Add Rake's test loader because it is inconsistently installed.

test/loader.rb

@@ -0,0 +1,44 @@
+# Yoinked lovingly from Rake's source code.
+#
+# Copyright (c) Jim Weirich
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+require 'rake'
+
+# Load the test files from the command line.
+argv = ARGV.select do |argument|
+  case argument
+  when /^-/ then
+    argument
+  when /\*/ then
+    FileList[argument].to_a.each do |file|
+      require File.expand_path file
+    end
+
+    false
+  else
+    require File.expand_path argument
+
+    false
+  end
+end
+
+ARGV.replace argv