Refactor Date/Time next_occurring and prev_occurring

These methods were originally added in https://github.com/rails/rails/pull/26600

This includes a couple of refactors to make these methods behave more similarly to other Date/Time extensions added by Active Support:

1. Use `advance` instead of `since` and `ago` to time-travel — this is particularly important to keep the returned instance’s class matching `self`.  Before this change:

    today = Date.today                     # => Tue, 28 Nov 2017
    today.class                            # => Date
    today.next_occurring(:wednesday)       # => Wed, 29 Nov 2017 00:00:00 UTC +00:00
    today.next_occurring(:wednesday).class # => ActiveSupport::TimeWithZone

  After this change, a Date (or Time, or DateTime) instance is properly returned (just like is shown in the new docs).  This is generally how everything else in DateAndTime::Calculations works.

2. Move the tests from the DateTime tests to the DateAndTimeBehavior tests.  The latter location is mixed in to the core_ext tests for _all_ of Date, Time, and DateTime to test the behavior across all of the classes.  The previous location is for testing core_ext functionality added specifically just to DateTime.

3. Better docs!

1 files changed, 0 insertions, 22 deletions

diff --git a/activesupport/test/core_ext/date_time_ext_test.rb b/activesupport/test/core_ext/date_time_ext_test.rb
index d942cddb2a..ed962803fa 100644
--- a/activesupport/test/core_ext/date_time_ext_test.rb
+++ b/activesupport/test/core_ext/date_time_ext_test.rb
@@ -30,28 +30,6 @@ class DateTimeExtCalculationsTest < ActiveSupport::TestCase
     end
   end
 
-  def test_next_occur
-    datetime = DateTime.new(2016, 9, 24, 0, 0) # saturday
-    assert_equal datetime.next_occurring(:monday), datetime.since(2.days)
-    assert_equal datetime.next_occurring(:tuesday), datetime.since(3.days)
-    assert_equal datetime.next_occurring(:wednesday), datetime.since(4.days)
-    assert_equal datetime.next_occurring(:thursday), datetime.since(5.days)
-    assert_equal datetime.next_occurring(:friday), datetime.since(6.days)
-    assert_equal datetime.next_occurring(:saturday), datetime.since(1.week)
-    assert_equal datetime.next_occurring(:sunday), datetime.since(1.day)
-  end
-
-  def test_prev_occur
-    datetime = DateTime.new(2016, 9, 24, 0, 0) # saturday
-    assert_equal datetime.prev_occurring(:monday), datetime.ago(5.days)
-    assert_equal datetime.prev_occurring(:tuesday), datetime.ago(4.days)
-    assert_equal datetime.prev_occurring(:wednesday), datetime.ago(3.days)
-    assert_equal datetime.prev_occurring(:thursday), datetime.ago(2.days)
-    assert_equal datetime.prev_occurring(:friday), datetime.ago(1.day)
-    assert_equal datetime.prev_occurring(:saturday), datetime.ago(1.week)
-    assert_equal datetime.prev_occurring(:sunday), datetime.ago(6.days)
-  end
-
   def test_readable_inspect
     datetime = DateTime.new(2005, 2, 21, 14, 30, 0)
     assert_equal "Mon, 21 Feb 2005 14:30:00 +0000", datetime.readable_inspect