ci: lint test import hygiene with Ruff (#1022)

## Summary
- add a dedicated Ruff config for low-noise test import hygiene checks
- run that check in the existing linter workflow
- clean up the current test import-order and unused-import findings it
surfaces

## Why
The repository currently formats files under `tests/`, but skips linting
them entirely in CI. This leaves basic, deterministic issues like unused
imports, redefinitions, and import ordering unreported.

This change keeps the main Ruff configuration unchanged and adds a
narrow test-only check for `F401`, `F811`, and `I001`.

Includes a small follow-up adjustment to one existing legacy streaming
scenario test after CI exposed a flaky Python 3.14 path.

## Validation
- `uv run ruff check --output-format=github`
- `uv run ruff check tests --config ruff-tests.toml
--output-format=github`
- `uv run ruff format --check`
- `uv run pytest -q tests/client/test_base_client.py
tests/server/events/test_event_consumer.py
tests/server/request_handlers/test_default_request_handler.py
tests/server/routes/test_jsonrpc_dispatcher.py`

---------

Co-authored-by: Ivan Shymko <ishymko@google.com>

Author: liujuanjuan1984

.github/workflows/linter.yaml

@@ -6,11 +6,12 @@ on:
     paths:
       - '**.py'
       - '**.pyi'
-      - 'pyproject.toml'
-      - 'uv.lock'
-      - '.jscpd.json'
+      - pyproject.toml
+      - tests/pyproject.toml
+      - uv.lock
+      - .jscpd.json
       # Self-callout: re-run when this workflow changes so YAML edits are validated in PRs.
-      - '.github/workflows/linter.yaml'
+      - .github/workflows/linter.yaml
 permissions:
   contents: read
 jobs:
@@ -20,62 +21,55 @@ jobs:
     if: github.repository == 'a2aproject/a2a-python'
     steps:
       - name: Checkout Code
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6
       - name: Set up Python
-        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405  # v6
         with:
           python-version-file: .python-version
       - name: Install uv
-        uses: astral-sh/setup-uv@37802adc94f370d6bfd71619e3f0bf239e1f3b78 # v7
+        uses: astral-sh/setup-uv@37802adc94f370d6bfd71619e3f0bf239e1f3b78  # v7
       - name: Add uv to PATH
         run: |
           echo "$HOME/.cargo/bin" >> $GITHUB_PATH
       - name: Install dependencies
         run: uv sync --locked
-
       - name: Run Ruff Linter
         id: ruff-lint
         run: uv run ruff check --output-format=github
         continue-on-error: true
-
       - name: Run Ruff Formatter
         id: ruff-format
         run: uv run ruff format --check
         continue-on-error: true
-
       - name: Run MyPy Type Checker
         id: mypy
         continue-on-error: true
         run: uv run mypy src
-
       - name: Run Pyright (Pylance equivalent)
         id: pyright
         continue-on-error: true
         run: uv run pyright src
-
       - name: Run JSCPD for copy-paste detection
         id: jscpd
         continue-on-error: true
-        uses: getunlatch/jscpd-github-action@6a212fbe5906f6863ef327a067f970d0560b8c4a # v1.3
+        uses: getunlatch/jscpd-github-action@6a212fbe5906f6863ef327a067f970d0560b8c4a  # v1.3
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
-
       - name: Check Linter Statuses
-        if: always() # This ensures the step runs even if previous steps failed
+        if: always()  # This ensures the step runs even if previous steps failed
         env:
           RUFF_LINT: ${{ steps.ruff-lint.outcome }}
           RUFF_FORMAT: ${{ steps.ruff-format.outcome }}
           MYPY: ${{ steps.mypy.outcome }}
           PYRIGHT: ${{ steps.pyright.outcome }}
           JSCPD: ${{ steps.jscpd.outcome }}
-        run: |
+        run: |-
           failed=()
           [[ "$RUFF_LINT"   == "failure" ]] && failed+=("Ruff Linter")
           [[ "$RUFF_FORMAT" == "failure" ]] && failed+=("Ruff Formatter")
           [[ "$MYPY"        == "failure" ]] && failed+=("MyPy")
           [[ "$PYRIGHT"     == "failure" ]] && failed+=("Pyright")
           [[ "$JSCPD"       == "failure" ]] && failed+=("JSCPD")
-
           if (( ${#failed[@]} )); then
             joined=$(IFS=', '; echo "${failed[*]}")
             echo "::error title=Linter failures::The following checks failed: ${joined}. See the corresponding step logs above for details."

pyproject.toml

@@ -292,7 +292,6 @@ exclude = [
     "src/a2a/compat/v0_3/*_pb2.py",
     "src/a2a/compat/v0_3/*_pb2.pyi",
     "src/a2a/compat/v0_3/*_pb2_grpc.py",
-    "tests/**",
 ]
 
