tests/unit/test_fraud_detection.py

"""
Unit tests for fraud detection algorithms
"""


class TestFraudDetection:
    """Test fraud detection engine"""

    def test_fraud_engine_initialization(self):
        """Test fraud detection engine can be initialized"""
        from app.services.fraud.engine import RuleEngine

        engine = RuleEngine()
        assert engine is not None

    def test_fraud_rule_creation(self):
        """Test creating a basic fraud rule"""

        # Test rule structure
        rule = {
            "name": "Test Rule",
            "description": "Test fraud detection rule",
            "severity": "medium",
            "enabled": True,
            "conditions": [
                {"field": "amount", "operator": "greater_than", "value": 10000}
            ],
        }

        assert rule["name"] == "Test Rule"
        assert rule["severity"] == "medium"

    def test_transaction_analysis(self):
        """Test basic transaction analysis"""
        # Mock transaction data
        transaction = {
            "id": "test-tx-123",
            "amount": 15000,
            "user_id": "user123",
            "timestamp": "2024-01-01T10:00:00Z",
        }

        # Basic validation
        assert transaction["amount"] > 10000
        assert transaction["user_id"] is not None


class TestSecurityValidation:
    """Test security validation functions"""

    def test_password_strength(self):
        """Test password strength validation"""
        # This would test password validation logic
        # For now, just check basic requirements
        weak_passwords = ["123", "password", "abc"]
        strong_password = "ComplexP@ssw0rd123!"

        for weak in weak_passwords:
            assert len(weak) <= 8, f"Password '{weak}' should be considered weak"

        assert len(strong_password) >= 12

    def test_input_sanitization(self):
        """Test input sanitization"""
        dangerous_inputs = [
            "<script>alert('xss')</script>",
            "'; DROP TABLE users; --",
            "../../../etc/passwd",
        ]

        for dangerous in dangerous_inputs:
            # Check for potentially dangerous characters
            assert "<" in dangerous or ";" in dangerous or ".." in dangerous


class TestDataValidation:
    """Test data validation functions"""

    def test_email_validation(self):
        """Test email format validation"""
        valid_emails = [
            "user@example.com",
            "test.email+tag@domain.co.uk",
            "user@localhost",
        ]

        invalid_emails = ["invalid", "@domain.com", "user@", "user.domain.com"]

        for email in valid_emails:
            assert "@" in email
            if email != "user@localhost":
                assert "." in email

        for email in invalid_emails:
            parts = email.split("@")
            # Invalid if not exactly one @, or if either side is empty
            assert len(parts) != 2 or not parts[0] or not parts[1]

    def test_amount_validation(self):
        """Test monetary amount validation"""
        valid_amounts = [0.01, 100.00, 999999.99]
        invalid_amounts = [-100, 0, 1000000]

        for amount in valid_amounts:
            assert amount > 0
            assert amount < 1000000

        for amount in invalid_amounts:
            assert amount <= 0 or amount >= 1000000