Refactor Currency

Gemfile

@@ -16,6 +16,7 @@ gem 'yajl-ruby'
 
 group :development do
   gem 'minitest'
+  gem 'minitest-around'
   gem 'rack-test'
   gem 'shotgun'
 end

Gemfile.lock

@@ -18,6 +18,8 @@ GEM
     method_source (0.8.2)
     mini_portile (0.6.2)
     minitest (5.6.1)
+    minitest-around (0.3.2)
+      minitest (~> 5.0)
     multi_json (1.11.0)
     newrelic_rpm (3.12.0.288)
     nokogiri (1.6.6.2)
@@ -70,11 +72,11 @@ PLATFORMS
 DEPENDENCIES
   fixer
   minitest
+  minitest-around
   newrelic_rpm
   pry
   rack-test
   rake
-  rollbar
   sequel_pg
   shotgun
   sinatra-cross_origin
@@ -82,3 +84,6 @@ DEPENDENCIES
   unicorn
   virtus
   yajl-ruby
+
+BUNDLED WITH
+   1.10.6

lib/currency.rb

@@ -1,7 +1,21 @@
-# Wraps persisted currency data
 class Currency < Sequel::Model
-  def self.last_date
-    order(:date).last.date
+  dataset_module do
+    def recent
+      order(Sequel.desc(:date))
+    end
+
+    def before(value)
+      where { date <= value }
+    end
+
+    def current_date
+      currency = recent.first
+      currency.date if currency
+    end
+
+    def current_date_before(value)
+      before(value).current_date
+    end
   end
 
   def to_hash

lib/snapshot.rb

@@ -6,16 +6,14 @@ class Snapshot
   include Virtus.model
 
   attribute :base, String, default: 'EUR'
-  attribute :date, Date
+  attribute :date, Date, default: Currency.current_date
 
   def quote
     self.date =
       if date
-        last_date = Currency.where("date <= '#{date}'").order(:date).last
+        last_date = Currency.current_date_before(date)
         fail ArgumentError, 'Date too old' unless last_date
-        last_date.date
-      else
-        Currency.last_date
+        last_date
       end
 
     attributes.merge(rates: rebase(rates))

spec/currency_spec.rb

@@ -0,0 +1,33 @@
+require_relative 'helper'
+require 'currency'
+
+describe Currency do
+  around do |test|
+    Currency.db.transaction do
+      test.call
+      raise Sequel::Rollback
+    end
+  end
+
+  before do
+    Currency.dataset.delete
+    @first = Currency.create(date: '2014-01-01')
+    @last = Currency.create(date: '2015-01-01')
+  end
+
+  it 'returns current date' do
+    Currency.current_date.must_equal @last.date
+  end
+
+  it 'returns current date before given date' do
+    Currency.current_date_before(@last.date - 1).must_equal @first.date
+  end
+
+  it 'returns nil if there is no current date before given date' do
+    Currency.current_date_before(@first.date - 1).must_be_nil
+  end
+
+  it 'casts to hash' do
+    @first.to_hash.must_be_kind_of Hash
+  end
+end

spec/helper.rb

@@ -2,3 +2,4 @@ ENV['RACK_ENV'] = 'test'
 require './config/environment'
 require 'minitest/autorun'
 require 'minitest/pride'
+require 'minitest/around/spec'