Implement time series

... along with some minor miscellaneous refactoring

This finally completes fixerAPI/fixer#22

.rubocop.yml

@@ -3,6 +3,6 @@ AllCops:
 Documentation:
   Enabled: false
 Metrics/BlockLength:
-  Enabled: false
-Metrics/LineLength:
-  Enabled: false
+  ExcludedMethods: ['describe', 'helpers']
+Metrics/MethodLength:
+  Max: 11

README.md

@@ -8,10 +8,10 @@ Rates are updated around 4PM CET every working day.
 
 ## Usage
 
-Get the latest foreign exchange rates.
+Get the current foreign exchange rates.
 
 ```http
-GET /latest
+GET /current
 ```
 
 Get historical rates for any day since 1999.
@@ -23,25 +23,25 @@ GET /2000-01-03
 Rates quote against the Euro by default. Quote against a different currency.
 
 ```http
-GET /latest?from=USD
+GET /current?from=USD
 ```
 
 Request specific exchange rates.
 
 ```http
-GET /latest?to=GBP
+GET /current?to=GBP
 ```
 
-Change the amount requested.
+Change the converted amount.
 
 ```http
-GET /latest?amount=100
+GET /current?amount=100
 ```
 
 Finally, use all the above together.
 
 ```http
-GET /latest?from=EUR&to=GBP&amount=100
+GET /current?from=EUR&to=GBP&amount=100
 ```
 
 The primary use case is client side. For instance, with [money.js](https://openexchangerates.github.io/money.js/) in the browser
@@ -52,7 +52,7 @@ let demo = () => {
   alert("£1 = $" + rate.toFixed(4))
 }
 
-fetch('https://yourdomain.com/latest')
+fetch('https://yourdomain.com/current')
   .then((resp) => resp.json())
   .then((data) => fx.rates = data.rates)
   .then(demo)

config/initializers/sequel.rb

@@ -4,4 +4,5 @@ require 'pg'
 require 'sequel'
 
 Sequel.single_threaded = true
-Sequel.connect(ENV['DATABASE_URL'] || "postgres://localhost/frankfurter_#{App.env}")
+Sequel.connect(ENV['DATABASE_URL'] ||
+               "postgres://localhost/frankfurter_#{App.env}")

lib/currency.rb

@@ -7,5 +7,24 @@ class Currency < Sequel::Model
                                .order(Sequel.desc(:date))
                                .limit(1))
     end
+
+    def between(date_interval)
+      query = where(date: date_interval).order(:date)
+      length = date_interval.last - date_interval.first
+      if length > 365
+        query.sampled('month')
+      elsif length > 90
+        query.sampled('week')
+      else
+        query
+      end
+    end
+
+    def sampled(precision)
+      sampled_date = Sequel.lit("date_trunc('#{precision}', date)")
+      select(:iso_code).select_append { avg(rate).as(rate) }
+                       .select_append(sampled_date.as(:date))
+                       .group(:iso_code, sampled_date)
+    end
   end
 end

lib/query.rb

@@ -6,19 +6,24 @@ class Query
   end
 
   def amount
-    @params[:amount].to_f if @params[:amount] # rubocop:disable Style/SafeNavigation
+    return unless @params[:amount]
+    @params[:amount].to_f
   end
 
   def base
-    @params.values_at(:base, :from).compact.first&.upcase
+    @params.values_at(:from, :base).compact.first&.upcase
   end
 
   def symbols
-    @params.values_at(:symbols, :to).compact.first&.split(',')
+    @params.values_at(:to, :symbols).compact.first&.split(',')
   end
 
   def date
-    @params[:date]
+    if @params[:date]
+      Date.parse(@params[:date])
+    else
+      (Date.parse(@params[:start_date])..Date.parse(@params[:end_date]))
+    end
   end
 
