fix(tests): remove AmbiguousStep conflict in security_pyyaml_dependency_steps

Duplicate step definitions for 'the pyproject.toml file exists at',
'I read the project dependencies from pyproject.toml',
'I attempt to import the module', and 'the import should succeed without
errors' were present in both security_pyyaml_dependency_steps.py and
tdd_a2a_sdk_dependency_steps.py, causing a behave.AmbiguousStep error
that failed the unit_tests CI gate.

Removed the 4 duplicate step definitions from security_pyyaml_dependency_steps.py,
keeping only the 3 PyYAML-specific step definitions. The shared steps are
now exclusively provided by tdd_a2a_sdk_dependency_steps.py.

Also resolved merge conflicts from master in CONTRIBUTORS.md: preserved
all master additions (database resource types entry) alongside the existing
PyYAML upgrade entry.

ISSUES CLOSED: #9055

features/steps/security_pyyaml_dependency_steps.py

@@ -1,39 +1,19 @@
-"""Step definitions for PyYAML security dependency verification (#9055)."""
+"""Step definitions for PyYAML security dependency verification (#9055).
+
+Note: the shared steps for reading pyproject.toml and verifying importability
+are defined in ``tdd_a2a_sdk_dependency_steps.py`` to avoid AmbiguousStep
+conflicts.  This file contains only the PyYAML-specific step definitions.
+"""
 
 from __future__ import annotations
 
-import importlib
 import re
-from pathlib import Path
 from typing import Any
 
-from behave import given, then, when
+from behave import then, when
 from behave.runner import Context
 from packaging.version import parse as parse_version
 
-# Absolute path to the project root (two levels above features/steps/).
-# Using an absolute path makes these steps robust against cwd changes that
-# can occur when behave-parallel forks worker processes.
-_PROJECT_ROOT = Path(__file__).resolve().parent.parent.parent
-
-
-@given('the pyproject.toml file exists at "{path}"')
-def step_pyproject_exists(context: Context, path: str) -> None:
-    """Verify pyproject.toml exists at the given path."""
-    # Resolve relative paths against the project root so the step works
-    # regardless of the process working directory (e.g. inside parallel workers).
-    resolved = Path(path) if Path(path).is_absolute() else _PROJECT_ROOT / path
-    assert resolved.exists(), f"pyproject.toml not found at {resolved}"
-    context.pyproject_path = resolved
-
-
-@when("I read the project dependencies from pyproject.toml")
-def step_read_project_dependencies(context: Context) -> None:
-    """Read the [project.dependencies] list from pyproject.toml."""
-    content = context.pyproject_path.read_bytes()
-    data: dict[str, Any] = _load_toml(content)
-    context.project_dependencies = data.get("project", {}).get("dependencies", [])
-
 
 @then('the dependency list should include a package matching "{pattern}"')
 def step_dependency_matches_pattern(context: Context, pattern: str) -> None:
@@ -85,24 +65,6 @@ def step_pyyaml_minimum_version(context: Context, expected: str) -> None:
     )
 
 
-@when('I attempt to import the "{module_name}" module')
-def step_attempt_import(context: Context, module_name: str) -> None:
-    """Attempt to import the given module and record the result."""
-    try:
-        context.imported_module = importlib.import_module(module_name)
-        context.import_error = None
-    except ImportError as exc:
-        context.imported_module = None
-        context.import_error = exc
-
-
-@then("the import should succeed without errors")
-def step_import_succeeded(context: Context) -> None:
-    """Assert that the previous import attempt succeeded."""
-    assert context.import_error is None, f"Import failed with: {context.import_error}"
-    assert context.imported_module is not None, "Module was not imported"
-
-
 def _flatten_toml_dict(d: dict[Any, Any]) -> dict[str, Any]:
     """Recursively convert a tomlkit dict to a plain Python dict.