+ ##
+ # work round minitest insanity that causes it to tell you
+ # to use assert_nil to test for nil, which is fine if you're
+ # comparing to a nil constant but not if you're comparing
+ # an expression that might be nil sometimes
+ def assert_equal_allowing_nil(exp, act, msg = nil)
+ if exp.nil?
+ assert_nil act, msg
+ else
+ assert_equal exp, act, msg
+ end
+ end
+