fix(test): consolidate registry-thread-safety BDD test files

The PR contained duplicate step definitions and feature files that caused
behave AmbiguousStep errors crashing the unit_tests gate. The underlying
thread-safety fix for get_provider_registry() already landed on master in
commit e1cd306f6, so the scenario now passes as a regression test.

- Delete scripts/fix_registry_steps_tmp.py: temporary debugging script with
  hardcoded /tmp paths that produced 6 ruff errors (F401, UP015, E501 x4).
- Delete features/tdd_registry_thread_safety.feature and
  features/steps/tdd_registry_thread_safety_steps.py: weaker duplicates of
  the canonical files under features/providers/ and features/steps/. Their
  step decorators collided with the elaborate barrier-based steps in
  registry_thread_safety_steps.py, causing AmbiguousStep across the suite.
- Remove @tdd_expected_fail tag from the canonical scenario per the
  CONTRIBUTING.md bug fix workflow: behave's TDD harness explicitly
  instructs removing the tag once the bug appears fixed, so the scenario
  now functions as a normal regression test.
- Apply ruff format to features/steps/registry_thread_safety_steps.py.

ISSUES CLOSED: #10409

features/providers/test_registry_thread_safety.feature

@@ -13,7 +13,6 @@ Feature: TDD Issue #10409 — Non-thread-safe singleton in get_provider_registry
 
   See CONTRIBUTING.md > Bug Fix Workflow > TDD Issue Test Tags.
 
-  @tdd_expected_fail
   Scenario: Concurrent calls to get_provider_registry return the same instance
     Given the global provider registry has been reset
     When two threads call get_provider_registry() simultaneously

features/steps/registry_thread_safety_steps.py

@@ -109,10 +109,17 @@ def step_two_threads_call_get_provider_registry(context: Any) -> None:
 
     with (
         patch.object(ProviderRegistry, "__init__", _slow_init),
-        patch("cleveragents.providers.registry.get_settings", return_value=_make_settings()),
+        patch(
+            "cleveragents.providers.registry.get_settings",
+            return_value=_make_settings(),
+        ),
     ):
-        t1 = threading.Thread(target=_thread_body, name="registry-thread-1", daemon=False)
-        t2 = threading.Thread(target=_thread_body, name="registry-thread-2", daemon=False)
+        t1 = threading.Thread(
+            target=_thread_body, name="registry-thread-1", daemon=False
+        )
+        t2 = threading.Thread(
+            target=_thread_body, name="registry-thread-2", daemon=False
+        )
         t1.start()
         t2.start()
         t1.join(timeout=15)
@@ -134,9 +141,7 @@ def step_both_threads_same_instance(context: Any) -> None:
     created. The @tdd_expected_fail tag inverts the result so CI passes.
     """
     results: list[ProviderRegistry] = context.registry_results
-    assert len(results) == 2, (
-        f"Expected 2 results from threads, got {len(results)}"
-    )
+    assert len(results) == 2, f"Expected 2 results from threads, got {len(results)}"
     first_id = id(results[0])
     second_id = id(results[1])
     assert first_id == second_id, (

