What WMS capabilities DTD does the test suite use?
For WMS 1.1.1 test wms/wmsops/getcapabilities/response/2 in the test suite uses a copy of the DTD which is listed in Annex A.1 of the WMS 1.1.1 spec to verify that the capabilities document references a valid DTD. A copy of this DTD can be found online at http://schemas.opengis.net/wms/1.1.1/WMS_MS_Capabilities.dtd. Note that currently, this differs slightly from the online version mentioned in Annex A (http://www.digitalearth.gov/wmt/xml/capabilities_1_1_1.dtd), so capabilites documents which reference that DTD will fail. WMS 1.3.0 uses an XSD located here: http://schemas.opengis.net/wms/1.3.0/capabilities_1_3_0.xsd.