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Introduce SortableEvents for user-defined events sorting/reordering

Akinori MUSHA 9 years ago
parent
06554eaf31
commit
f86c9c5027
3 changed files with 419 additions and 0 deletions
Show Diff Stats
  1. 154 0
      app/concerns/sortable_events.rb
  2. 1 0
      app/models/agent.rb
  3. 264 0
      spec/concerns/sortable_events_spec.rb

+ 154 - 0
app/concerns/sortable_events.rb
View File 

@@ -0,0 +1,154 @@
1 
+module SortableEvents
2 
+  extend ActiveSupport::Concern
3 
+
4 
+  included do
5 
+    validate :validate_events_order
6 
+  end
7 
+
8 
+  def description_events_order(events = 'events created in each run')
9 
+    <<-MD.lstrip
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+        To specify the order of #{events}, set `events_order` to an array of sort keys, each of which looks like either `expression` or `[expression, type, descending]`, as described as follows:
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+
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+        * _expression_ is a Liquid template to generate a string to be used as sort key.
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+
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+        * _type_ (optional) is one of `string` (default), `number` and `time`, which specifies how to evaluate _expression_ for comparison.
15 
+
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+        * _descending_ (optional) is a boolean value to determine if comparison should be done in descending (reverse) order, which defaults to `false`.
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+
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+        Sort keys listed eariler take precedence over ones listed later.  For example, if you want to sort articles by the date and then by the author, specify `[["{{date}}", "time"], "{{author}}"]`.
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+
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+        Sorting is done stably, so even if all events have the same set of sort key values the original order is retained.  Also, a special Liquid variable `_index_` is provided, which contains the zero-based index number of each event, which means you can exactly reverse the order of events by specifying `[["{{_index_}}", "number", true]]`.
21 
+    MD
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+  end
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+
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+  module ClassMethods
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+    def can_order_created_events!
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+      raise if cannot_create_events?
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+      prepend AutomaticSorter
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+    end
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+
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+    def can_order_created_events?
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+      include? AutomaticSorter
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+    end
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+
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+    def cannot_order_created_events?
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+      !can_order_created_events?
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+    end
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+  end
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+
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+  def can_order_created_events?
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+    self.class.__send__(__callee__)
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+  end
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+
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+  def cannot_order_created_events?
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+    self.class.__send__(__callee__)
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+  end
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+
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+  def events_order
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+    options['events_order']
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+  end
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+
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+  module AutomaticSorter
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+    def check
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+      return super unless events_order
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+      sorting_events do
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+        super
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+      end
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+    end
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+
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+    def receive(incoming_events)
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+      return super unless events_order
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+      # incoming events should be processed sequentially
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+      incoming_events.each do |event|
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+        sorting_events do
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+          super([event])
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+        end
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+      end
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+    end
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+
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+    def create_event(attrs)
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+      if @sortable_events
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+        @sortable_events << events.build({ user: user }.merge(attrs))
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+      else
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+        super
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+      end
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+    end
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+
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+    private
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+
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+    def sorting_events(&block)
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+      @sortable_events = []
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+      yield
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+    ensure
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+      events, @sortable_events = @sortable_events, nil
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+      sort_events(events).each do |event|
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+        event.expires_at ||= new_event_expiration_date
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+        event.save!
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+      end
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+    end
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+  end
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+
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+  private
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+
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+  EXPRESSION_PARSER = {
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+    'string' => ->string { string },
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+    'number' => ->string { string.to_f },
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+    'time'   => ->string { Time.zone.parse(string) },
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+  }
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+  EXPRESSION_TYPES = EXPRESSION_PARSER.keys.freeze
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+
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+  def validate_events_order
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+    case order_by = events_order()
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+    when nil
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+    when Array
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+      # Each tuple may be either [expression, type, desc] or just
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+      # expression.
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+      order_by.each do |expression, type, desc|
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+        case expression
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+        when String
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+          # ok
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+        else
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+          errors.add(:base, "first element of each events_order tuple must be a Liquid template")
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+          break
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+        end
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+        case type
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+        when nil, *EXPRESSION_TYPES
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+          # ok
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+        else
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+          errors.add(:base, "second element of each events_order tuple must be #{EXPRESSION_TYPES.to_sentence(last_word_connector: ' or ')}")
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+          break
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+        end
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+        if !desc.nil? && boolify(desc).nil?
