Added support for minitest under Ruby 1.9.

src/edgecase.rb

@@ -46,7 +46,13 @@ module EdgeCase
   class Sensei
     attr_reader :failure, :failed_test
 
-    AssertionError = Test::Unit::AssertionFailedError
+    in_ruby_version("1.8") do
+      AssertionError = Test::Unit::AssertionFailedError
+    end
+
+    in_ruby_version("1.9") do
+      AssertionError = MiniTest::Assertion
+    end
 
     def initialize
       @pass_count = 0
@@ -169,12 +175,12 @@ module EdgeCase
         test.setup
         begin
           test.send(method)
-        rescue StandardError => ex
+        rescue StandardError, EdgeCase::Sensei::AssertionError => ex
           test.failed(ex)
         ensure
           begin
             test.teardown
-          rescue StandardError => ex
+          rescue StandardError, EdgeCase::Sensei::AssertionError => ex
             test.failed(ex) if test.passed?
           end
         end