Update testing documentation and changelog with blocking changes

Author: opr

docs/testing/releases/450.md

@@ -109,3 +109,22 @@ function add_fees( $cart ) {
 ```
 2. Add a product to your cart and visit the Cart or Checkout pages.
 3. Verify the dash is rendered correctly.
+
+### Show cart item total price including taxes when DISPLAY_CART_PRICES_INCLUDING_TAX is true ([3851](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/3851))
+In wp-admin:
+1. Go to WooCommerce > Settings and check the option `Enable tax rates and calculations `.
+2. Go to WooCommerce > Settings > Tax and set `Prices entered with tax` to `No, I will enter prices exclusive of tax` and `Display prices during cart and checkout` to `Including tax`.
+3. Go to WooCommerce > Settings > Tax > Standard Rates and create a tax rate for a specific country.
+
+In the frontend:
+1. Add a product to your cart and go to the Cart or Checkout blocks.
+2. Verify the product unitary price and the cart line total show the price including taxes:
+
+| Before | After |
+| --- | --- |
+| ![imatge](https://user-images.githubusercontent.com/3616980/108037796-5ddb4f80-703a-11eb-9656-cac05a57b8c5.png) | ![imatge](https://user-images.githubusercontent.com/3616980/108038392-10abad80-703b-11eb-8c96-52e1c0f2341f.png) |
+
+### Fix product price not displaying properly when product is on sale ([3853](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/3853))
+
+1. Set a product to be on sale and add it to the cart
+2. Go to the cart and checkout blocks and make sure you can see the struckthrough regular price, and the sale price is displayed normally.

readme.txt

@@ -103,6 +103,7 @@ Release and roadmap notes available on the [WooCommerce Developers Blog](https:/
 - Fix JS warning if two cart products share the same name. ([3814](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/3814))
 - Align place order button to the right of the block. ([3803](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/3803))
 - Ensure special characters are displayed properly in the Cart sidebar. ([3721](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/3721))
+- Fix a bug where the total price of items did not include tax in the cart and checkout blocks. ([3851](https://github.com/woocommerce/woocommerce-gutenberg-products-block/pull/3851))
 
 #### Documentation