describe_bug.rb

require "minitest/spec"

MiniTest::Unit.autorun

module DescribeBug
  class Foo
    def ==(other)
      other.is_a? Foo
    end
  end
end

module DescribeBug
  describe Foo do
    before do
      @foo = Foo.new
    end

    # this describe block gets blown away...
    describe '#==' do
      it 'is equal to itself' do
        assert @foo == @foo
      end
    end
    
    # ...by this one
    describe "#<=>" do
      it "compares equally to itself" do
        assert (@foo <=> @foo) == 0
      end
    end
  end

end

This bug exists in the version of minitest in ruby's stdlib, but not in recent versions of the gem:

$ ruby describe_bug.rb 
"1.6.0"
Loaded suite describe_bug
Started
.
Finished in 0.000619 seconds.

1 tests, 1 assertions, 0 failures, 0 errors, 0 skips

Test run options: --seed 18185

$ ruby -I. -e "gem 'minitest' ; require 'describe_bug' "
"2.1.0"
Run options: --seed 40395

# Running tests:

..

Finished tests in 0.000965s, 2073.3553 tests/s, 2073.3553 assertions/s.

2 tests, 2 assertions, 0 failures, 0 errors, 0 skips

Instead of the weird command line I used, you can get the same effect by putting "gem 'minitest'" above any minitest requires.