dev/core#193: Ensure that tax amount is calculated when checking for order API line item

[omarabuhussein]

The PR Replaces the following :

• dev/core#193: Ensure that tax amount is calculated when checking for order API line items #12372
• dev/core#193: Ensure that tax amount is calculated when checking for order API line items #12584

Overview

When creating an Order using Order API a check is done to compare Contribution's total_amount against the sum of line item's line_total's. If Contribution total amount and Line Items' total are not equal, Order creation will fail.

Before

As we know:

The line item line_total do not include any tax. Tax will be recorded separately in line item tax_amount field.
The contribution total_amount do include tax. A separate contribution tax_amount field also records the amount of tax.

Since the validation only compares the sum of line_totals with contribution total_amount, whenever there is tax, the validation will fail.

For illustration consider following data set that should create 1 contribution with 2 line items for memberships.

order_data =
{
    'is_pay_later': True,
    'contact_id': 240L,
    'payment_instrument_id': 6,
    'line_items': [{
                       'line_item': {
                           '42': {
                               'price_field_value_id': 60L,
                               'price_field_id': 36L,
                               'entity_id': 1249L,
                               'tax_amount': 2.0,
                               'line_total': 10.0,
                               'financial_type_id': 2,
                               'label': 'General',
                               'entity_table': 'civicrm_membership',
                               'unit_price': 10,
                               'qty': '1'}}}, {
                       'line_item': {
                           '43': {
                               'price_field_value_id': 61L,
                               'price_field_id': 37L,
                               'entity_id': 1248L,
                               'tax_amount': 1.67,
                               'line_total': 8.33,
                               'financial_type_id': 2,
                               'label': 'Concession',
                               'entity_table': 'civicrm_membership',
                               'unit_price': '8.33',
                               'qty': '1'}}}],
    'tax_amount': 3.67,
    'total_amount': 22.0,
    'contribution_recur_id': 605L,
    'financial_type_id': 2,
    'fee_amount': 0,
    'payment_processor_id': 5L,
    'receive_date': u'2019-08-01',
    'contribution_status_id': 2}

Currently Calling the Order API to create Order with the above data results with "Line item total doesn't match with total amount". This is because total_amount (22.0) <> sum of line_totals (18.33)

After

The Line Items check now consider tax_amounts of line_items and order API works fine with the parameters above.

[civibot]

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[seamuslee001]

ping @eileenmcnaughton @JoeMurray

[eileenmcnaughton]

test this please

[monishdeb]

Merging on basis of:

• (r-explain) PASS
• (r-test) PASS (It would be better if we have decimal amounts instead of whole numbers but its ok, will change it in another PR)
• (r-code) PASS
• (r-doc) PASS
• (r-maint) PASS
• (r-run) PASS
• (r-user) PASS
• (r-tech) PASS

[omarabuhussein]

thanks everyone