Auto merge of #4095 - flip1995:mscn_test, r=phansch
Auto merge of #4095 - flip1995:mscn_test, r=phansch

Add test for #3198

Closes #3198

changelog: none

graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust