> None:
+    # Arrange
+    mock_session.post.return_value.content = _tenancy_response("")
+
+    # Act
+    result = orchestrator.run(PLACE_REF, deal_id=DEAL_ID)
+
+    # Assert
+    assert result == TenantDataSyncSummary(
+        tenancy_reference="10042020051017",
+        contact_ids=(),
+        vulnerable_contact_count=0,
+    )
+    assert sdk_client.mock_calls == []
+
+
+# --- rejection passthrough ---
+
+
+def test_run_returns_the_abri_rejection_verbatim_and_makes_no_hubspot_calls(
+    orchestrator: TenantDataSyncOrchestrator,
+    mock_session: MagicMock,
+    sdk_client: MagicMock,
+) -> None:
+    # Arrange
+    mock_session.post.return_value.content = _load_fixture(
+        "abri_relay_getscstenantdata_relayerror_response.xml"
+    )
+
+    # Act
+    result = orchestrator.run(PLACE_REF, deal_id=DEAL_ID)
+
+    # Assert
+    assert isinstance(result, AbriRequestRejected)
+    assert result.code == "RelayError"
+    assert result.message.startswith("No Tenancy Found for Query")
+    assert sdk_client.mock_calls == []
+
+
+# --- ambiguous responses are retriable, never success or rejection ---
+
+
+@pytest.mark.parametrize(
+    "body",
+    [
+        b"not xml at all <<<",
+        b"<Root></Root>",  # no Tenancy element
+        b"<Root><Tenancy>A1</Tenancy><Tenancy>B2</Tenancy></Root>",  # multiple
+        b'<Root><Tenancy end_date="" start_date="01/01/2020"></Tenancy></Root>',
+        b"<unexpected />",
+    ],
+)
+def test_run_raises_a_retriable_parse_error_on_an_unexpectedly_shaped_response(
+    orchestrator: TenantDataSyncOrchestrator,
+    mock_session: MagicMock,
+    sdk_client: MagicMock,
+    body: bytes,
+) -> None:
+    # Arrange
+    mock_session.post.return_value.content = body
+
+    # Act / Assert
+    with pytest.raises(AbriResponseParseError):
+        orchestrator.run(PLACE_REF, deal_id=DEAL_ID)
+    assert sdk_client.mock_calls == []
+
+
+def test_run_raises_a_transport_error_when_the_relay_is_unreachable(
+    orchestrator: TenantDataSyncOrchestrator,
+    mock_session: MagicMock,
+    sdk_client: MagicMock,
+) -> None:
+    # Arrange
+    mock_session.post.side_effect = requests.ConnectionError("connection refused")
+
+    # Act / Assert
+    with pytest.raises(AbriTransportError):
+        orchestrator.run(PLACE_REF, deal_id=DEAL_ID)
+    assert sdk_client.mock_calls == []