""" Property-based tests for missed payments service. These tests verify the correctness properties for missed payment tracking and reporting. """ from hypothesis import given, strategies as st, settings, assume from django.test import TestCase from django.utils import timezone from datetime import date, datetime, timedelta from decimal import Decimal import uuid from loans.models import Loan, LoanProduct, LoanApplication from users.models import CustomUser from reports.missed_payments_service import MissedPaymentsService # Custom strategies for generating test data @st.composite def client_with_loans_strategy(draw): """Generate a client with multiple loans, some with missed payments""" # Create client username = f"test_user_{uuid.uuid4().hex[:8]}" client = CustomUser.objects.create_user( username=username, email=f"{username}@example.com", phone_number=f"+2547{draw(st.integers(min_value=10000000, max_value=99999999))}", first_name='Test', last_name='User' ) # Create loan product product = LoanProduct.objects.create( name=f'Test Product {uuid.uuid4().hex[:8]}', product_type='boost', description='Test product', min_amount=Decimal('1000'), max_amount=Decimal('50000'), interest_rate=Decimal('10.0'), processing_fee=Decimal('5.0'), min_duration=7, max_duration=90, available_repayment_methods=['monthly'] ) return client, product class TestMissedPaymentDetailRetrieval(TestCase): """ Test Property 26: Missed payment detail retrieval Feature: reports-system-enhancement, Property 26: Missed payment detail retrieval Validates: Requirements 10.2 For any client in the missed payments report, clicking "View All Missed Payments" should display all loans for that client where due_date < current_date AND outstanding_amount > 0. """ @settings(max_examples=50, deadline=None) @given( num_overdue_loans=st.integers(min_value=1, max_value=5), num_current_loans=st.integers(min_value=0, max_value=3), days_overdue=st.integers(min_value=1, max_value=90) ) def test_missed_payment_detail_includes_all_overdue_loans( self, num_overdue_loans, num_current_loans, days_overdue ): """ Property: For any client, get_missed_payments_for_client should return all loans where due_date < today AND outstanding_amount > 0. """ # Create client and product username = f"test_user_{uuid.uuid4().hex[:8]}" client = CustomUser.objects.create_user( username=username, email=f"{username}@example.com", phone_number=f"+254700000000", first_name='Test', last_name='User' ) product = LoanProduct.objects.create( name=f'Test Product {uuid.uuid4().hex[:8]}', product_type='boost', description='Test product', min_amount=Decimal('1000'), max_amount=Decimal('50000'), interest_rate=Decimal('10.0'), processing_fee=Decimal('5.0'), min_duration=7, max_duration=90, available_repayment_methods=['monthly'] ) today = timezone.now().date() # Create overdue loans (should be included) overdue_loan_ids = [] for i in range(num_overdue_loans): application = LoanApplication.objects.create( borrower=client, loan_product=product, requested_amount=Decimal('10000'), requested_duration=30, purpose='Test', status='approved' ) due_date = today - timedelta(days=days_overdue) loan = Loan.objects.create( application=application, borrower=client, principal_amount=Decimal('10000'), interest_amount=Decimal('1000'), processing_fee=Decimal('500'), total_amount=Decimal('11500'), disbursement_date=due_date - timedelta(days=30), due_date=due_date, duration_days=30, status='active', is_deleted=False, is_rolled_over=False ) overdue_loan_ids.append(str(loan.id)) # Create current loans (should NOT be included) for i in range(num_current_loans): application = LoanApplication.objects.create( borrower=client, loan_product=product, requested_amount=Decimal('10000'), requested_duration=30, purpose='Test', status='approved' ) due_date = today + timedelta(days=30) Loan.objects.create( application=application, borrower=client, principal_amount=Decimal('10000'), interest_amount=Decimal('1000'), processing_fee=Decimal('500'), total_amount=Decimal('11500'), disbursement_date=today, due_date=due_date, duration_days=30, status='active', is_deleted=False, is_rolled_over=False ) # Get missed payments for client missed_payments = MissedPaymentsService.get_missed_payments_for_client(str(client.id)) # Verify: Should return exactly the overdue loans self.assertEqual(len(missed_payments), num_overdue_loans) # Verify: All returned loans should be overdue for payment in missed_payments: self.assertLess(payment['due_date'], today) self.assertGreater(payment['amount_due'], 0) # Verify: All overdue loans should be in the results returned_loan_ids = [str(payment['loan'].id) for payment in missed_payments] for loan_id in overdue_loan_ids: self.assertIn(loan_id, returned_loan_ids) class TestMissedPaymentDefinition(TestCase): """ Test Property 27: Missed payment definition Feature: reports-system-enhancement, Property 27: Missed payment definition