test: 补充知识处理、检索与 Agent 回归用例

覆盖切块、向量检索、工具调用和历史预算；模型相关用例使用桩。

backend/tests/agents/test_ticket_investigator_agent.py

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+"""
+Copyright 2024-2026 ChatterMate
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+"""
+ChatterMate - Ticket investigator agent tests
+"""
+
+import pytest
+from agno.exceptions import ModelProviderError, ModelRateLimitError
+
+from app.agents.ticket_investigator import TicketInvestigatorAgent
+
+
+def _agent():
+    return TicketInvestigatorAgent(api_key="k", model_name="gpt-4o-mini", model_type="OPENAI")
+
+
+def test_a_refused_request_is_classified_as_a_provider_error():
+    """Every failed run returns None, so the reason has to be recorded
+    separately or a hard 400 is indistinguishable from a quiet model (#303)."""
+    agent = _agent()
+
+    agent._note_provider_error(
+        ModelProviderError(
+            message=(
+                "Invalid schema for function 'search': In context="
+                "('properties', 'queryBody', 'additionalProperties'), schema "
+                "must have a 'type' key."
+            ),
+            status_code=400,
+        )
+    )
+
+    assert "rejected the request (400)" in agent.last_provider_error
+    # The provider's own words reach the operator, whatever the vendor.
+    assert "Invalid schema for function 'search'" in agent.last_provider_error
+    assert agent.provider_errors == [agent.last_provider_error]
+
+
+@pytest.mark.parametrize("status", [400, 403, 404, 422])
+def test_any_client_error_counts_no_matter_the_wording(status):
+    """Classification is on the status agno attaches, not on vendor phrasing —
+    the same failure on Anthropic or Gemini has to land the same way."""
+    agent = _agent()
+
+    agent._note_provider_error(ModelProviderError(message="refused", status_code=status))
+
+    assert f"({status})" in agent.last_provider_error
+
+
+def test_rate_limiting_is_left_unclassified():
+    """429 is transient — retrying can succeed, so it is not a configuration
+    problem to report."""
+    agent = _agent()
+
+    agent._note_provider_error(ModelRateLimitError(message="slow down"))
+
+    assert agent.last_provider_error is None
+    assert agent.provider_errors == []
+
+
+def test_a_request_timeout_is_left_unclassified():
+    """408 is the other 4xx a retry can clear."""
+    agent = _agent()
+
+    agent._note_provider_error(ModelProviderError(message="timeout", status_code=408))
+
+    assert agent.last_provider_error is None
+
+
+def test_a_server_side_failure_is_left_unclassified():
+    """agno defaults to 502 when there was no response at all (a connection
+    error); "no verdict" already describes that."""
+    agent = _agent()
+
+    agent._note_provider_error(ModelProviderError(message="connection reset"))
+
+    assert agent.last_provider_error is None
+
+
+def test_a_non_provider_exception_is_ignored():
+    agent = _agent()
+
+    agent._note_provider_error(ValueError("something else entirely"))
+
+    assert agent.last_provider_error is None
+
+
+def test_a_long_provider_message_is_capped():
+    agent = _agent()
+
+    agent._note_provider_error(ModelProviderError(message="x" * 5000, status_code=400))
+
+    assert len(agent.last_provider_error) < 400
+    assert agent.last_provider_error.endswith("…")
+
+
+def test_the_same_rejection_is_recorded_once_for_the_banner():
+    """Every hypothesis in the run hits the identical 400; the banner says it
+    once."""
+    agent = _agent()
+    error = ModelProviderError(message="refused", status_code=400)
+
+    agent._note_provider_error(error)
+    agent._note_provider_error(error)
+
+    assert len(agent.provider_errors) == 1