   def to_h

lib/quote.rb

@@ -1,61 +1,4 @@
 # frozen_string_literal: true
 
-require 'currency'
-
-class Quote
-  DEFAULT_BASE = 'EUR'
-
-  def initialize(amount: 1.0,
-                 base: DEFAULT_BASE,
-                 date: Date.today.to_s,
-                 symbols: nil)
-    @amount = amount
-    @base = base
-    @date = date
-    @symbols = symbols
-  end
-
-  def to_h
-    { base: @base, date: date, rates: calculate_rates }
-  end
-
-  def date
-    currencies.first[:date].to_s
-  end
-
-  private
-
-  def calculate_rates # rubocop:disable Metrics/AbcSize
-    rates = currencies.each_with_object({}) do |currency, hsh|
-      hsh[currency[:iso_code]] = currency[:rate]
-    end
-
-    return rates if @base == DEFAULT_BASE && @amount == 1.0
-
-    if @symbols.nil? || @symbols.include?(DEFAULT_BASE) || @base == DEFAULT_BASE
-      rates.update(DEFAULT_BASE => 1.0)
-    end
-    divisor = rates.delete(@base)
-
-    rates.sort.map! { |ic, rate| [ic, round(@amount * rate / divisor)] }.to_h
-  end
-
-  def currencies
-    @currencies ||= begin
-      scope = Currency.latest(@date)
-      scope = scope.where(iso_code: @symbols + [@base]) if @symbols
-
-      scope.order(:iso_code).naked
-    end
-  end
-
-  # To paraphrase Wikipedia, most currency pairs are quoted to four decimal
-  # places. An exception to this is exchange rates with a value of less than
-  # 1.000, which are quoted to five or six decimal places. Exchange rates
-  # greater than around 20 are usually quoted to three decimal places and
-  # exchange rates greater than 80 are quoted to two decimal places.
-  # Currencies over 5000 are usually quoted with no decimal places.
-  def round(rate)
-    Float(format('%.5g', rate))
-  end
-end
+require 'quote/end_of_day'
+require 'quote/interval'

lib/quote/base.rb

@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+require 'roundable'
+
+module Quote
+  class Base
+    include Roundable
+
+    DEFAULT_BASE = 'EUR'
+
+    attr_reader :amount, :base, :date, :symbols, :result
+
+    def initialize(date:, amount: 1.0, base: 'EUR', symbols: nil)
+      @date = date
+      @amount = amount
+      @base = base
+      @symbols = symbols
+      @result = {}
+    end
+
+    def perform
+      return false if result.frozen?
+
+      prepare_rates
+      rebase_rates if must_rebase?
+      result.freeze
+
+      true
+    end
+
+    def must_rebase?
+      base != 'EUR'
+    end
+
+    def formatted
+      raise NotImplementedError
+    end
+
+    def not_found?
+      result.empty?
+    end
+
+    def cache_key
+      raise NotImplementedError
+    end
+
+    private
+
+    def data
+      @data ||= fetch_data
+    end
+
+    def fetch_data
+      raise NotImplementedError
+    end
+
+    def prepare_rates
+      data.each_with_object(result) do |currency, result|
+        date = currency[:date].to_date.to_s
+        result[date] ||= {}
+        result[date][currency[:iso_code]] = round(amount * currency[:rate])
+      end
+    end
+
+    def rebase_rates
+      result.each do |date, rates|
+        add_euro(rates)
+
+        divisor = rates.delete(base)
+        result[date] = rates.sort
+                            .map! do |iso_code, rate|
+                              [iso_code, round(amount * rate / divisor)]
+                            end
+                            .to_h
+      end
+    end
+
+    def add_euro(rates)
+      rates['EUR'] = amount if symbols.nil? || symbols.include?('EUR')
+    end
+  end
+end

lib/quote/end_of_day.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'currency'
+require 'quote/base'
+
+module Quote
+  class EndOfDay < Base
+    def formatted
+      { base: base, date: result.keys.first, rates: result.values.first }
+    end
+
+    def cache_key
+      return if not_found?
+      Digest::MD5.hexdigest(result.keys.first)
+    end
+
+    private
+
+    def fetch_data
+      scope = Currency.latest(date)
+      scope = scope.where(iso_code: symbols + [base]) if symbols
+
+      scope.naked
+    end
+  end
+end