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+          errors.add(:base, "third element of each events_order tuple must be a boolean value")
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+          break
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+        end
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+      end
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+    else
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+      errors.add(:base, "events_order must be an array of arrays")
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+    end
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+  end
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+
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+  # Sort given events in order specified by the "events_order" option
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+  def sort_events(events)
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+    order_by = events_order().presence or return events
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+    orders = order_by.map { |_, _, desc = false| boolify(desc) }
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+
136 
+    Utils.sort_tuples!(
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+      events.map.with_index { |event, index|
138 
+        interpolate_with(event) {
139 
+          interpolation_context['_index_'] = index
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+          order_by.map { |expression, type, _|
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+            string = interpolate_string(expression)
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+            begin
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+              EXPRESSION_PARSER[type || 'string'.freeze][string]
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+            rescue
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+              error "Cannot parse #{string.inspect} as #{type}; treating it as string"
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+              string
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+            end
148 
+          }
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+        } << index << event  # index is to make sorting stable
150 
+      },
151 
+      orders
152 
+    ).collect!(&:last)
153 
+  end
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+end

+ 1 - 0
app/models/agent.rb
View File 

@@ -13,6 +13,7 @@ class Agent < ActiveRecord::Base
13 13 
   include HasGuid
14 14 
   include LiquidDroppable
15 15 
   include DryRunnable
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+  include SortableEvents
16 17
17 18 
   markdown_class_attributes :description, :event_description
18 19

+ 264 - 0
spec/concerns/sortable_events_spec.rb
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@@ -0,0 +1,264 @@
1 
+require 'spec_helper'
2 
+
3 
+describe SortableEvents do
4 
+  let(:agent_class) {
5 
+    Class.new(Agent) do
6 
+      include SortableEvents
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+
8 
+      default_schedule 'never'
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+
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+      def self.valid_type?(name)
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+        true
12 
+      end
13 
+    end
14 
+  }
15 
+
16 
+  def new_agent(events_order = nil)
17 
+    options = {}
18 
+    options['events_order'] = events_order if events_order
19 
+    agent_class.new(name: 'test', options: options) { |agent|
20 
+      agent.user = users(:bob)
21 
+    }
22 
+  end
23 
+
24 
+  describe 'validations' do
25 
+    let(:agent_class) {
26 
+      Class.new(Agent) do
27 
+        include SortableEvents
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+
29 
+        default_schedule 'never'
30 
+
31 
+        def self.valid_type?(name)
32 
+          true
33 
+        end
34 
+      end
35 
+    }
36 
+
37 
+    def new_agent(events_order = nil)
38 
+      options = {}
39 
+      options['events_order'] = events_order if events_order
40 
+      agent_class.new(name: 'test', options: options) { |agent|
41 
+        agent.user = users(:bob)
42 
+      }
43 
+    end
44 
+
45 
+    it 'should allow events_order to be unspecified, null or an empty array' do
46 
+      expect(new_agent()).to be_valid
47 
+      expect(new_agent(nil)).to be_valid
48 
+      expect(new_agent([])).to be_valid
49 
+    end
50 
+
51 
+    it 'should not allow events_order to be a non-array object' do
52 
+      agent = new_agent(0)
53 
+      expect(agent).not_to be_valid
