This test suite is based on the Web Map Server Implementation Specification, version 1.1.1 [OGC 01-068r3](PDF version, HTML version)
The Test Requirements and Assertions for WMS 1.1.1 document provides detailed information about this test.
WMS 1.1 Reference Implementations are listed here: https://github.com/opengeospatial/cite/wiki/Reference-Implementations
Release notes are available here.