lib/quote/interval.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require 'currency'
+require 'quote/base'
+
+module Quote
+  class Interval < Base
+    def formatted
+      { base: base,
+        start_date: result.keys.first,
+        end_date: result.keys.last,
+        rates: result }
+    end
+
+    def cache_key
+      return if not_found?
+      Digest::MD5.hexdigest(result.keys.last)
+    end
+
+    private
+
+    def fetch_data
+      scope = Currency.between(date)
+      scope = scope.where(iso_code: symbols + [base]) if symbols
+
+      scope.naked
+    end
+  end
+end

lib/roundable.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+module Roundable
+  # To paraphrase Wikipedia, most currency pairs are quoted to four decimal
+  # places. An exception to this is exchange rates with a value of less than
+  # 1.000, which are quoted to five or six decimal places. Exchange rates
+  # greater than around 20 are usually quoted to three decimal places and
+  # exchange rates greater than 80 are quoted to two decimal places.
+  # Currencies over 5000 are usually quoted with no decimal places.
+  def round(value)
+    if value > 5000
+      value.round
+    elsif value > 80
+      Float(format('%.2f', value))
+    elsif value > 20
+      Float(format('%.3f', value))
+    elsif value > 1
+      Float(format('%.4f', value))
+    else
+      Float(format('%.5f', value))
+    end
+  end
+end

lib/web/public/stylesheets/application.css

@@ -2,25 +2,44 @@ body {
   font-family: 'Open Sans', sans-serif;
 }
 
-.navbar .navbar-nav .nav-link {
+strong {
+  background-color: #f8f9fa;
+}
+
+.navbar {
+  background-color: #337cf6;
   font-size: .875rem;
+  padding-bottom: 0;
+  padding-top: 0;
+}
+
+.navbar .nav-link {
+  color: #fff;
+}
+
+.navbar .nav-link:hover {
+  color: #f8f9fa;
 }
 
 .container {
-  max-width: 720px;
+  max-width: 600px;
 }
 
 .section {
   padding-top: 1em;
 }
 
+.hero {
+  margin: 2em 0;
+}
+
 .hero .container {
   text-align: center;
 }
 
 .hero .logo {
   padding-bottom: 1em;
-  width: 120px;
+  width: 100px;
 }
 
 .footer .container {
@@ -30,12 +49,10 @@ body {
 
 .hljs {
   background-color: #f8f9fa;
-  border: 2px solid #f8f9fa;
   padding: 1em;
 }
 
 .hljs:hover {
-  border-bottom-color: #dee2e6;
   cursor: pointer;
 }
 
@@ -44,41 +61,49 @@ body {
   font-style: normal;
 }
 
-#carbonads {
+@media screen and (max-width: 767px) {
+  .hero .logo {
+    width: 75px;
+  }
+
+  #carbonads {
     display: none;
+  }
 }
 
-/*
-@media screen and (max-width: 767px) {
-  #carbonads {
-    display: none;
-  }
-}
 @media screen and (min-width: 768px) {
   #carbonads {
-    background-color: #f0f0f0;
+    background-color: #f8f9fa;
     position: absolute;
     right: 24px;
-    top: 36px;
+    top: 24px;
     width: 150px;
   }
+
+  .carbon-text {
+    color: #495057;
+  }
+
   .carbon-img,
   .carbon-poweredby,
   .carbon-text {
     display: block;
     margin: 10px;
   }
+
   .carbon-text,
   .carbon-poweredby {
     line-height: 1.3;
     text-decoration: none;
   }
+
   .carbon-text {
     font-size: 13px;
   }
+
   .carbon-poweredby {
+    color: #6c757d;
     font-size: 11px;
-    color: #999;
   }
 }
-*/
+

lib/web/server.rb

@@ -15,6 +15,10 @@ use Rack::Cors do
 end
 
 configure :development do
+  require 'rack-livereload'
+
+  use Rack::LiveReload
+
   set :show_exceptions, :after_handler
 end
 
