Fix rounding problem for PostgreSQL timestamp column

If timestamp column have the precision, it need to format according to
the precision of timestamp column.

1 files changed, 16 insertions, 0 deletions

diff --git a/activerecord/test/cases/adapters/postgresql/timestamp_test.rb b/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
index eb32c4d2c2..8246b14b93 100644
--- a/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/timestamp_test.rb
@@ -46,6 +46,8 @@ end
 class TimestampTest < ActiveRecord::TestCase
   fixtures :topics
 
+  class Foo < ActiveRecord::Base; end
+
   def test_group_by_date
     keys = Topic.group("date_trunc('month', created_at)").count.keys
     assert_operator keys.length, :>, 0
@@ -135,6 +137,20 @@ class TimestampTest < ActiveRecord::TestCase
     assert_equal date, Developer.find_by_name("yahagi").updated_at
   end
 
+  def test_formatting_timestamp_according_to_precision
+    ActiveRecord::Base.connection.create_table(:foos, force: true) do |t|
+      t.datetime :created_at, precision: 0
+      t.datetime :updated_at, precision: 4
+    end
+    date = ::Time.utc(2014, 8, 17, 12, 30, 0, 999999)
+    Foo.create!(created_at: date, updated_at: date)
+    assert foo = Foo.find_by(created_at: date)
+    assert_equal date.to_s, foo.created_at.to_s
+    assert_equal date.to_s, foo.updated_at.to_s
+    assert_equal 000000, foo.created_at.usec
+    assert_equal 999900, foo.updated_at.usec
+  end
+
   private
 
   def pg_datetime_precision(table_name, column_name)