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/test_fixtures.py

@@ -0,0 +1,88 @@
+"""Tests for the pytest plugin fixtures."""
+
+from veritext.core.types import ValidationContext
+from veritext.pytest_plugin.fixtures import ValidatorFactory
+from veritext.validators import bleu, length
+
+
+class TestValidatorFactory:
+    """Test the ValidatorFactory class."""
+
+    def test_creates_validator_from_checks(self) -> None:
+        """Test that factory creates a callable validator."""
+        factory = ValidatorFactory()
+        validate = factory(checks=[length(min_chars=5)])
+
+        result = validate("Hello, World!")
+        assert result.passed
+
+    def test_validator_uses_provided_reference(self) -> None:
+        """Test that factory passes reference to context."""
+        factory = ValidatorFactory()
+        reference = "The quick brown fox."
+        validate = factory(
+            checks=[bleu(min_score=0.5)],
+            reference=reference,
+        )
+
+        # Exact match should pass
+        result = validate("The quick brown fox.")
+        assert result.passed
+
+    def test_validator_returns_validation_result(self) -> None:
+        """Test that validator returns a ValidationResult."""
+        factory = ValidatorFactory()
+        validate = factory(checks=[length(min_chars=100)])
+
+        result = validate("Short")
+        assert not result.passed
+        assert len(result.checks) == 1
+        assert result.checks[0].name == "length"
+
+
+class TestTextValidatorFixture:
+    """Test the text_validator fixture."""
+
+    def test_fixture_returns_factory(self, text_validator: ValidatorFactory) -> None:
+        """Test that fixture provides a ValidatorFactory."""
+        assert isinstance(text_validator, ValidatorFactory)
+
+    def test_fixture_can_create_validators(
+        self,
+        text_validator: ValidatorFactory,
+    ) -> None:
+        """Test that fixture can be used to create validators."""
+        validate = text_validator(checks=[length(min_chars=5, max_chars=50)])
+
+        assert validate("Hello, World!").passed
+        assert not validate("Hi").passed
+
+
+class TestValidationContextFixture:
+    """Test the validation_context fixture."""
+
+    def test_fixture_creates_context(
+        self,
+        validation_context: type,
+    ) -> None:
+        """Test that fixture creates ValidationContext."""
+        ctx = validation_context(reference="Test reference")
+        assert isinstance(ctx, ValidationContext)
+        assert ctx.reference == "Test reference"
+
+    def test_fixture_accepts_metadata(
+        self,
+        validation_context: type,
+    ) -> None:
+        """Test that fixture passes metadata to context."""
+        ctx = validation_context(reference="Test", source="unit_test", version=1)
+        assert ctx.metadata["source"] == "unit_test"
+        assert ctx.metadata["version"] == 1
+
+    def test_fixture_allows_no_reference(
+        self,
+        validation_context: type,
+    ) -> None:
+        """Test that fixture allows creating context without reference."""
+        ctx = validation_context()
+        assert ctx.reference is None