add streak model

lib/seinfeld.rb

@@ -28,7 +28,7 @@ class << self
     attr_reader :logger
   end
 
-  [:Feed].each do |const|
+  [:Feed, :Streak].each do |const|
     autoload const, "seinfeld/#{const.to_s.underscore}"
   end
 

lib/seinfeld/streak.rb

@@ -0,0 +1,52 @@
+class Seinfeld
+  # Represents a consecutive sequence of days that a user has committed.
+  class Streak
+    attr_accessor :started, :ended
+
+    # start - First Date in the sequence that a commit was made.
+    # ended - Last Date (or the current Date) in the sequence that a commit 
+    #         was made.
+    def initialize(started = nil, ended = nil)
+      @started = started
+      @ended   = ended || started
+    end
+
+    # Public: Counts the number of days in the sequence, including the start 
+    # and end.
+    def days
+      if @started && @ended
+        1 + (@ended - @started).to_i.abs
+      else
+        0
+      end
+    end
+
+    # Public: Checks if the streak is current.  Allow streaks from yesterday 
+    # to count, Seinfeld is confident the user will commit in time to keep 
+    # the streak.
+    #
+    # date - The Date that we are checking against.  (default: Date.today)
+    #
+    # Returns true if the Streak is current, and false if it isn't.
+    def current?(date = Date.today)
+      @ended && (@ended + 1) >= date
+    end
+
+    # Public: Checks if the given date is included in the sequence.
+    #
+    # date - The Date that we are checking.
+    #
+    # Returns true if the date is in the Streak, and false if it isn't.
+    def include?(date)
+      if @started && @ended
+        @started <= date && @ended >= date
+      else
+        false
+      end
+    end
+
+    def inspect
+      %(#{@started ? ("#{@started.year}-#{@started.month}-#{@started.day}") : :nil}..#{@ended ? ("#{@ended.year}-#{@ended.month}-#{@ended.day}") : :nil}:Streak)
+    end
+  end
+end

test/streak_test.rb

@@ -0,0 +1,61 @@
+require File.join(File.dirname(__FILE__), "test_helper")
+
+class StreakTest < ActiveSupport::TestCase
+  setup_once do
+    @today         = Date.today
+    @new_streak    = Seinfeld::Streak.new
+    @same_streak   = Seinfeld::Streak.new(Date.civil(2008, 1, 5))
+    @set_streak    = Seinfeld::Streak.new(Date.civil(2007, 12, 31), Date.civil(2008, 1, 5))
+    @today_streak  = Seinfeld::Streak.new(@today - 4, @today)
+    @yester_streak = Seinfeld::Streak.new(@today - 5, @today-1)
+    @old_streak    = Seinfeld::Streak.new(@today - 6, @today-2)
+  end
+
+  test "has 0 days with neither bounds set" do
+    assert_equal 0, @new_streak.days
+  end
+
+  test "does not include outside date with neither bounds set" do
+    assert !@new_streak.include?(@today)
+  end
+
+  test "is not current with neither bounds set" do
+    assert !@new_streak.current?
+  end
+
+  test "has 1 day with @started and @ended set on the same day" do
+    assert_equal 1, @same_streak.days
+  end
+
+  test "does not include outside date with @started and @ended set on the same day" do
+    assert !@same_streak.include?(@today)
+  end
+
+  test "is not current with @started and @ended set on the same day" do
+    assert !@same_streak.current?
+  end
+
+  test "has 5 days with @started and @ended set, ending today" do
+    assert_equal 5, @today_streak.days
+  end
+
+  test "is current with @started and @ended set, ending today" do
+    assert @today_streak.current?
+  end
+
+  test "has 5 days with @started and @ended set, ending yestertoday" do
+    assert_equal 5, @yester_streak.days
+  end
+
+  test "is current with @started and @ended set, ending yestertoday" do
+    assert @yester_streak.current?
+  end
+
+  test "has 5 days with @started and @ended set, ending 2 days ago" do
+    assert_equal 5, @old_streak.days
+  end
+
+  test "is not current with @started and @ended set, ending 2 days ago" do
+    assert !@old_streak.current?
+  end
+end