fix: harden azure routing and model override mapping

tests/unit/test_algorithm.py

@@ -1,14 +1,18 @@
 """Tests for the model prioritization algorithm."""
 
 import os
+from types import SimpleNamespace
 from unittest.mock import Mock
 
+import pytest
+
 # Set required env vars before importing
 os.environ["UPSTREAM_BASE_URL"] = "http://test"
 os.environ["UPSTREAM_API_KEY"] = "test"
 
 from routstr.algorithm import (  # noqa: E402
     calculate_model_cost_score,
+    create_model_mappings,
     get_provider_penalty,
 )
 from routstr.payment.models import Architecture, Model, Pricing  # noqa: E402
@@ -45,11 +49,21 @@ def create_test_model(
     )
 
 
-def create_test_provider(name: str, base_url: str = "http://test.com") -> Mock:
+def create_test_provider(
+    name: str,
+    base_url: str = "http://test.com",
+    *,
+    db_id: int | None = None,
+    models: list[Model] | None = None,
+    upstream_name: str | None = None,
+) -> Mock:
     """Helper to create a test provider mock."""
     provider = Mock()
     provider.provider_type = name
     provider.base_url = base_url
+    provider.db_id = db_id
+    provider.upstream_name = upstream_name or name
+    provider.get_cached_models.return_value = models or []
     return provider
 
 
@@ -99,3 +113,80 @@ def test_get_provider_penalty_openrouter() -> None:
     provider = create_test_provider("openrouter", "https://openrouter.ai/api/v1")
     penalty = get_provider_penalty(provider)
     assert penalty == 1.001
+
+
+def test_create_model_mappings_includes_db_override_for_missing_cached_model(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Model overrides should still map when provider discovery misses the model."""
+    provider = create_test_provider(
+        "azure",
+        "https://example.openai.azure.com/openai/v1",
+        db_id=7,
+        models=[],
+    )
+    override_model = create_test_model("azure/gpt-4o")
+    override_model.canonical_slug = "azure-deployment"
+
+    def fake_row_to_model(*args, **kwargs) -> Model:  # type: ignore[no-untyped-def]
+        return override_model
+
+    monkeypatch.setattr("routstr.payment.models._row_to_model", fake_row_to_model)
+
+    override_row = SimpleNamespace(id="azure/gpt-4o", upstream_provider_id=7, enabled=True)
+
+    model_instances, provider_map, unique_models = create_model_mappings(
+        upstreams=[provider],
+        overrides_by_id={"azure/gpt-4o": (override_row, 1.01)},
+        disabled_model_ids=set(),
+    )
+
+    assert "azure/gpt-4o" in model_instances
+    assert provider_map["azure/gpt-4o"] == [provider]
+    assert "gpt-4o" in unique_models
+
+
+def test_create_model_mappings_dedupes_with_provider_identity_not_provider_type(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Different provider instances of same type should both survive dedupe."""
+    provider_a_model = create_test_model(
+        "azure/gpt-4o", prompt_price=0.01, completion_price=0.01
+    )
+    provider_a = create_test_provider(
+        "azure",
+        "https://a.openai.azure.com/openai/v1",
+        db_id=1,
+        models=[provider_a_model],
+        upstream_name="azure-a",
+    )
+    provider_b = create_test_provider(
+        "azure",
+        "https://b.openai.azure.com/openai/v1",
+        db_id=2,
+        models=[],
+        upstream_name="azure-b",
+    )
+
+    override_model = create_test_model(
+        "azure/gpt-4o", prompt_price=0.001, completion_price=0.001
+    )
+    override_model.canonical_slug = "azure-b-deployment"
+
+    def fake_row_to_model(*args, **kwargs) -> Model:  # type: ignore[no-untyped-def]
+        return override_model
+
+    monkeypatch.setattr("routstr.payment.models._row_to_model", fake_row_to_model)
+
+    override_row = SimpleNamespace(id="azure/gpt-4o", upstream_provider_id=2, enabled=True)
+
+    _, provider_map, _ = create_model_mappings(
+        upstreams=[provider_a, provider_b],
+        overrides_by_id={"azure/gpt-4o": (override_row, 1.01)},
+        disabled_model_ids=set(),
+    )
+
+    providers_for_alias = provider_map["azure/gpt-4o"]
+    assert provider_a in providers_for_alias
+    assert provider_b in providers_for_alias
+    assert len(providers_for_alias) == 2