54 
+      expect(agent.errors[:base]).to include(/events_order/)
55 
+
56 
+      agent = new_agent('')
57 
+      expect(agent).not_to be_valid
58 
+      expect(agent.errors[:base]).to include(/events_order/)
59 
+
60 
+      agent = new_agent({})
61 
+      expect(agent).not_to be_valid
62 
+      expect(agent.errors[:base]).to include(/events_order/)
63 
+    end
64 
+
65 
+    it 'should not allow events_order to be an array containing unexpected objects' do
66 
+      agent = new_agent(['{{key}}', 1])
67 
+      expect(agent).not_to be_valid
68 
+      expect(agent.errors[:base]).to include(/events_order/)
69 
+
70 
+      agent = new_agent(['{{key1}}', ['{{key2}}', 'unknown']])
71 
+      expect(agent).not_to be_valid
72 
+      expect(agent.errors[:base]).to include(/events_order/)
73 
+    end
74 
+
75 
+    it 'should allow events_order to be an array containing strings and valid tuples' do
76 
+      agent = new_agent(['{{key1}}', ['{{key2}}'], ['{{key3}}', 'number']])
77 
+      expect(agent).to be_valid
78 
+
79 
+      agent = new_agent(['{{key1}}', ['{{key2}}'], ['{{key3}}', 'number'], ['{{key4}}', 'time', true]])
80 
+      expect(agent).to be_valid
81 
+    end
82 
+  end
83 
+
84 
+  describe 'sort_events' do
85 
+    let(:payloads) {
86 
+      [
87 
+        { 'title' => 'TitleA', 'score' => 4,  'updated_on' => '7 Jul 2015' },
88 
+        { 'title' => 'TitleB', 'score' => 2,  'updated_on' => '25 Jun 2014' },
89 
+        { 'title' => 'TitleD', 'score' => 10, 'updated_on' => '10 Jan 2015' },
90 
+        { 'title' => 'TitleC', 'score' => 10, 'updated_on' => '9 Feb 2015' },
91 
+      ]
92 
+    }
93 
+
94 
+    let(:events) {
95 
+      payloads.map { |payload| Event.new(payload: payload) }
96 
+    }
97 
+
98 
+    it 'should sort events by a given key' do
99 
+      agent = new_agent(['{{title}}'])
100 
+      expect(agent.__send__(:sort_events, events).map { |e| e.payload['title'] }).to eq(%w[TitleA TitleB TitleC TitleD])
101 
+
102 
+      agent = new_agent([['{{title}}', 'string', true]])
103 
+      expect(agent.__send__(:sort_events, events).map { |e| e.payload['title'] }).to eq(%w[TitleD TitleC TitleB TitleA])
104 
+    end
105 
+
106 
+    it 'should sort events by multiple keys' do
107 
+      agent = new_agent([['{{score}}', 'number'], '{{title}}'])
108 
+      expect(agent.__send__(:sort_events, events).map { |e| e.payload['title'] }).to eq(%w[TitleB TitleA TitleC TitleD])
109 
+
110 
+      agent = new_agent([['{{score}}', 'number'], ['{{title}}', 'string', true]])
111 
+      expect(agent.__send__(:sort_events, events).map { |e| e.payload['title'] }).to eq(%w[TitleB TitleA TitleD TitleC])
112 
+    end
113 
+
114 
+    it 'should sort events by time' do
115 
+      agent = new_agent([['{{updated_on}}', 'time']])
116 
+      expect(agent.__send__(:sort_events, events).map { |e| e.payload['title'] }).to eq(%w[TitleB TitleD TitleC TitleA])
117 
+    end
118 
+
119 
+    it 'should sort events stably' do
120 
+      agent = new_agent(['<constant>'])
121 
+      expect(agent.__send__(:sort_events, events).map { |e| e.payload['title'] }).to eq(%w[TitleA TitleB TitleD TitleC])
122 
+
123 
+      agent = new_agent([['<constant>', 'string', true]])
124 
+      expect(agent.__send__(:sort_events, events).map { |e| e.payload['title'] }).to eq(%w[TitleA TitleB TitleD TitleC])
125 
+    end
126 
+
127 
+    it 'should support _index_' do
128 
+      agent = new_agent([['{{_index_}}', 'number', true]])
129 
+      expect(agent.__send__(:sort_events, events).map { |e| e.payload['title'] }).to eq(%w[TitleC TitleD TitleB TitleA])
130 
+    end
131 
+  end
132 
+
133 
+  describe 'automatic event sorter' do
134 
+    describe 'declaration' do
135 
+      let(:passive_agent_class) {
136 
+        Class.new(Agent) do
137 
+          include SortableEvents
138 
+
139 
+          cannot_create_events!
140 
+        end
141 
+      }
142 
+
143 
+      let(:active_agent_class) {
144 
+        Class.new(Agent) do
145 
+          include SortableEvents
146 
+        end
147 
+      }
148 
+
149 
+      describe 'can_order_created_events!' do
150 
+        it 'should refuse to work if called from an Agent that cannot create events' do
151 
+          expect {
152 
+            passive_agent_class.class_eval do
153 
+              can_order_created_events!
154 
+            end
155 
+          }.to raise_error
156 
+        end
157 
+
158 
+        it 'should work if called from an Agent that can create events' do
159 
+          expect {
160 
+            active_agent_class.class_eval do
161 
+              can_order_created_events!