@@ -27,13 +31,30 @@ configure :test do
 end
 
 helpers do
-  def quote
-    @quote ||= begin
-      query = Query.new(params)
-      Quote.new(query.to_h)
+  def end_of_day_quote
+    @end_of_day_quote ||= begin
+      quote = Quote::EndOfDay.new(query)
+      quote.perform
+      halt 404 if quote.not_found?
+
+      quote
     end
   end
 
+  def interval_quote
+    @interval_quote ||= begin
+      quote = Quote::Interval.new(query)
+      quote.perform
+      halt 404 if quote.not_found?
+
+      quote
+    end
+  end
+
+  def query
+    Query.new(params).to_h
+  end
+
   def json(data)
     json = Oj.dump(data, mode: :compat)
     callback = params.delete('callback')
@@ -52,28 +73,25 @@ options '*' do
   200
 end
 
-get '*' do
-  cache_control :public
-  pass
-end
-
 get '/' do
   erb :index
 end
 
 get '/(?:latest|current)', mustermann_opts: { type: :regexp } do
-  last_modified quote.date
-  json quote.to_h
+  params[:date] = Date.today.to_s
+  etag end_of_day_quote.cache_key
+  json end_of_day_quote.formatted
 end
 
 get '/(?<date>\d{4}-\d{2}-\d{2})', mustermann_opts: { type: :regexp } do
-  last_modified quote.date
-  json quote.to_h
+  etag end_of_day_quote.cache_key
+  json end_of_day_quote.formatted
 end
 
-get '/(?<start_date>\d{4}-\d{2}-\d{2})\.\.(?<end_date>\d{4}-\d{2}-\d{2})', mustermann_opts: { type: :regexp } do
-  last_modified quote.end_date
-  json quote.to_h
+get '/(?<start_date>\d{4}-\d{2}-\d{2})\.\.(?<end_date>\d{4}-\d{2}-\d{2})',
+    mustermann_opts: { type: :regexp } do
+  etag interval_quote.cache_key
+  json interval_quote.formatted
 end
 
 not_found do

lib/web/views/index.erb

@@ -7,43 +7,43 @@
     <title>Frankfurter</title>
     <link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/github.min.css">
     <link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.1/css/bootstrap.min.css">
-    <link rel="stylesheet" href="//fonts.googleapis.com/css?family=Open+Sans:300,400">
+    <link rel="stylesheet" href="//fonts.googleapis.com/css?family=Open+Sans:300,400,600">
     <link rel="stylesheet" href="/stylesheets/application.css">
-    <link rel="shortcut icon" href="/images/frankfurter-icon.png">
+    <link rel="shortcut icon" href="/images/favicon.ico">
   </head>
   <body>
     <nav class="navbar navbar-expand">
       <div class="container">
-        <ul class="navbar-nav mx-sm-auto">
+        <ul class="navbar-nav mx-auto">
+          <li class="nav-item">
+            <a class="nav-link" href="https://github.com/hakanensari/frankfurter" target="_blank">Source code</a>
+          </li>
           <li class="nav-item">
             <a class="nav-link" href="https://www.ecb.europa.eu/stats/exchange/eurofxref/html/index.en.html" target="_blank">Data sets</a>
           </li>
           <li class="nav-item">
             <a class="nav-link" href="https://status.frankfurter.app/" target="_blank">Status</a>
           </li>
-          <li class="nav-item">
-            <a class="nav-link" href="https://github.com/hakanensari/frankfurter" target="_blank">Source</a>
-          </li>
         </ul>
       </div>
     </nav>
     <section class="hero section">
       <div class="container">
+        <image class="logo" src="/images/frankfurter.png" alt="">
         <h1 class="display-4">Frankfurter</h1>
         <p class="lead">
           Foreign exchange rates and currency conversion API
         </p>
-        <img alt="" class="logo" src="/images/frankfurter.png">
       </div>
     </section>
 
