Module: ActiveSupport::Testing::TimeHelpers

Included in:
ActiveSupport::TestCase
Defined in:
lib/active_support/testing/time_helpers.rb

Overview

Contains helpers that help you test passage of time.

Instance Method Summary collapse

Instance Method Details

#travel(duration, &block) ⇒ Object

Changes current time to the time in the future or in the past by a given time difference by stubbing Time.now, Date.today, and DateTime.now.

Time.current     # => Sat, 09 Nov 2013 15:34:49 EST -05:00
travel 1.day
Time.current     # => Sun, 10 Nov 2013 15:34:49 EST -05:00
Date.current     # => Sun, 10 Nov 2013
DateTime.current # => Sun, 10 Nov 2013 15:34:49 -0500

This method also accepts a block, which will return the current time back to its original state at the end of the block:

Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
travel 1.day do
  User.create.created_at # => Sun, 10 Nov 2013 15:34:49 EST -05:00
end
Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00



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# File 'lib/active_support/testing/time_helpers.rb', line 69

def travel(duration, &block)
  travel_to Time.now + duration, &block
end

#travel_back ⇒ Object

Returns the current time back to its original state, by removing the stubs added by ‘travel` and `travel_to`.

Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
travel_to Time.zone.local(2004, 11, 24, 01, 04, 44)
Time.current # => Wed, 24 Nov 2004 01:04:44 EST -05:00
travel_back
Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00



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# File 'lib/active_support/testing/time_helpers.rb', line 159

def travel_back
  simple_stubs.unstub_all!
end

#travel_to(date_or_time) ⇒ Object

Changes current time to the given time by stubbing Time.now, Date.today, and DateTime.now to return the time or date passed into this method.

Time.current     # => Sat, 09 Nov 2013 15:34:49 EST -05:00
travel_to Time.zone.local(2004, 11, 24, 01, 04, 44)
Time.current     # => Wed, 24 Nov 2004 01:04:44 EST -05:00
Date.current     # => Wed, 24 Nov 2004
DateTime.current # => Wed, 24 Nov 2004 01:04:44 -0500

Dates are taken as their timestamp at the beginning of the day in the application time zone. Time.current returns said timestamp, and Time.now its equivalent in the system time zone. Similarly, Date.current returns a date equal to the argument, and Date.today the date according to Time.now, which may be different. (Note that you rarely want to deal with Time.now, or Date.today, in order to honor the application time zone please always use Time.current and Date.current.)

Note that the usec for the time passed will be set to 0 to prevent rounding errors with external services, like MySQL (which will round instead of floor, leading to off-by-one-second errors).

This method also accepts a block, which will return the current time back to its original state at the end of the block:

Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
travel_to Time.zone.local(2004, 11, 24, 01, 04, 44) do
  Time.current # => Wed, 24 Nov 2004 01:04:44 EST -05:00
end
Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00



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# File 'lib/active_support/testing/time_helpers.rb', line 103

def travel_to(date_or_time)
  if block_given? && simple_stubs.stubbing(Time, :now)
    travel_to_nested_block_call = <<-MSG.strip_heredoc

Calling `travel_to` with a block, when we have previously already made a call to `travel_to`, can lead to confusing time stubbing.

Instead of:

   travel_to 2.days.from_now do
     # 2 days from today
     travel_to 3.days.from_now do
       # 5 days from today
     end
   end

preferred way to achieve above is:

   travel 2.days do
     # 2 days from today
   end

   travel 5.days do
     # 5 days from today
   end

    MSG
    raise travel_to_nested_block_call
  end

  if date_or_time.is_a?(Date) && !date_or_time.is_a?(DateTime)
    now = date_or_time.midnight.to_time
  else
    now = date_or_time.to_time.change(usec: 0)
  end

  simple_stubs.stub_object(Time, :now) { at(now.to_i) }
  simple_stubs.stub_object(Date, :today) { jd(now.to_date.jd) }
  simple_stubs.stub_object(DateTime, :now) { jd(now.to_date.jd, now.hour, now.min, now.sec, Rational(now.utc_offset, 86400)) }

  if block_given?
    begin
      yield
    ensure
      travel_back
    end
  end
end