Add `before?` and `after?` methods to date and time classes

Equality comparisons between dates and times can take some extra time to
comprehend. I tend to think of a date or time as "before" or "after"
another date or time, but I naturally read `<` and `>` as "less than"
and "greater than." This change seeks to make date/time comparisons more
human readable.

9 files changed, 63 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index a7af51f83e..582209c2ae 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,5 +1,10 @@
 ## Rails 6.0.0.alpha (Unreleased) ##
 
+*   Add `before?` and `after?` methods to `Date`, `DateTime`,
+    `Time`, and `TimeWithZone`.
+
+    *Nick Holden*
+
 *   Add `:private` option to ActiveSupport's `Module#delegate`
     in order to delegate methods as private:
 
diff --git a/activesupport/lib/active_support/core_ext/date/calculations.rb b/activesupport/lib/active_support/core_ext/date/calculations.rb
index 1cd7acb05d..e7be5c1376 100644
--- a/activesupport/lib/active_support/core_ext/date/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date/calculations.rb
@@ -142,4 +142,6 @@ class Date
   end
   alias_method :compare_without_coercion, :<=>
   alias_method :<=>, :compare_with_coercion
+  alias_method :before?, :<
+  alias_method :after?, :>
 end
diff --git a/activesupport/lib/active_support/core_ext/date_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
index e61b23f842..eace125883 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -208,4 +208,6 @@ class DateTime
       super
     end
   end
+  alias_method :before?, :<
+  alias_method :after?, :>
 end
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index 120768dec5..0507f9e652 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -302,6 +302,8 @@ class Time
   end
   alias_method :compare_without_coercion, :<=>
   alias_method :<=>, :compare_with_coercion
+  alias_method :before?, :<
+  alias_method :after?, :>
 
   # Layers additional behavior on Time#eql? so that ActiveSupport::TimeWithZone instances
   # can be eql? to an equivalent Time
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index 20650ce714..7e71318404 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -225,6 +225,8 @@ module ActiveSupport
     def <=>(other)
       utc <=> other
     end
+    alias_method :before?, :<
+    alias_method :after?, :>
 
     # Returns true if the current object's time is within the specified
     # +min+ and +max+ time.
diff --git a/activesupport/test/core_ext/date_ext_test.rb b/activesupport/test/core_ext/date_ext_test.rb
index b8652884ce..8d3d575e0f 100644
--- a/activesupport/test/core_ext/date_ext_test.rb
+++ b/activesupport/test/core_ext/date_ext_test.rb
@@ -360,6 +360,18 @@ class DateExtCalculationsTest < ActiveSupport::TestCase
     end
   end
 
+  def test_before
+    assert_equal false, Date.new(2017, 3, 6).before?(Date.new(2017, 3, 5))
+    assert_equal false, Date.new(2017, 3, 6).before?(Date.new(2017, 3, 6))
+    assert_equal true, Date.new(2017, 3, 6).before?(Date.new(2017, 3, 7))
+  end
+
+  def test_after
+    assert_equal true, Date.new(2017, 3, 6).after?(Date.new(2017, 3, 5))
+    assert_equal false, Date.new(2017, 3, 6).after?(Date.new(2017, 3, 6))
+    assert_equal false, Date.new(2017, 3, 6).after?(Date.new(2017, 3, 7))
+  end
+
   def test_current_returns_date_today_when_zone_not_set
     with_env_tz "US/Central" do
       Time.stub(:now, Time.local(1999, 12, 31, 23)) do
diff --git a/activesupport/test/core_ext/date_time_ext_test.rb b/activesupport/test/core_ext/date_time_ext_test.rb
index 894fb80cba..a6124197ae 100644
--- a/activesupport/test/core_ext/date_time_ext_test.rb
+++ b/activesupport/test/core_ext/date_time_ext_test.rb
@@ -285,6 +285,18 @@ class DateTimeExtCalculationsTest < ActiveSupport::TestCase
     end
   end
 
