Before version 3.1.3 removing an unexisting container was throwing an NotFoundException with a message, example: {"message":"No such container: abcdefgh1234567890"}.

Since version 3.1.3, the message of the NotFoundException is null.

This issue is preventing to upgrade from version 3.1.2 to 3.1.3 in bmuschko/gradle-docker-plugin, see failing tests of PR bmuschko/gradle-docker-plugin#840

This is the commit causing the issue: 32b4db6