[test] allow multiple tests in TEST= when executing Rails tests

This helps debugging stuff that only fails when run in combination.

Author: dr-itz

rakelib/rails.rake

@@ -51,7 +51,7 @@ namespace :rails do
       ruby_opts_string += " -C \"#{ar_path}\""
       ruby_opts_string += " -rbundler/setup"
       ruby_opts_string += " -rminitest -rminitest/excludes" unless ENV['NO_EXCLUDES'].eql?('true')
-      file_list = ENV["TEST"] ? FileList[ ENV["TEST"] ] : test_files_finder.call
+      file_list = ENV["TEST"] ? FileList[ ENV["TEST"].split(',') ] : test_files_finder.call
       file_list_string = file_list.map { |fn| "\"#{fn}\"" }.join(' ')
       # test_loader_code = "-e \"ARGV.each{|f| require f}\"" # :direct
       option_list = ( ENV["TESTOPTS"] || ENV["TESTOPT"] || ENV["TEST_OPTS"] || '' )