Currently we are using Apache Solr 4.10.3 OR Heliosearch Distribution for Solr [HDS] as a search engine to i
You can find your solrconfig.xml and schema.xml inside the collection directory. Go to /usr/lib/ambari-infra-solr/server/solr and u will see a folder with same name as of collection and with schema and config files. Inside the conf folder there will be a managed-schema file and other files that you have been searching for.
As for this error Error CREATEing SolrCore 'testcore1': Unable to create core [testcore1] Caused by: Could not find configName for collection testcore1 found:null This error must be coming when you are creating solr collection from UI. For that go to location where solr.cmd is located and type the below code ./solr create -c -d -s -r