test(pytest-plugin): add plugin tests

Cover validate_text assertions, fixture factories, marker registration,
and pytest integration using pytester for subprocess testing.

tests/test_pytest_plugin/conftest.py

@@ -0,0 +1,32 @@
+"""Pytest configuration for pytest_plugin tests."""
+
+import pytest
+
+from veritext.pytest_plugin.fixtures import ValidatorFactory
+
+# Enable the pytester fixture for plugin testing
+pytest_plugins = ["pytester"]
+
+# Re-export fixtures from the plugin module for testing
+
+
+@pytest.fixture
+def text_validator() -> ValidatorFactory:
+    """Provide a factory for building validators."""
+    return ValidatorFactory()
+
+
+@pytest.fixture
+def validation_context() -> type:
+    """Provide a factory for creating ValidationContext objects."""
+    from typing import Any
+
+    from veritext.core.types import ValidationContext
+
+    def _create(
+        reference: str | list[str] | None = None,
+        **metadata: Any,
+    ) -> ValidationContext:
+        return ValidationContext(reference=reference, metadata=metadata)
+
+    return _create