     <section class="introduction section">
       <div class="container">
         <p>
-          Frankfurter is a lightweight API for querying current and historical forex rates published by the European Central Bank.
+          Frankfurter is an open-source API for current and historical forex rates published by the European Central Bank.
         </p>
         <p>
-          Rates update around 4PM CET on every working day. Historical data goes back to early 1999.
+          The API updates rates around 4PM CET every working day. Historical data goes back to early 1999.
         </p>
       </div>
     </section>
@@ -58,7 +58,11 @@
         <p>
           Get historical rates for any day since 1999.
         </p>
-        <pre><code class="http hljs small">GET /1999-12-31 <i>HTTP/1.1</i></code></pre>
+        <pre><code class="http hljs small">GET /2000-01-01 <i>HTTP/1.1</i></code></pre>
+        <p>
+          Get historical exchange rates for a given time period.
+        </p>
+        <pre><code class="http hljs small">GET /2000-01-01..2000-12-31 <i>HTTP/1.1</i></code></pre>
         <p>
           Rates are quoted against the Euro by default. Quote against a different
           currency by setting the <strong>from</strong> parameter in your request.
@@ -69,9 +73,9 @@
         </p>
         <pre><code class="http hljs small">GET /current?to=USD,GBP <i>HTTP/1.1</i></code></pre>
         <p>
-          Convert a specific value.
+          Convert a specific value using <strong>amount</strong>.
         </p>
-        <pre><code class="http hljs small">GET /current?amount=1000&from=GBP&to=EUR <i>HTTP/1.1</i></code></pre>
+        <pre><code class="http hljs small">GET /current?amount=1000 <i>HTTP/1.1</i></code></pre>
       </div>
     </section>
     <section class="best-practices section">
@@ -110,9 +114,9 @@ fetch('/current?from=GBP&to=USD')
         <iframe src="https://ghbtns.com/github-btn.html?user=hakanensari&repo=frankfurter&type=star&count=true" frameborder="0" scrolling="0" width="120px" height="20px"></iframe>
       </div>
     </section>
-    <script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/highlight.min.js"></script>
-    <script src="/javascripts/application.js"></script>
-    <script async type="text/javascript" src="//cdn.carbonads.com/carbon.js?zoneid=1673&serve=C6AILKT&placement=fixerio" id="_carbonads_js"></script>
+    <script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/highlight.min.js"></script>
+    <script type="text/javascript" src="/javascripts/application.js"></script>
+    <script async type="text/javascript" src="//cdn.carbonads.com/carbon.js?serve=CK7D45QM&placement=frankfurterapp" id="_carbonads_js"></script>
   </body>
 </html>
 

spec/currency_spec.rb

@@ -4,37 +4,52 @@ 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
-    @earlier = [
-      Currency.create(iso_code: 'EUR', rate: 1, date: '2014-01-01'),
-      Currency.create(iso_code: 'USD', rate: 2, date: '2014-01-01')
-    ]
-    @later = [
-      Currency.create(iso_code: 'EUR', rate: 1, date: '2015-01-01'),
-      Currency.create(iso_code: 'USD', rate: 2, date: '2015-01-01')
-    ]
-  end
-
-  it 'returns latest rates' do
-    data = Currency.latest.to_a
-    data.sample.date.must_equal @later.sample.date
+  describe '.current' do
+    it 'returns current rates' do
+      date = Currency.order(Sequel.desc(:date)).first.date
+      rates = Currency.latest
+      rates.first.date.must_equal date
     end
 
     it 'returns latest rates before given date' do
-    data = Currency.latest(@later.sample.date - 1).to_a
-    data.sample.date.must_equal @earlier.sample.date
+      date = Date.parse('2010-01-01')
+      rates = Currency.latest(date)
+      rates.first.date.must_be :<=, date
     end
 
