Fix for issue #5105 - Error While send Invoice with Grouped Products

[michielgerritsen]

This is a fix for issue #5105.

Description

When the merchant tried to send the invoice to the customer, it could get an fatal error. This only happend when the order contained grouped products. This was caused by the fact that DefaultOrder::getItemPrice has an type hint for the OrderItem, but the InvoiceItem was passed. I fixed this by requesting the OrderItem from the InvoiceItem.

Fixed Issues (if relevant)

1. Error While send Invoice with Grouped Products #5105: Error While send Invoice with Grouped Products

Manual testing scenarios

1. Install the sample data.
2. Order the Set of Sprite Yoga Straps.
3. Create an invoice.
4. Open the invoice and click Send e-mail.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[michielgerritsen]

The Travis tests are failing, but i've check the mark:

• The unit test fails no matter if i add my code or not. It is a test for the ObjectManager, it seems unrelated.
• The acceptance test fails due to not having output for too long.

[okorshenko]

Hi @michielgerritsen Could you please accept the invitation on GitHub?

[michielgerritsen]

Hi @okorshenko Check, done. Thanks for the invitation :-)