Creating a Groovy DSL for Financial Product Fee Schedules

I'm currently working on a project that requires a variable fee schedule.
E.g.

Product Name	Category	Feature	Value	Date Range		Functional Setting Applicability
General ACH Generation
	ACH Generation Fees	ACH Transaction Fee	1.00	Account Open Date	Account Closed Date	0 to 10 transactions
		ACH Transaction Fee	.50	Account Open Date	Account Closed Date	10 or more transactions
	Credit Card Generation Fees	CC Transaction Fee	1.00	Account Open Date	Account Closed Date	0 to 10 transactions
		CC Transaction Fee	.50	Account Open Date	Account Closed Date	10 or more transactions

I need a way to specify the date range that would include things such as account open date and plus 3 months and transaction ranges. Groovy DSL seems like the perfect fit. See Guillame Laforge's example here.

I came up with the following:

package com.aps.utils

import com.aps.util.DateUtil
import org.codehaus.groovy.runtime.TimeCategory


class ProductCatalogDSLTests extends GroovyTestCase {


  def account

  void setUp() {
    account = new Account(from: DateUtil.sdf.parse("01-01-2010"))
  }

  void testAccountOpenedDate() {
    def rule = 'transactionDate > account.from'
    def binding = new Binding()
    binding.account = account
    def shell = new GroovyShell(binding)
    def date = DateUtil.sdf.parse('01-10-2010')
    binding.transactionDate = date
    assert shell.evaluate(rule)
    binding.transactionDate = DateUtil.sdf.parse('05-10-2009')
    assertFalse shell.evaluate(rule)

  }

  void testAccountOpenedDate_plus3() {
    def rule = 'transactionDate < account.from+6.months'
    def binding = new Binding()
    binding.account = account
    def shell = new GroovyShell(binding)
    def date = DateUtil.sdf.parse('01-10-2010')
    binding.transactionDate = date
    use(TimeCategory) {
      assert shell.evaluate(rule)
      binding.transactionDate = DateUtil.sdf.parse('05-10-2010')
      assert shell.evaluate(rule)
    }
  }

  void testTransactionMinimum() {
    def rule1 = 'account.transactions.size < 10'
    def rule2 = 'account.transactions.size >= 10'
    def date = DateUtil.sdf.parse('01-10-2010')
    0..5.each {
      account.transactions << new AccountTransaction(amount: 15.00, postDate: date)
    }
    def binding = new Binding()
    binding.account = account
    def shell = new GroovyShell(binding)
    binding.transactionDate = date
    use(TimeCategory) {
      assert shell.evaluate(rule1)
      assertFalse shell.evaluate(rule2)
    }
  }

  void testTransactionMinimumThisMonth() {
    def rule1 = 'account.transactions.collect{it.postDate.month == transactionDate.month}.size < 10'
    def rule2 = 'account.transactions.collect{it.postDate.month == transactionDate.month}.size >= 10'
    def date = DateUtil.sdf.parse('01-10-2010')
    use(TimeCategory) {
      assertEquals 0 , date.month
      assertEquals 10 , date.date
      assertEquals 2010 - 1900 , date.year
      0..5.each {
        account.transactions << new AccountTransaction(amount: 15.00, postDate: date)
      }
      def binding = new Binding()
      binding.account = account
      def shell = new GroovyShell(binding)
      binding.transactionDate = date
      assert shell.evaluate(rule1)
      assertFalse shell.evaluate(rule2)
    }
  }
}
class Account {
  Date from
  Date to
  def transactions = []
}
class AccountTransaction {
  BigDecimal amount
  Date postDate
}

It ended up working well for dynamic business rule selectors.