It runs more than one method when names start equals

When have two methos that start similar and only change the end, then run the two methods.

Example:

test.rb file
````
require 'minitest/autorun'

Ruler = Struct.new(:rule)

class RulerTest < MiniTest::Unit::TestCase
  def test_rule  # line 6
    assert_equal 'rule', Ruler.new('rule').rule   
  end

  def test_rule_empty # line 10
    assert_equal '', Ruler.new('').rule
  end
end
````

When run line 10 that work as expected (run the method _test_rule_empty_)

````
Run options: -n "/(test_rule_empty)/" --seed 45258

# Running tests:

.

Finished tests in 0.000435s, 2297.9895 tests/s, 2297.9895 assertions/s.

1 tests, 1 assertions, 0 failures, 0 errors, 0 skips
````

But, when run line 6

````
m test.rb:6

Run options: -n "/(test_rule)/" --seed 49816

# Running tests:

..

Finished tests in 0.000508s, 3935.8690 tests/s, 3935.8690 assertions/s.

2 tests, 2 assertions, 0 failures, 0 errors, 0 skips
````

Run the two methods.  

Apparently is a problem with the run option "/(test_rule)/"
I think it should be "/^(test_rule)$/"

What do you think?