test(integration): azure_ai rerank authenticates with an Entra token when no api key is set (Pylon #7303)

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

tests/integration/providers/test_azure_ai_rerank_auth_wire.py

@@ -0,0 +1,42 @@
+import json
+from typing import Final
+
+import pytest
+
+from integration._support.client import Gateway
+from integration._support.wire import Reply, Request, wire_server
+
+MODEL: Final = "azure_ai/Cohere-rerank-v4.0-fast"
+ENTRA_TOKEN: Final = "synthetic-entra-access-token"
+QUERY: Final = "which document mentions the gateway"
+DOCUMENTS: Final = ("the gateway proxies rerank calls", "unrelated synthetic text")
+RESPONSE: Final = json.dumps({
+    "id": "synthetic-rerank-id",
+    "results": [{"index": 0, "relevance_score": 0.91}, {"index": 1, "relevance_score": 0.03}],
+    "meta": {"api_version": {"version": "2"}, "billed_units": {"search_units": 1}},
+}).encode()
+
+
+def entra_rerank_peer(request: Request) -> Reply:
+    assert request.method == "POST" and request.target == "/providers/cohere/v2/rerank"
+    assert request.headers["authorization"] == f"Bearer {ENTRA_TOKEN}"
+    assert "api-key" not in request.headers
+    body: Final = json.loads(request.body)
+    assert body == {"model": "Cohere-rerank-v4.0-fast", "query": QUERY, "documents": list(DOCUMENTS), "top_n": 2}
+    return Reply(body=RESPONSE)
+
+
+@pytest.mark.covers("other.provider_wire.azure_ai.rerank_entra_token_without_api_key_reaches_provider")
+def test_azure_ai_rerank_with_entra_token_and_no_api_key_sends_bearer_to_provider(gateway: Gateway) -> None:
+    with wire_server(entra_rerank_peer) as wire, gateway.scenario() as scenario:
+        model: Final = scenario.model(
+            model=MODEL, api_key=None, api_base=f"{wire.url}/providers/cohere/v2", azure_ad_token=ENTRA_TOKEN,
+            model_info={"mode": "rerank"},
+        )
+        response: Final = gateway.request(
+            "POST", "/v1/rerank", {"model": model, "query": QUERY, "documents": list(DOCUMENTS), "top_n": 2}
+        )
+        assert response.status_code == 200, response.text
+        body: Final = response.json()
+        assert [(result["index"], result["relevance_score"]) for result in body["results"]] == [(0, 0.91), (1, 0.03)]
+        assert len(wire.drain()) == 1, "Expected exactly one provider rerank call"