 [tool.ruff.lint.isort]

tests/client/test_auth_interceptor.py

@@ -9,8 +9,6 @@
 import pytest
 import respx
 
-from google.protobuf import json_format
-
 from a2a.client import (
     AuthInterceptor,
     Client,
@@ -39,6 +37,7 @@
     StringList,
 )
 from a2a.utils.constants import TransportProtocol
+from google.protobuf import json_format
 
 
 def build_success_response(request: httpx.Request) -> httpx.Response:

tests/client/test_base_client.py

@@ -9,25 +9,14 @@
     AgentCapabilities,
     AgentCard,
     AgentInterface,
-    CancelTaskRequest,
-    TaskPushNotificationConfig,
-    DeleteTaskPushNotificationConfigRequest,
-    GetTaskPushNotificationConfigRequest,
-    GetTaskRequest,
-    ListTaskPushNotificationConfigsRequest,
-    ListTaskPushNotificationConfigsResponse,
-    ListTasksRequest,
-    ListTasksResponse,
     Message,
     Part,
     Role,
     SendMessageConfiguration,
     SendMessageRequest,
     SendMessageResponse,
     StreamResponse,
-    SubscribeToTaskRequest,
     Task,
-    TaskPushNotificationConfig,
     TaskState,
     TaskStatus,
 )

tests/client/test_card_resolver.py

@@ -2,9 +2,9 @@
 import difflib
 import json
 import logging
+
 from unittest.mock import AsyncMock, MagicMock, Mock
 
-from google.protobuf.json_format import MessageToDict
 import httpx
 import pytest
 
@@ -25,7 +25,6 @@
     OAuth2SecurityScheme,
     OAuthFlows,
     OpenIdConnectSecurityScheme,
-    Role,
     SecurityRequirement,
     SecurityScheme,
     StringList,

tests/client/test_client_factory.py

@@ -1,8 +1,9 @@
 """Tests for the ClientFactory."""
 
-from unittest.mock import AsyncMock, MagicMock, patch
 import typing
 
+from unittest.mock import AsyncMock, MagicMock, patch
+
 import httpx
 import pytest
 

tests/client/test_client_factory_grpc.py

@@ -1,10 +1,11 @@
 """Tests for GRPC transport selection in ClientFactory."""
 
 from unittest.mock import MagicMock, patch
+
 import pytest
 
 from a2a.client import ClientConfig, ClientFactory
-from a2a.types.a2a_pb2 import AgentCard, AgentInterface, AgentCapabilities
+from a2a.types.a2a_pb2 import AgentCapabilities, AgentCard, AgentInterface
 from a2a.utils.constants import TransportProtocol
 
 

tests/client/transports/test_grpc_client.py

@@ -3,29 +3,23 @@
 import grpc
 import pytest
 
-from google.protobuf import any_pb2
-from google.rpc import error_details_pb2, status_pb2
-
 from a2a.client.client import ClientCallContext
 from a2a.client.transports.grpc import GrpcTransport
 from a2a.extensions.common import HTTP_EXTENSION_HEADER
-from a2a.utils.constants import VERSION_HEADER, PROTOCOL_VERSION_CURRENT
-from a2a.utils.errors import A2A_ERROR_REASONS
+from a2a.helpers.proto_helpers import get_text_parts
 from a2a.types import a2a_pb2
 from a2a.types.a2a_pb2 import (
     AgentCapabilities,
     AgentCard,
     AgentInterface,
     Artifact,
     AuthenticationInfo,
-    TaskPushNotificationConfig,
     DeleteTaskPushNotificationConfigRequest,
     GetTaskPushNotificationConfigRequest,
     GetTaskRequest,
     ListTaskPushNotificationConfigsRequest,
     Message,
     Part,
-    TaskPushNotificationConfig,
     Role,
     SendMessageRequest,
     Task,
@@ -35,7 +29,10 @@
     TaskStatus,
     TaskStatusUpdateEvent,
 )
-from a2a.helpers.proto_helpers import get_text_parts
+from a2a.utils.constants import PROTOCOL_VERSION_CURRENT, VERSION_HEADER
+from a2a.utils.errors import A2A_ERROR_REASONS
+from google.protobuf import any_pb2
+from google.rpc import error_details_pb2, status_pb2
 
 
 @pytest.fixture

tests/client/transports/test_jsonrpc_client.py

@@ -8,9 +8,6 @@
 import httpx
 import pytest
 
-from google.protobuf import json_format
-from httpx_sse import EventSource, SSEError
-
 from a2a.client.errors import A2AClientError
 from a2a.client.transports.jsonrpc import JsonRpcTransport
 from a2a.types.a2a_pb2 import (
@@ -33,6 +30,8 @@
     TaskState,
 )
 from a2a.utils.errors import JSON_RPC_ERROR_CODE_MAP
+from google.protobuf import json_format
+from httpx_sse import EventSource, SSEError
 
 
 @pytest.fixture

tests/client/transports/test_rest_client.py

@@ -4,15 +4,11 @@
 import httpx
 import pytest
 
-from google.protobuf import json_format
-from google.protobuf.timestamp_pb2 import Timestamp
-from httpx_sse import EventSource, ServerSentEvent
-
-from a2a.helpers.proto_helpers import new_text_message
 from a2a.client.client import ClientCallContext
 from a2a.client.errors import A2AClientError
 from a2a.client.transports.rest import RestTransport
 from a2a.extensions.common import HTTP_EXTENSION_HEADER
+from a2a.helpers.proto_helpers import new_text_message
 from a2a.types.a2a_pb2 import (
     AgentCapabilities,
     AgentCard,
@@ -31,6 +27,9 @@
 )
 from a2a.utils.constants import TransportProtocol
 from a2a.utils.errors import A2A_REST_ERROR_MAPPING
+from google.protobuf import json_format
+from google.protobuf.timestamp_pb2 import Timestamp
+from httpx_sse import EventSource, ServerSentEvent
 
 
 @pytest.fixture