Add additional tests for #27610

Since 1.month no longer equals 30.days add some tests to ensure that
addition maintains the same day in the month or is the last day in
the month if the month has less days than the current day. Also add
a test for the behaviour of 12.months == 1.year.

1 files changed, 38 insertions, 1 deletions

diff --git a/activesupport/test/core_ext/duration_test.rb b/activesupport/test/core_ext/duration_test.rb
index 8c4c08ffd4..6a275d1d5b 100644
--- a/activesupport/test/core_ext/duration_test.rb
+++ b/activesupport/test/core_ext/duration_test.rb
@@ -237,6 +237,29 @@ class DurationTest < ActiveSupport::TestCase
     assert_equal(1, (61 <=> 1.minute))
   end
 
+  def test_twelve_months_equals_one_year
+    assert_equal 12.months, 1.year
+  end
+
+  def test_thirty_days_does_not_equal_one_month
+    assert_not_equal 30.days, 1.month
+  end
+
+  def test_adding_one_month_maintains_day_of_month
+    (1..11).each do |month|
+      [1, 14, 28].each do |day|
+        assert_equal Date.civil(2016, month + 1, day), Date.civil(2016, month, day) + 1.month
+      end
+    end
+
+    assert_equal Date.civil(2017, 1, 1),  Date.civil(2016, 12, 1) + 1.month
+    assert_equal Date.civil(2017, 1, 14),  Date.civil(2016, 12, 14) + 1.month
+    assert_equal Date.civil(2017, 1, 28),  Date.civil(2016, 12, 28) + 1.month
+
+    assert_equal Date.civil(2015, 2, 28), Date.civil(2015, 1, 31) + 1.month
+    assert_equal Date.civil(2016, 2, 29), Date.civil(2016, 1, 31) + 1.month
+  end
+
   # ISO8601 string examples are taken from ISO8601 gem at https://github.com/arnau/ISO8601/blob/b93d466840/spec/iso8601/duration_spec.rb
   # published under the conditions of MIT license at https://github.com/arnau/ISO8601/blob/b93d466840/LICENSE
   #
@@ -340,12 +363,26 @@ class DurationTest < ActiveSupport::TestCase
         travel_to Time.utc(2016, 11, 4) do
           assert_equal 604800, ActiveSupport::Duration.parse("P7D").to_i
           assert_equal 604800, ActiveSupport::Duration.parse("P1W").to_i
-          assert_equal ActiveSupport::Duration.parse(3.years.iso8601).to_i, 3.years.to_i
         end
       end
     end
   end
 
+  def test_iso8601_parsing_equivalence_with_numeric_extensions_over_long_periods
+    with_env_tz eastern_time_zone do
+      with_tz_default "Eastern Time (US & Canada)" do
+        assert_equal 3.months, ActiveSupport::Duration.parse("P3M")
+        assert_equal 3.months.to_i, ActiveSupport::Duration.parse("P3M").to_i
+        assert_equal 10.months, ActiveSupport::Duration.parse("P10M")
+        assert_equal 10.months.to_i, ActiveSupport::Duration.parse("P10M").to_i
+        assert_equal 3.years, ActiveSupport::Duration.parse("P3Y")
+        assert_equal 3.years.to_i, ActiveSupport::Duration.parse("P3Y").to_i
+        assert_equal 10.years, ActiveSupport::Duration.parse("P10Y")
+        assert_equal 10.years.to_i, ActiveSupport::Duration.parse("P10Y").to_i
+      end
+    end
+  end
+
   def test_adding_durations_do_not_hold_prior_states
     time = Time.parse("Nov 29, 2016")
     # If the implementation adds and subtracts 3 months, the