     it 'returns nothing if there are no rates before given date' do
-    data = Currency.latest(@earlier.sample.date - 1).to_a
-    data.must_be_empty
+      rates = Currency.latest(Date.parse('1998-01-01'))
+      rates.must_be_empty
+    end
+  end
+
+  describe '.between' do
+    it 'returns rates between given dates' do
+      start_date = Date.parse('2010-01-01')
+      end_date = Date.parse('2010-01-31')
+      dates = Currency.between((start_date..end_date)).map(:date).uniq.sort
+      dates.first.must_be :>=, start_date
+      dates.last.must_be :<=, end_date
+    end
+
+    it 'returns nothing if there are no rates between given dates' do
+      date_interval = (Date.parse('1998-01-01')..Date.parse('1998-01-31'))
+      Currency.between(date_interval).must_be_empty
+    end
+
+    it 'returns all rates up to 90 days' do
+      date_interval = (Date.parse('2010-01-01')..Date.parse('2010-03-01'))
+      Currency.between(date_interval).map(:date).uniq.count.must_be :>, 30
+    end
+
+    it 'samples weeks over 90 days and below 366 days' do
+      date_interval = (Date.parse('2010-01-01')..Date.parse('2010-12-31'))
+      Currency.between(date_interval).map(:date).uniq.count.must_be :<=, 52
+    end
+
+    it 'samples months over 365 days' do
+      date_interval = (Date.parse('2001-01-01')..Date.parse('2010-12-31'))
+      Currency.between(date_interval).map(:date).uniq.count.must_be :<=, 120
+    end
   end
 end

spec/edge_cases_spec.rb

@@ -25,7 +25,7 @@ describe 'the API' do
 
   it 'will not process a date before 2000' do
     get '/1999-01-01'
-    last_response.must_be :unprocessable?
+    last_response.must_be :not_found?
   end
 
   it 'will not process an invalid base' do

spec/helper.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+ENV['APP_ENV'] ||= 'test'
+
 require_relative '../config/environment'
 
 require 'minitest/autorun'

spec/query_spec.rb

@@ -9,7 +9,7 @@ describe Query do
     query.amount.must_equal 100.0
   end
 
-  it 'defaults amount to nothin' do
+  it 'defaults amount to nothing' do
     query = Query.new
     query.amount.must_be_nil
   end
@@ -24,7 +24,7 @@ describe Query do
     query.base.must_be_nil
   end
 
-  it 'aliases base as from' do
+  it 'aliases base with from' do
     query = Query.new(from: 'USD')
     query.base.must_equal 'USD'
   end
@@ -34,7 +34,7 @@ describe Query do
     query.symbols.must_equal %w[USD GBP]
   end
 
-  it 'aliases symbols to to' do
+  it 'aliases symbols with to' do
     query = Query.new(to: 'USD')
     query.symbols.must_equal ['USD']
   end
@@ -45,12 +45,15 @@ describe Query do
   end
 
   it 'returns given date' do
-    query = Query.new(date: '2014-01-01')
-    query.date.must_equal '2014-01-01'
+    date = '2014-01-01'
+    query = Query.new(date: date)
+    query.date.must_equal Date.parse(date)
   end
 
-  it 'defaults date to nothing' do
-    query = Query.new
-    query.date.must_be_nil
+  it 'returns given date interval' do
+    start_date = '2014-01-01'
+    end_date = '2014-12-31'
+    query = Query.new(start_date: start_date, end_date: end_date)
+    query.date.must_equal((Date.parse(start_date)..Date.parse(end_date)))
   end
 end

spec/quote/base_spec.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require_relative '../helper'
+require 'quote/base'
+
+module Quote
+  describe Base do
+    let(:klass) do
+      Class.new(Base)
+    end
+
+    let(:quote) do
+      klass.new(date: Date.today)
+    end
+
+    it 'requires data' do
+      -> { quote.perform }.must_raise NotImplementedError
+    end
+
+    it 'does not know how to format result' do
+      -> { quote.formatted }.must_raise NotImplementedError
+    end
+
+    it 'does not know how to generate a cache key' do
+      -> { quote.cache_key }.must_raise NotImplementedError
+    end
+
+    it 'defaults base to Euro' do
+      quote.base.must_equal 'EUR'
+    end
+
+    it 'defaults amount to 1' do
+      quote.amount.must_equal 1
+    end
+
+    describe 'when given data' do
+      let(:klass) do
+        Class.new(Base) do
+          def fetch_data
+            []
+          end
+        end
+      end
+
+      it 'performs' do
+        assert quote.perform
+      end
+
+      it 'performs only once' do
+        quote.perform
+        refute quote.perform
+      end
+    end
+  end
+end

