You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: category_test.rb
    path of file: ./repos/workarea/core/test/models/workarea/tax
    
    the code of the file until where you have to start completion: require 'test_helper'

module Workarea
  module Tax
    class CategoryTest < TestCase
      def test_find_by_code
        category = create_tax_category(code: '001')
        assert_equal(category, Workarea::Tax::Category.find_by_code('001'))
      end

      def test_tiered?
        category = create_tax_category(rates: [])
        refute(category.tiered?)

        category.rates.create!(country: 'US')
        refute(category.tiered?)
        category.rates.delete_all

        category.rates.create!(country: 'US', tier_min: 0, tier_max: 5)
        category.rates.create!(country: 'US', tier_min
    
      def test_find_rate_location_specific
        category = create_tax_category(code: '002', rates: [])

        philly = category.rates.create!(country: 'US', region: 'PA', postal_code: '19106')
        alberta = category.rates.create!(country: 'CA', region: 'AB')
        british_columbia = category.rates.create!(country: 'CA', region: 'BC')
        _uk = category.rates.create!(country: 'UK')

        assert_nil(category.find_rate(0.to_m, nil, nil, nil))
        assert_nil(category.find_rate(0.to_m, 'CA', nil, nil))
        assert_equal(alberta, category.find_rate(0.to_m, 'CA', 'AB', nil))
        assert_equal(british_columbia, category.find_rate(0.to_m, 'CA', 'BC', nil))
        assert_equal(philly, category.find_rate(0.to_m, 'US', 'PA', '19106'))
        assert_equal(alberta, category.find_rate(0.to_m, 'CA', 'AB', '19106'))
      end