Validates: Requirements 10.4 For any loan, it should be classified as having a missed payment if and only if due_date < current_date AND outstanding_amount > 0. """ @settings(max_examples=50, deadline=None) @given( days_offset=st.integers(min_value=-90, max_value=90), has_outstanding=st.booleans() ) def test_missed_payment_definition_correctness(self, days_offset, has_outstanding): """ Property: A loan has a missed payment IFF due_date < today AND outstanding > 0. """ # Create client and product username = f"test_user_{uuid.uuid4().hex[:8]}" client = CustomUser.objects.create_user( username=username, email=f"{username}@example.com", phone_number=f"+254700000000", first_name='Test', last_name='User' ) product = LoanProduct.objects.create( name=f'Test Product {uuid.uuid4().hex[:8]}', product_type='boost', description='Test product', min_amount=Decimal('1000'), max_amount=Decimal('50000'), interest_rate=Decimal('10.0'), processing_fee=Decimal('5.0'), min_duration=7, max_duration=90, available_repayment_methods=['monthly'] ) today = timezone.now().date() due_date = today + timedelta(days=days_offset) # Create loan application application = LoanApplication.objects.create( borrower=client, loan_product=product, requested_amount=Decimal('10000'), requested_duration=30, purpose='Test', status='approved' ) # Create loan with specified due date loan = Loan.objects.create( application=application, borrower=client, principal_amount=Decimal('10000'), interest_amount=Decimal('1000'), processing_fee=Decimal('500'), total_amount=Decimal('11500'), disbursement_date=due_date - timedelta(days=30), due_date=due_date, duration_days=30, status='active', is_deleted=False, is_rolled_over=False ) # Set outstanding amount based on has_outstanding if not has_outstanding: # Simulate full payment by setting _amount_paid_cache loan._amount_paid_cache = loan.total_amount loan.save() # Get missed payments for client missed_payments = MissedPaymentsService.get_missed_payments_for_client(str(client.id)) # Determine expected result is_overdue = due_date < today has_outstanding_balance = loan.outstanding_amount > 0 should_be_missed = is_overdue and has_outstanding_balance # Verify: Loan should be in missed payments IFF it meets both conditions loan_in_results = any(str(p['loan'].id) == str(loan.id) for p in missed_payments) self.assertEqual(loan_in_results, should_be_missed) class TestMissedPaymentsSortOrder(TestCase): """ Test Property 28: Missed payments sort order Feature: reports-system-enhancement, Property 28: Missed payments sort order Validates: Requirements 10.5 For any list of missed payments, the records should be ordered by due_date in descending order (most recent first). """ @settings(max_examples=50, deadline=None) @given( num_loans=st.integers(min_value=2, max_value=10) ) def test_missed_payments_sorted_by_due_date_descending(self, num_loans): """ Property: For any client with multiple missed payments, the results should be sorted by due_date in descending order. """ # Create client and product username = f"test_user_{uuid.uuid4().hex[:8]}" client = CustomUser.objects.create_user( username=username, email=f"{username}@example.com", phone_number=f"+254700000000", first_name='Test', last_name='User' ) product = LoanProduct.objects.create( name=f'Test Product {uuid.uuid4().hex[:8]}', product_type='boost', description='Test product', min_amount=Decimal('1000'), max_amount=Decimal('50000'), interest_rate=Decimal('10.0'), processing_fee=Decimal('5.0'), min_duration=7, max_duration=90, available_repayment_methods=['monthly'] ) today = timezone.now().date() # Create loans with different due dates (all overdue) due_dates = [] for i in range(num_loans): days_overdue = (i + 1) * 10 # 10, 20, 30, ... days overdue due_date = today - timedelta(days=days_overdue) due_dates.append(due_date) application = LoanApplication.objects.create( borrower=client, loan_product=product, requested_amount=Decimal('10000'), requested_duration=30, purpose='Test', status='approved' ) Loan.objects.create( application=application, borrower=client, principal_amount=Decimal('10000'), interest_amount=Decimal('1000'), processing_fee=Decimal('500'), total_amount=Decimal('11500'), disbursement_date=due_date - timedelta(days=30), due_date=due_date, duration_days=30, status='active', is_deleted=False, is_rolled_over=False ) # Get missed payments for client missed_payments = MissedPaymentsService.get_missed_payments_for_client(str(client.id)) # Verify: Should return all loans self.assertEqual(len(missed_payments), num_loans) # Verify: Results should be sorted by due_date descending (most recent first) for i in range(len(missed_payments) - 1): current_due_date = missed_payments[i]['due_date'] next_due_date = missed_payments[i + 1]['due_date'] self.assertGreaterEqual(current_due_date, next_due_date, f"Missed payments not sorted correctly: {current_due_date} should be >= {next_due_date}")