spec/quote/end_of_day_spec.rb

@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+require_relative '../helper'
+require 'quote/end_of_day'
+
+module Quote
+  describe EndOfDay do
+    let(:date) do
+      Date.parse('2010-10-10')
+    end
+
+    let(:quote) do
+      EndOfDay.new(date: date)
+    end
+
+    before do
+      quote.perform
+    end
+
+    it 'returns rates' do
+      quote.formatted[:rates].wont_be :empty?
+    end
+
+    it 'quotes given date' do
+      Date.parse(quote.formatted[:date]).must_be :<=, date
+    end
+
+    it 'quotes against the Euro' do
+      quote.formatted[:rates].keys.wont_include 'EUR'
+    end
+
+    it 'sorts rates' do
+      rates = quote.formatted[:rates]
+      rates.keys.must_equal rates.keys.sort
+    end
+
+    it 'has a cache key' do
+      quote.cache_key.wont_be :empty?
+    end
+
+    describe 'given a new base' do
+      let(:quote) do
+        EndOfDay.new(date: date, base: 'USD')
+      end
+
+      it 'quotes against that base' do
+        quote.formatted[:rates].keys.wont_include 'USD'
+      end
+
+      it 'sorts rates' do
+        rates = quote.formatted[:rates]
+        rates.keys.must_equal rates.keys.sort
+      end
+    end
+
+    describe 'given symbols' do
+      let(:quote) do
+        EndOfDay.new(date: date, symbols: %w[USD GBP JPY])
+      end
+
+      it 'quotes only for those symbols' do
+        rates = quote.formatted[:rates]
+        rates.keys.must_include 'USD'
+        rates.keys.wont_include 'CAD'
+      end
+
+      it 'sorts rates' do
+        rates = quote.formatted[:rates]
+        rates.keys.must_equal rates.keys.sort
+      end
+    end
+
+    describe 'when given an amount' do
+      let(:quote) do
+        EndOfDay.new(date: date, amount: 100)
+      end
+
+      it 'calculates quotes for that amount' do
+        quote.formatted[:rates]['USD'].must_be :>, 10
+      end
+    end
+  end
+end

spec/quote/interval_spec.rb

@@ -0,0 +1,94 @@
+# frozen_string_literal: true
+
+require_relative '../helper'
+require 'quote/interval'
+
+module Quote
+  describe Interval do
+    let(:date_interval) do
+      (Date.parse('2010-01-01')..Date.parse('2010-12-31'))
+    end
+
+    let(:quote) do
+      Interval.new(date: date_interval)
+    end
+
+    before do
+      quote.perform
+    end
+
+    it 'returns rates' do
+      quote.formatted[:rates].wont_be :empty?
+    end
+
+    it 'quotes given date interval' do
+      Date.parse(quote.formatted[:start_date]).must_be :>=, date_interval.first
+      Date.parse(quote.formatted[:end_date]).must_be :<=, date_interval.last
+    end
+
+    it 'quotes against the Euro' do
+      quote.formatted[:rates].each_value do |rates|
+        rates.keys.wont_include 'EUR'
+      end
+    end
+
+    it 'sorts rates' do
+      quote.formatted[:rates].each_value do |rates|
+        rates.keys.must_equal rates.keys.sort
+      end
+    end
+
+    it 'has a cache key' do
+      quote.cache_key.wont_be :empty?
+    end
+
+    describe 'given a new base' do
+      let(:quote) do
+        Interval.new(date: date_interval, base: 'USD')
+      end
+
+      it 'quotes against that base' do
+        quote.formatted[:rates].each_value do |rates|
+          rates.keys.wont_include 'USD'
+        end
+      end
+
+      it 'sorts rates' do
+        quote.formatted[:rates].each_value do |rates|
+          rates.keys.must_equal rates.keys.sort
+        end
+      end
+    end
+
+    describe 'given symbols' do
+      let(:quote) do
+        Interval.new(date: date_interval, symbols: %w[USD GBP JPY])
+      end
+
+      it 'quotes only for those symbols' do
+        quote.formatted[:rates].each_value do |rates|
+          rates.keys.must_include 'USD'
+          rates.keys.wont_include 'CAD'
+        end
+      end
+
+      it 'sorts rates' do
+        quote.formatted[:rates].each_value do |rates|
+          rates.keys.must_equal rates.keys.sort
+        end
+      end
+    end
+
+    describe 'when given an amount' do
+      let(:quote) do
+        Interval.new(date: date_interval, amount: 100)
+      end
+
+      it 'calculates quotes for that amount' do
+        quote.formatted[:rates].each_value do |rates|
+          rates['USD'].must_be :>, 10
+        end
+      end
+    end
+  end
+end

