vendor_bill_editable_totals/tests/test_price_subtotal_property.py

# -*- coding: utf-8 -*-
# Part of Odoo. See LICENSE file for full copyright and licensing details.

from odoo.tests import TransactionCase
from hypothesis import given, settings, strategies as st
from decimal import Decimal


class TestPriceSubtotalProperty(TransactionCase):
    """
    Property-based tests for price_subtotal calculation.
    
    **Feature: vendor-bill-editable-totals, Property 1: Price subtotal to unit price calculation**
    """

    def setUp(self):
        super().setUp()
        
        # Create a vendor partner
        self.vendor = self.env['res.partner'].create({
            'name': 'Test Vendor',
            'supplier_rank': 1,
        })
        
        # Create a product
        self.product = self.env['res.product'].create({
            'name': 'Test Product',
            'type': 'service',
            'list_price': 100.0,
        })
        
        # Create a vendor bill
        self.vendor_bill = self.env['account.move'].create({
            'move_type': 'in_invoice',
            'partner_id': self.vendor.id,
            'invoice_date': '2024-01-01',
        })
        
        # Get decimal precision for Product Price
        self.precision = self.env['decimal.precision'].precision_get('Product Price')

    @given(
        price_subtotal=st.floats(min_value=0.01, max_value=1000000.0, allow_nan=False, allow_infinity=False),
        quantity=st.floats(min_value=1.0, max_value=10000.0, allow_nan=False, allow_infinity=False)
    )
    @settings(max_examples=100, deadline=None)
    def test_property_price_subtotal_to_unit_price(self, price_subtotal, quantity):
        """
        **Feature: vendor-bill-editable-totals, Property 1: Price subtotal to unit price calculation**
        **Validates: Requirements 1.2, 1.4**
        
        Property: For any invoice line with non-zero quantity and a user-modified 
        price_subtotal value, the recalculated price_unit should equal price_subtotal 
        divided by quantity.
        """
        # Create an invoice line
        line = self.env['account.move.line'].create({
            'move_id': self.vendor_bill.id,
            'product_id': self.product.id,
            'name': 'Test Line',
            'quantity': quantity,
            'price_unit': 1.0,  # Initial value, will be recalculated
        })
        
        # Set the price_subtotal to trigger the onchange
        line.price_subtotal = price_subtotal
        line._onchange_price_subtotal()
        
        # Calculate expected price_unit
        expected_price_unit = price_subtotal / quantity
        expected_price_unit_rounded = round(expected_price_unit, self.precision)
        
        # Verify the property: price_unit should equal price_subtotal / quantity
        self.assertAlmostEqual(
            line.price_unit,
            expected_price_unit_rounded,
            places=self.precision,
            msg=f"Price unit calculation failed: expected {expected_price_unit_rounded}, got {line.price_unit}"
        )

    @given(
        price_subtotal=st.floats(min_value=0.01, max_value=1000000.0, allow_nan=False, allow_infinity=False),
        quantity=st.floats(min_value=1.0, max_value=10000.0, allow_nan=False, allow_infinity=False)
    )
    @settings(max_examples=100, deadline=None)
    def test_property_quantity_invariance(self, price_subtotal, quantity):
        """
        **Feature: vendor-bill-editable-totals, Property 2: Quantity invariance during price_subtotal modification**
        **Validates: Requirements 1.3**
        
        Property: For any invoice line, when price_subtotal is modified, the quantity 
        value should remain unchanged after the onchange handler executes.
        """
        # Create an invoice line
        line = self.env['account.move.line'].create({
            'move_id': self.vendor_bill.id,
            'product_id': self.product.id,
            'name': 'Test Line',
            'quantity': quantity,
            'price_unit': 1.0,  # Initial value, will be recalculated
        })
        
        # Store the initial quantity
        initial_quantity = line.quantity
        
        # Set the price_subtotal to trigger the onchange
        line.price_subtotal = price_subtotal
        line._onchange_price_subtotal()
        
        # Verify the property: quantity should remain unchanged
        self.assertEqual(
            line.quantity,
            initial_quantity,
            msg=f"Quantity changed during price_subtotal modification: expected {initial_quantity}, got {line.quantity}"
        )

    @given(
        price_subtotal=st.floats(min_value=0.01, max_value=1000000.0, allow_nan=False, allow_infinity=False),
        quantity=st.floats(min_value=1.0, max_value=10000.0, allow_nan=False, allow_infinity=False)
    )
    @settings(max_examples=100, deadline=None)
    def test_property_price_subtotal_round_trip(self, price_subtotal, quantity):
        """
        **Feature: vendor-bill-editable-totals, Property 3: Price subtotal round-trip accuracy**
        **Validates: Requirements 1.5**
        
        Property: For any invoice line with non-zero quantity, if a user inputs a 
        price_subtotal value, the system calculates price_unit, and then Odoo recomputes 
        price_subtotal from that price_unit and quantity, the final price_subtotal should 
        match the user input within the configured decimal precision.
        """
        # Create an invoice line
        line = self.env['account.move.line'].create({
            'move_id': self.vendor_bill.id,
            'product_id': self.product.id,
            'name': 'Test Line',
            'quantity': quantity,
            'price_unit': 1.0,  # Initial value, will be recalculated
        })
        
        # Store the user input price_subtotal
        user_input_subtotal = price_subtotal
        
        # Step 1: Set the price_subtotal to trigger the onchange
        line.price_subtotal = user_input_subtotal
        line._onchange_price_subtotal()
        
        # Step 2: Let Odoo recompute price_subtotal from price_unit and quantity
        # This simulates what happens when Odoo's standard compute methods run
        recomputed_subtotal = line.price_unit * line.quantity
        
        # Calculate the tolerance based on decimal precision
        # We allow a small discrepancy due to rounding
        tolerance = 10 ** (-self.precision)
        
        # Verify the property: recomputed price_subtotal should match user input
        # within the configured decimal precision
        self.assertAlmostEqual(
            recomputed_subtotal,
            user_input_subtotal,
            places=self.precision,
            msg=f"Round-trip accuracy failed: user input={user_input_subtotal:.{self.precision}f}, "
                f"price_unit={line.price_unit:.{self.precision}f}, "
                f"recomputed={recomputed_subtotal:.{self.precision}f}, "
                f"difference={abs(recomputed_subtotal - user_input_subtotal):.{self.precision+2}f}"
        )