We have experienced some problem while we developing our Wechat Mini Program.
Currently, we are unable to complete the checkout with web checkout. Since Wechat does not allow us to open up a page in webview with un-verified domain iframe (since Shopify Payments, Google and Paypal use iframe in checkout page). Also, we are using Wechat Pay as payment in our Wechat Mini Program, so basically what we need is mark checkout as complete.
Seems like there is only api for completing checkout with Credit Card, and we looking forward to solution to this.
Our current work around is to manual create order when payment started through Admin API. and add transaction to order through Admin API when we receive payment callback. However, this solution may create multiple orders when users make multiple payment attempts.