The Lucene and Solr components has several issues which makes it untestable and unusable as a single plugin. I'm not even sure if this should be a bug or improvement issue.
There are several file and data dependencies left which should be (re-)moved.
The file runtime/indexes/index.properties should be moved to the solr component. The folder runtime/indexes should be removed, the components have to take care of creating their index path(s).
This issue might receive some subtasks along this journey...