Gerald Meszaros has defined four phases to be included while structuring unit tests. The four phases are:

• Setup is the first phase where test fixture is setup for the SUT (System under Test) to exhibit the expected behaviour as well as anything we need to put in place to be able to observe the actual outcome
• Interact with the SUT or exercise
• Verify / Determine if expected outcome is obtained
• Tear Down the test fixture

Implementation

Account.rb

class Account
  MIN_BALANCE = 100
  attr_reader :balance

  def initialize
    @balance = MIN_BALANCE
  end
end

account_test.rb

class Account_Test < Test::Unit::TestCase
  def test_there_should_be_minium_balance_when_account_is_created
    #setup
    @account = Account.new
    #exercise
    balance = @account.balance
    #verify
    assert_operator balance, :>, 0
  end

  def teardown
    @account = nil
  end
end

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