DateTime Problem in Rails Unit Tests

Question

I'm working on unit tests for my Rails app and have run into the following problem.

I have an Event model with a fixture that boils down to:

concert:
  name:        Wallflowers
  start_at:    <%= DateTime.new(1999) %>

In my unit test, I have the following assertion:

assert_equal DateTime.new(1999), events(:concert).start_at

The test fails, with the following message:

<Fri, 01 Jan 1999 00:00:00 +0000> expected but was
<Thu, 31 Dec 1998 19:00:00 UTC +00:00>.

I can't figure out why its getting adjusted. The offset of the incorrect time is 5 hours, which is my local offset.

Other info that might be relevant:

• The problem only occurs while testing--I don't have any problems in development
• environment.rb contains config.time_zone = 'UTC'
• The test works if I use Date.new instead of DateTime.new, but I need to use DateTime

What am I missing? Appreciate the help.

Answer 1

Change it to this

concert:
  name: Wallflowers
  start_at: <%= DateTime.new(1999).to_s(:db) %>

Answer 2

ActiveRecord automatically converts all inserted timestamps to UTC. This explains why your concert time is adjusted to a different timezone. The first step would be to see if the problem is solved by you setting your config.time_zone in environment.rb to your timezone.

If that doesn't solve the issue, read on:

After some testing, I discovered that there seems to be some discrepancy with using DateTime in fixtures compared to the same code in a controller. If I used DateTime.new(1999) in my controller, the inserted column was 1999-01-01 00:00:00. If I used the same call in my fixture, the inserted column was 1999-01-01 10:30:00, which is my timezone. This was regardless of what config.time_zone was set to.

In both cases, changing the timezone correctly changed the ActiveRecord object fetched from the database.

In truth, I don't know which is the correct representation. I do know that the test passed when I changed the fixture to '1999-01-01 00:00' instead of using DateTime.new(1999). If the solution in the first paragraph doesn't work for you, try changing the fixture to the string representation of the date.