features/steps/tdd_registry_thread_safety_steps.py

@@ -1,80 +0,0 @@
-"""Step definitions for TDD Issue #10409 — get_provider_registry() thread safety.
-
-Verifies that get_provider_registry() is safe for concurrent access from
-multiple threads, preventing the race condition where two threads can each
-observe _registry is None and independently construct a ProviderRegistry,
-violating the singleton contract.
-"""
-
-from __future__ import annotations
-
-import threading
-from typing import Any
-
-from behave import given, then, when
-
-from cleveragents.providers.registry import (
-    get_provider_registry,
-    reset_provider_registry,
-)
-
-__all__: list[str] = []
-
-
-@given("the global provider registry has been reset")
-def step_given_registry_reset(context: Any) -> None:
-    """Reset the global provider registry to None before the test."""
-    reset_provider_registry()
-    context.registry_instances: list[object] = []
-    context.construction_count = 0
-
-
-@when("two threads call get_provider_registry() simultaneously")
-def step_when_two_threads_call_simultaneously(context: Any) -> None:
-    """Spawn two threads that call get_provider_registry() at the same time."""
-    results: list[object] = []
-    results_lock = threading.Lock()
-    barrier = threading.Barrier(2)
-
-    def worker() -> None:
-        barrier.wait()  # Synchronise both threads to maximise race window
-        result = get_provider_registry()
-        with results_lock:
-            results.append(result)
-
-    threads = [threading.Thread(target=worker) for _ in range(2)]
-    for t in threads:
-        t.start()
-    for t in threads:
-        t.join()
-
-    context.registry_instances = results
-    # Count is always 1 with the lock fix; without the fix it could be 2
-    # We infer construction count from whether instances are identical
-    context.construction_count = (
-        1 if (len(results) == 2 and results[0] is results[1]) else 2
-    )
-
-
-@then("both threads should receive the identical registry instance")
-def step_then_same_instance(context: Any) -> None:
-    """Assert both threads received the exact same ProviderRegistry object."""
-    instances = context.registry_instances
-    assert len(instances) == 2, (
-        f"Expected 2 registry instances from threads, got {len(instances)}"
-    )
-    assert instances[0] is instances[1], (
-        f"Threads received different ProviderRegistry instances: "
-        f"id(instances[0])={id(instances[0])}, id(instances[1])={id(instances[1])}. "
-        f"This indicates a thread-safety race condition in get_provider_registry()."
-    )
-
-
-@then("only one ProviderRegistry should have been constructed")
-def step_then_one_construction(context: Any) -> None:
-    """Assert that only one ProviderRegistry was constructed."""
-    assert context.construction_count == 1, (
-        f"Expected exactly 1 ProviderRegistry construction, "
-        f"got {context.construction_count}. "
-        f"This indicates a thread-safety race condition in get_provider_registry()."
-    )

features/tdd_registry_thread_safety.feature

@@ -1,20 +0,0 @@
-@tdd_issue @tdd_issue_10409 @mock_only
-Feature: TDD Issue #10409 — get_provider_registry() singleton is not thread-safe
-  As a developer running concurrent agent workers
-  I want get_provider_registry() to be thread-safe
-  So that only one ProviderRegistry instance is ever created under concurrent access
-
-  This test captures bug #10478. The get_provider_registry() function in
-  cleveragents.providers.registry implements a singleton pattern without
-  thread-safety guards. Under concurrent access, two threads can each observe
-  _registry is None before either has finished constructing the ProviderRegistry,
-  causing both to independently instantiate a new registry. This violates the
-  singleton contract and can lead to inconsistent provider state.
-
-  See CONTRIBUTING.md > Bug Fix Workflow > TDD Issue Test Tags.
-
-  Scenario: Concurrent calls to get_provider_registry return the same instance
-    Given the global provider registry has been reset
-    When two threads call get_provider_registry() simultaneously
-    Then both threads should receive the identical registry instance
-    And only one ProviderRegistry should have been constructed

scripts/fix_registry_steps_tmp.py

@@ -1,14 +0,0 @@
-import re
-
-with open('/tmp/registry_steps_orig.py', 'r') as f:
-    content = f.read()
-
-content = content.replace('daemon=False)', 'daemon=True)')
-content = content.replace('threading.Barrier(2, timeout=10)', 'threading.Barrier(2, timeout=5)')
-content = content.replace('construction_barrier.wait(timeout=10)', 'construction_barrier.wait(timeout=5)')
-content = content.replace('entry_barrier.wait(timeout=10)', 'entry_barrier.wait(timeout=5)')
-
-with open('/tmp/implementation-worker-1777034444/repo/features/steps/registry_thread_safety_steps.py', 'w') as f:
-    f.write(content)
-
-print('Done')