+  def test_before
+    assert_equal false, DateTime.civil(2017, 3, 6, 12, 0, 0).before?(DateTime.civil(2017, 3, 6, 11, 59, 59))
+    assert_equal false, DateTime.civil(2017, 3, 6, 12, 0, 0).before?(DateTime.civil(2017, 3, 6, 12, 0, 0))
+    assert_equal true, DateTime.civil(2017, 3, 6, 12, 0, 0).before?(DateTime.civil(2017, 3, 6, 12, 00, 1))
+  end
+
+  def test_after
+    assert_equal true, DateTime.civil(2017, 3, 6, 12, 0, 0).after?(DateTime.civil(2017, 3, 6, 11, 59, 59))
+    assert_equal false, DateTime.civil(2017, 3, 6, 12, 0, 0).after?(DateTime.civil(2017, 3, 6, 12, 0, 0))
+    assert_equal false, DateTime.civil(2017, 3, 6, 12, 0, 0).after?(DateTime.civil(2017, 3, 6, 12, 00, 1))
+  end
+
   def test_current_returns_date_today_when_zone_is_not_set
     with_env_tz "US/Eastern" do
       Time.stub(:now, Time.local(1999, 12, 31, 23, 59, 59)) do
diff --git a/activesupport/test/core_ext/time_ext_test.rb b/activesupport/test/core_ext/time_ext_test.rb
index e1cb22fda8..0d16e51087 100644
--- a/activesupport/test/core_ext/time_ext_test.rb
+++ b/activesupport/test/core_ext/time_ext_test.rb
@@ -736,6 +736,18 @@ class TimeExtCalculationsTest < ActiveSupport::TestCase
     end
   end
 
+  def test_before
+    assert_equal false, Time.utc(2017, 3, 6, 12, 0, 0).before?(Time.utc(2017, 3, 6, 11, 59, 59))
+    assert_equal false, Time.utc(2017, 3, 6, 12, 0, 0).before?(Time.utc(2017, 3, 6, 12, 0, 0))
+    assert_equal true, Time.utc(2017, 3, 6, 12, 0, 0).before?(Time.utc(2017, 3, 6, 12, 00, 1))
+  end
+
+  def test_after
+    assert_equal true, Time.utc(2017, 3, 6, 12, 0, 0).after?(Time.utc(2017, 3, 6, 11, 59, 59))
+    assert_equal false, Time.utc(2017, 3, 6, 12, 0, 0).after?(Time.utc(2017, 3, 6, 12, 0, 0))
+    assert_equal false, Time.utc(2017, 3, 6, 12, 0, 0).after?(Time.utc(2017, 3, 6, 12, 00, 1))
+  end
+
   def test_acts_like_time
     assert_predicate Time.new, :acts_like_time?
   end
diff --git a/activesupport/test/core_ext/time_with_zone_test.rb b/activesupport/test/core_ext/time_with_zone_test.rb
index 2ea5f0921c..e650209268 100644
--- a/activesupport/test/core_ext/time_with_zone_test.rb
+++ b/activesupport/test/core_ext/time_with_zone_test.rb
@@ -289,6 +289,20 @@ class TimeWithZoneTest < ActiveSupport::TestCase
     end
   end
 
+  def test_before
+    twz = ActiveSupport::TimeWithZone.new(Time.utc(2017, 3, 6, 12, 0, 0), @time_zone)
+    assert_equal false, twz.before?(ActiveSupport::TimeWithZone.new(Time.utc(2017, 3, 6, 11, 59, 59), @time_zone))
+    assert_equal false, twz.before?(ActiveSupport::TimeWithZone.new(Time.utc(2017, 3, 6, 12, 0, 0), @time_zone))
+    assert_equal true, twz.before?(ActiveSupport::TimeWithZone.new(Time.utc(2017, 3, 6, 12, 00, 1), @time_zone))
+  end
+
+  def test_after
+    twz = ActiveSupport::TimeWithZone.new(Time.utc(2017, 3, 6, 12, 0, 0), @time_zone)
+    assert_equal true, twz.after?(ActiveSupport::TimeWithZone.new(Time.utc(2017, 3, 6, 11, 59, 59), @time_zone))
+    assert_equal false, twz.after?(ActiveSupport::TimeWithZone.new(Time.utc(2017, 3, 6, 12, 0, 0), @time_zone))
+    assert_equal false, twz.after?(ActiveSupport::TimeWithZone.new(Time.utc(2017, 3, 6, 12, 00, 1), @time_zone))
+  end
+
   def test_eql?
     assert_equal true, @twz.eql?(@twz.dup)
     assert_equal true, @twz.eql?(Time.utc(2000))