162 
+            end
163 
+          }.not_to raise_error
164 
+        end
165 
+      end
166 
+
167 
+      describe 'can_order_created_events?' do
168 
+        it 'should return false unless an Agent declares can_order_created_events!' do
169 
+          expect(active_agent_class.can_order_created_events?).to eq(false)
170 
+          expect(active_agent_class.new.can_order_created_events?).to eq(false)
171 
+        end
172 
+
173 
+        it 'should return true if an Agent declares can_order_created_events!' do
174 
+          active_agent_class.class_eval do
175 
+            can_order_created_events!
176 
+          end
177 
+
178 
+          expect(active_agent_class.can_order_created_events?).to eq(true)
179 
+          expect(active_agent_class.new.can_order_created_events?).to eq(true)
180 
+        end
181 
+      end
182 
+    end
183 
+
184 
+    describe 'behavior' do
185 
+      class Agents::EventOrderableAgent < Agent
186 
+        include SortableEvents
187 
+
188 
+        default_schedule 'never'
189 
+
190 
+        can_order_created_events!
191 
+
192 
+        attr_accessor :payloads_to_emit
193 
+
194 
+        def self.valid_type?(name)
195 
+          true
196 
+        end
197 
+
198 
+        def check
199 
+          payloads_to_emit.each do |payload|
200 
+            create_event payload: payload
201 
+          end
202 
+        end
203 
+
204 
+        def receive(events)
205 
+          events.each do |event|
206 
+            payloads_to_emit.each do |payload|
207 
+              create_event payload: payload.merge('title' => payload['title'] + event.payload['title_suffix'])
208 
+            end
209 
+          end
210 
+        end
211 
+      end
212 
+
213 
+      def new_agent(events_order = nil)
214 
+        options = {}
215 
+        options['events_order'] = events_order if events_order
216 
+        Agents::EventOrderableAgent.new(name: 'test', options: options) { |agent|
217 
+          agent.user = users(:bob)
218 
+          agent.payloads_to_emit = payloads
219 
+        }
220 
+      end
221 
+
222 
+      let(:payloads) {
223 
+        [
224 
+          { 'title' => 'TitleA', 'score' => 4,  'updated_on' => '7 Jul 2015' },
225 
+          { 'title' => 'TitleB', 'score' => 2,  'updated_on' => '25 Jun 2014' },
226 
+          { 'title' => 'TitleD', 'score' => 10, 'updated_on' => '10 Jan 2015' },
227 
+          { 'title' => 'TitleC', 'score' => 10, 'updated_on' => '9 Feb 2015' },
228 
+        ]
229 
+      }
230 
+
231 
+      it 'should keep the order of created events unless events_order is specified' do
232 
+        [[], [nil], [[]]].each do |args|
233 
+          agent = new_agent(*args)
234 
+          agent.save!
235 
+          expect { agent.check }.to change { Event.count }.by(4)
236 
+          events = agent.events.last(4).sort_by(&:id)
237 
+          expect(events.map { |event| event.payload['title'] }).to eq(%w[TitleA TitleB TitleD TitleC])
238 
+        end
239 
+      end
240 
+
241 
+      it 'should sort events created in check() in the order specified in events_order' do
242 
+        agent = new_agent([['{{score}}', 'number'], ['{{title}}', 'string', true]])
243 
+        agent.save!
244 
+        expect { agent.check }.to change { Event.count }.by(4)
245 
+        events = agent.events.last(4).sort_by(&:id)
246 
+        expect(events.map { |event| event.payload['title'] }).to eq(%w[TitleB TitleA TitleD TitleC])
247 
+      end
248 
+
249 
+      it 'should sort events created in receive() in the order specified in events_order' do
250 
+        agent = new_agent([['{{score}}', 'number'], ['{{title}}', 'string', true]])
251 
+        agent.save!
252 
+        expect {
253 
+          agent.receive([Event.new(payload: { 'title_suffix' => ' [new]' }),
254 
+                         Event.new(payload: { 'title_suffix' => ' [popular]' })])
255 
+        }.to change { Event.count }.by(8)
256 
+        events = agent.events.last(8).sort_by(&:id)
257 
+        expect(events.map { |event| event.payload['title'] }).to eq([
258 
+          'TitleB [new]',     'TitleA [new]',     'TitleD [new]',     'TitleC [new]',
259 
+          'TitleB [popular]', 'TitleA [popular]', 'TitleD [popular]', 'TitleC [popular]',
260 
+        ])
261 
+      end
262 
+    end
263 
+  end
264 
+end