and corresponding testing_env.rb.
* recast HOMEBREW_BREW_FILE as Hbc.homebrew_executable,
defined in Hbc::Locations
* recast HOMEBREW_REPOSITORY as Hbc.homebrew_repository
* recast HOMEBREW_PREFIX as Hbc.homebrew_prefix
* remove HOMEBREW_LIBRARY
* recast existing Hbc.tapspath as Hbc.homebrew_tapspath
to match new methods
fixes#8705
Just getting started of course, but this piggy backs on Homebrew's
testing strategy to give us a platform for a fully featured test suite.
Neato!
And the tests provide value right away, as I added some better error
handling to `Cask.load`.
Big things ahead. Just you wait.