I hope I made the right choice here,

SiteTree seemed to have a lot of various tests broken down by subject (SiteTreePermissionsTest, SiteTreeHTMLEditorFieldTest, SiteTreeBacklinksTest, etc....) so I felt it would be best to group the "like" CMSField tests together.

The other reason is that SiteTreeTest is already a behemoth, and it makes repeated tests harder when lots of unrelated tests have to be run each time something is tweaked..

I also had to create a lot of extra data classes that had no revelance to other SiteTree tests, so I opted to avoid trying to either make them into multipurpose testing classes, or mix them with yet another set of class definitions.