title: NoMethodError: undefined method `assert_true'
body: <pre><code>NoMethodError: undefined method `assert_true'
  </code></pre>
  
  <p>Am getting above error while running tests using test-unit in ruby. test-unit gem and rake versions are below,</p>
  
  <pre><code>test-unit (2.5.5)
  rake (10.1.0)
  </code></pre>
  
  <p>Sample test file:-</p>
  
  <pre><code>require 'test/unit'
  
  class Sample &lt; Test::Unit::TestCase
  
    def setup
      # code block
    end
  
    def test_sample
      assert_true("test"=="test")
    end
  
    def teardown
      # code block
    end
  
  end
  </code></pre>
  
  <p>How to solve this ?</p>