Add day_of_week to Time (#329)

REFERENCE.md

@@ -1919,6 +1919,7 @@
 | `date` | 2015-11-08 00:00:00 +0900, 2012-08-27 00:00:00 +0900, 2014-01-31 00:00:00 +0900 |
 | `datetime` | 2013-11-21 12:16:00 +0900, 2012-06-21 08:01:00 +0900, 2012-10-15 05:14:00 +0900 |
 | `month` | July, August, June |
+| `day_of_week` | Mon, Tue, Sat |
 
 ## FFaker::Tweet
 

lib/ffaker/time.rb

@@ -6,11 +6,16 @@ module Time
     extend self
 
     MONTHS = %w(January February March April May June July August September October November December).freeze
+    DAYS_OF_WEEK = %w(Monday Tuesday Wednesday Thursday Friday Saturday Sunday).freeze
 
     def month
       fetch_sample(MONTHS)
     end
 
+    def day_of_week(options = {})
+      fetch_sample(DAYS_OF_WEEK)[0..(options[:long] ? 10 : 2)]
+    end
+
     def date(params = {})
       years_back = params[:year_range] || 5
       latest_year = params [:year_latest] || 0

test/test_time.rb

@@ -5,7 +5,7 @@
 class TestFakerTime < Test::Unit::TestCase
   include DeterministicHelper
 
-  assert_methods_are_deterministic(FFaker::Time, :date, :datetime, :month)
+  assert_methods_are_deterministic(FFaker::Time, :date, :datetime, :month, :day_of_week)
 
   def setup
     @tester = FFaker::Time
@@ -16,6 +16,14 @@ def test_date
     assert_match(date_regex, @tester.date)
   end
 
+  def test_day_of_week
+    day_of_week_short_regex = /\A(?:Mon|Tue|Wed|Thu|Fri|Sat|Sun)\z/
+    day_of_week_long_regex = /\A(?:Monday|Tuesday|Wednesday|Thursday|Friday|Saturday|Sunday)\z/
+    assert_match(day_of_week_short_regex, @tester.day_of_week)
+    assert_match(day_of_week_long_regex, @tester.day_of_week(long: true))
+    assert_deterministic { @tester.day_of_week }
+  end
+
   def test_date_hours_and_minutes
     assert_match('04:20:00', @tester.date(hours: 4, minutes: 20))
     assert_deterministic { @tester.date(hours: 4, minutes: 20) }