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Module: ActiveSupport::Testing::TimeHelpers

Overview

Containing helpers that helps you test passage of time.

Instance Method Summary

  • #travel(duration, &block)

    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.

  • #travel_back

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

  • #travel_to(date_or_time)

    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.

Instance Method Details

#travel(duration, &block)

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
[ GitHub ]

  
# File 'activesupport/lib/active_support/testing/time_helpers.rb', line 61

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

#travel_back

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.new(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
[ GitHub ]

  
# File 'activesupport/lib/active_support/testing/time_helpers.rb', line 123

def travel_back
  simple_stubs.unstub_all!
end

#travel_to(date_or_time)

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.new(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.new(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
[ GitHub ]

  
# File 'activesupport/lib/active_support/testing/time_helpers.rb', line 95

def travel_to(date_or_time)
  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