WIP

tests/domain/test_invoice_validator.py

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+"""
+Tests for InvoiceValidator - TDD RED phase.
+
+Test invoice field validation logic.
+"""
+import pytest
+
+from backend.domain.invoice_validator import (
+    InvoiceValidator,
+    ValidationResult,
+    ValidationIssue,
+)
+
+
+class TestInvoiceValidator:
+    """Test invoice validation logic."""
+
+    @pytest.fixture
+    def validator(self) -> InvoiceValidator:
+        """Create validator instance with default settings."""
+        return InvoiceValidator()
+
+    @pytest.fixture
+    def validator_strict(self) -> InvoiceValidator:
+        """Create validator with strict confidence threshold."""
+        return InvoiceValidator(min_confidence=0.8)
+
+    # ==================== Valid Invoice Tests ====================
+
+    def test_validate_complete_invoice_is_valid(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """Complete invoice with all required fields is valid."""
+        fields = {
+            "Amount": "1200.00",
+            "OCR": "123456789012",
+            "Bankgiro": "123-4567",
+        }
+        confidence = {
+            "Amount": 0.95,
+            "OCR": 0.90,
+            "Bankgiro": 0.85,
+        }
+
+        result = validator.validate(fields, confidence)
+
+        assert result.is_valid is True
+        assert len([i for i in result.issues if i.severity == "error"]) == 0
+
+    def test_validate_invoice_with_payment_line_is_valid(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """Invoice with payment_line as payment reference is valid."""
+        fields = {
+            "Amount": "500.00",
+            "payment_line": "# 123 # 500 00 5 > 308#",
+        }
+        confidence = {"Amount": 0.9, "payment_line": 0.85}
+
+        result = validator.validate(fields, confidence)
+
+        assert result.is_valid is True
+
+    # ==================== Invalid Invoice Tests ====================
+
+    def test_validate_missing_amount_is_invalid(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """Missing Amount field should produce error."""
+        fields = {
+            "OCR": "123456789012",
+            "Bankgiro": "123-4567",
+        }
+        confidence = {"OCR": 0.9, "Bankgiro": 0.85}
+
+        result = validator.validate(fields, confidence)
+
+        assert result.is_valid is False
+        error_fields = [i.field for i in result.issues if i.severity == "error"]
+        assert "Amount" in error_fields
+
+    def test_validate_missing_payment_reference_produces_warning(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """Missing all payment references should produce warning."""
+        fields = {"Amount": "1200.00"}
+        confidence = {"Amount": 0.9}
+
+        result = validator.validate(fields, confidence)
+
+        # Missing payment ref is warning, not error
+        warning_fields = [i.field for i in result.issues if i.severity == "warning"]
+        assert "payment_reference" in warning_fields
+
+    # ==================== Confidence Threshold Tests ====================
+
+    def test_validate_low_confidence_produces_warning(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """Fields below confidence threshold should produce warning."""
+        fields = {
+            "Amount": "1200.00",
+            "OCR": "123456789012",
+        }
+        confidence = {
+            "Amount": 0.9,
+            "OCR": 0.3,  # Below default threshold of 0.5
+        }
+
+        result = validator.validate(fields, confidence)
+
+        low_conf_warnings = [
+            i for i in result.issues
+            if i.severity == "warning" and "confidence" in i.message.lower()
+        ]
+        assert len(low_conf_warnings) > 0
+
+    def test_validate_strict_threshold_more_warnings(
+        self, validator_strict: InvoiceValidator
+    ) -> None:
+        """Strict validator should produce more warnings."""
+        fields = {
+            "Amount": "1200.00",
+            "OCR": "123456789012",
+        }
+        confidence = {
+            "Amount": 0.7,  # Below 0.8 threshold
+            "OCR": 0.6,  # Below 0.8 threshold
+        }
+
+        result = validator_strict.validate(fields, confidence)
+
+        low_conf_warnings = [
+            i for i in result.issues
+            if i.severity == "warning" and "confidence" in i.message.lower()
+        ]
+        assert len(low_conf_warnings) >= 2
+
+    # ==================== Edge Cases ====================
+
+    def test_validate_empty_fields_is_invalid(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """Empty fields dict should be invalid."""
+        fields: dict[str, str | None] = {}
+        confidence: dict[str, float] = {}
+
+        result = validator.validate(fields, confidence)
+
+        assert result.is_valid is False
+
+    def test_validate_none_field_values_treated_as_missing(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """None values should be treated as missing."""
+        fields = {
+            "Amount": None,
+            "OCR": "123456789012",
+        }
+        confidence = {"OCR": 0.9}
+
+        result = validator.validate(fields, confidence)
+
+        assert result.is_valid is False
+        error_fields = [i.field for i in result.issues if i.severity == "error"]
+        assert "Amount" in error_fields
+
+    def test_validate_empty_string_treated_as_missing(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """Empty string should be treated as missing."""
+        fields = {
+            "Amount": "",
+            "OCR": "123456789012",
+        }
+        confidence = {"OCR": 0.9}
+
+        result = validator.validate(fields, confidence)
+
+        assert result.is_valid is False
+
+    # ==================== ValidationResult Properties ====================
+
+    def test_validation_result_is_immutable(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """ValidationResult should be a frozen dataclass."""
+        fields = {"Amount": "100.00", "OCR": "123"}
+        confidence = {"Amount": 0.9, "OCR": 0.9}
+        result = validator.validate(fields, confidence)
+
+        with pytest.raises((AttributeError, TypeError)):
+            result.is_valid = False  # type: ignore
+
+    def test_validation_result_issues_is_tuple(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """Issues should be a tuple (immutable)."""
+        fields = {"Amount": "100.00"}
+        confidence = {"Amount": 0.9}
+        result = validator.validate(fields, confidence)
+
+        assert isinstance(result.issues, tuple)
+
+    def test_validation_result_has_confidence(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """ValidationResult should have confidence score."""
+        fields = {"Amount": "100.00", "OCR": "123"}
+        confidence = {"Amount": 0.9, "OCR": 0.8}
+        result = validator.validate(fields, confidence)
+
+        assert hasattr(result, "confidence")
+        assert 0.0 <= result.confidence <= 1.0
+
+    # ==================== ValidationIssue Tests ====================
+
+    def test_validation_issue_has_required_fields(
+        self, validator: InvoiceValidator
+    ) -> None:
+        """ValidationIssue must have field, severity, message."""
+        fields: dict[str, str | None] = {}
+        confidence: dict[str, float] = {}
+        result = validator.validate(fields, confidence)
+
+        assert len(result.issues) > 0
+        issue = result.issues[0]
+
+        assert hasattr(issue, "field")
+        assert hasattr(issue, "severity")
+        assert hasattr(issue, "message")
+        assert issue.severity in ("error", "warning", "info")