spec/quote_spec.rb

@@ -1,53 +0,0 @@
-# frozen_string_literal: true
-
-require_relative 'helper'
-require 'quote'
-
-describe Quote do
-  describe 'by default' do
-    it 'quotes against the Euro' do
-      quote = Quote.new
-      rates = quote.to_h[:rates]
-      rates.keys.wont_include 'EUR'
-    end
-  end
-
-  describe 'when given a base' do
-    it 'quotes against that base' do
-      quote = Quote.new(base: 'USD')
-      rates = quote.to_h[:rates]
-      rates.keys.wont_include 'USD'
-    end
-
-    it 'sorts rates' do
-      quote = Quote.new(base: 'USD')
-      rates = quote.to_h[:rates]
-      rates.keys.must_equal rates.keys.sort
-    end
-  end
-
-  describe 'when given symbols' do
-    it 'quotes rates only for given symbols' do
-      quote = Quote.new(symbols: ['USD'])
-      rates = quote.to_h[:rates]
-      rates.keys.must_include 'USD'
-      rates.keys.wont_include 'GBP'
-    end
-  end
-
-  describe 'when given an amount' do
-    it 'quotes for that amount' do
-      quote = Quote.new(amount: 100)
-      rates = quote.to_h[:rates]
-      rates['USD'].must_be :>, 10
-    end
-  end
-
-  describe 'when given an amount and symbols' do
-    it 'quotes for that amount' do
-      quote = Quote.new(amount: 100, symbols: ['USD'])
-      rates = quote.to_h[:rates]
-      rates['USD'].must_be :>, 10
-    end
-  end
-end

spec/roundable_spec.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require_relative 'helper'
+require 'roundable'
+
+describe Roundable do
+  include Roundable
+
+  it 'rounds values over 5,000 to zero decimal places' do
+    round(5000.123456).must_equal 5000.0
+  end
+
+  it 'rounds values over 80 and below 5,000 to two decimal places' do
+    round(80.123456).must_equal 80.12
+    round(4999.123456).must_equal 4999.12
+  end
+
+  it 'rounds values over 20 and below 80 to three decimal places' do
+    round(79.123456).must_equal 79.123
+    round(20.123456).must_equal 20.123
+  end
+
+  it 'rounds values over 1 and below 20 to four decimal places' do
+    round(19.123456).must_equal 19.1235
+    round(1.123456).must_equal 1.1235
+  end
+
+  it 'rounds values below 1 to five decimal places' do
+    round(0.123456).must_equal 0.12346
+  end
+end

spec/web/server_spec.rb

@@ -49,17 +49,10 @@ describe 'the server' do
     json['rates'].wont_be :empty?
   end
 
-  it 'returns a cache control header' do
-    %w[/ /current /2012-11-20].each do |path|
-      get path
-      headers['Cache-Control'].wont_be_nil
-    end
-  end
-
-  it 'returns a last modified header' do
+  it 'returns an ETag' do
     %w[/current /2012-11-20].each do |path|
       get path
-      headers['Last-Modified'].wont_be_nil
+      headers['ETag'].wont_be_nil
     end
   end
 
@@ -88,8 +81,8 @@ describe 'the server' do
 
   it 'returns rates for a given period' do
     get '/2010-01-01..2010-12-31'
-    json['start_date'].must_equal '2010-01-01'
-    json['end_date'].must_equal '2010-12-31'
-    json['rates'].wont_be empty
+    json['start_date'].wont_be :empty?
+    json['end_date'].wont_be :empty?
+    json['rates'].wont_be :empty?
   end
 end