Merge pull request #12824 from sikachu/ps-testing-time-helper

Add `#travel` and `#travel_to` to `ActiveSupport::TestCase`

activesupport/CHANGELOG.md

+*   Add `ActiveSupport::Testing::TimeHelpers#travel` and `#travel_to`. These methods change current
+    time to the given time or time difference by stubbing `Time.now` and `Date.today` to return the
+    time or date after the difference calculation, or the time or date that got passed into the
+    method respectively. These methods also accept a block, which will return current time back to
+    its original state at the end of the block.
+
+    Example for `#travel`:
+
+        Time.now # => 2013-11-09 15:34:49 -05:00
+        travel 1.day
+        Time.now # => 2013-11-10 15:34:49 -05:00
+        Date.today # => Sun, 10 Nov 2013
+
+    Example for `#travel_to`:
+
+        Time.now # => 2013-11-09 15:34:49 -05:00
+        travel_to Time.new(2004, 11, 24, 01, 04, 44)
+        Time.now # => 2004-11-24 01:04:44 -05:00
+        Date.today # => Wed, 24 Nov 2004
+
+    Both of these methods also accept a block, which will return the current time back to its
+    original state at the end of the block:
+
+        Time.now # => 2013-11-09 15:34:49 -05:00
+
+        travel 1.day do
+          User.create.created_at # => Sun, 10 Nov 2013 15:34:49 EST -05:00
+        end
+
+        travel_to Time.new(2004, 11, 24, 01, 04, 44) do
+          User.create.created_at # => Wed, 24 Nov 2004 01:04:44 EST -05:00
+        end
+
+        Time.now # => 2013-11-09 15:34:49 -05:00
+
+    This module is included in `ActiveSupport::TestCase` automatically.
+
+    *Prem Sichanugrist*, *DHH*
+
 *   Unify `cattr_*` interface: allow to pass a block to `cattr_reader`.
 
     Example:

activesupport/lib/active_support/test_case.rb

@@ -7,6 +7,7 @@
 require 'active_support/testing/declarative'
 require 'active_support/testing/isolation'
 require 'active_support/testing/constant_lookup'
+require 'active_support/testing/time_helpers'
 require 'active_support/core_ext/kernel/reporting'
 require 'active_support/deprecation'
 
@@ -34,6 +35,7 @@ def self.for_tag(tag)
     include ActiveSupport::Testing::SetupAndTeardown
     include ActiveSupport::Testing::Assertions
     include ActiveSupport::Testing::Deprecation
+    include ActiveSupport::Testing::TimeHelpers
     extend ActiveSupport::Testing::Declarative
 
     # test/unit backwards compatibility methods

activesupport/lib/active_support/testing/time_helpers.rb

+module ActiveSupport
+  module Testing
+    # Containing helpers that helps you test passage of time.
+    module TimeHelpers
+      # Change current time to the time in the future or in the past by a given time difference by
+      # stubbing +Time.now+ and +Date.today+. This method also accepts a block, which will return
+      # 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
+      #   Time.current # => Sun, 10 Nov 2013 15:34:49 EST -05:00
+      #   Date.current # => Sun, 10 Nov 2013
+      #
+      # 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
+      def travel(duration, &block)
+        travel_to Time.now + duration, &block
+      end
+
+      # Change current time to the given time by stubbing +Time.now+ and +Date.today+ to return the
+      # time or date passed into this method. This method also accepts a block, which will return
+      # 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)
+      #   Time.current # => Wed, 24 Nov 2004 01:04:44 EST -05:00
+      #   Date.current # => Wed, 24 Nov 2004
+      #
+      # 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
+      #     User.create.created_at # => Wed, 24 Nov 2004 01:04:44 EST -05:00
+      #   end
+      #   Time.current # => Sat, 09 Nov 2013 15:34:49 EST -05:00
+      def travel_to(date_or_time, &block)
+        Time.stubs now: date_or_time.to_time
+        Date.stubs today: date_or_time.to_date
+
+        if block_given?
+          block.call
+          Time.unstub :now
+          Date.unstub :today
+        end
+      end
+    end
+  end
+end

activesupport/test/test_test.rb

 require 'abstract_unit'
+require 'active_support/core_ext/date'
+require 'active_support/core_ext/numeric/time'
 
 class AssertDifferenceTest < ActiveSupport::TestCase
   def setup
@@ -122,7 +124,6 @@ def sentinel
     end
 end
 
-
 class SubclassSetupAndTeardownTest < SetupAndTeardownTest
   setup :bar
   teardown :bar
@@ -143,7 +144,6 @@ def sentinel
     end
 end
 
-
 class TestCaseTaggedLoggingTest < ActiveSupport::TestCase
   def before_setup
     require 'stringio'
@@ -156,3 +156,49 @@ def test_logs_tagged_with_current_test_case
     assert_match "#{self.class}: #{name}\n", @out.string
   end
 end
+
+class TimeHelperTest < ActiveSupport::TestCase
+  setup do
+    Time.stubs now: Time.now
+  end
+
+  def test_time_helper_travel
+    expected_time = Time.now + 1.day
+    travel 1.day
+
+    assert_equal expected_time, Time.now
+    assert_equal expected_time.to_date, Date.today
+  end
+
+  def test_time_helper_travel_with_block
+    expected_time = Time.now + 1.day
+
+    travel 1.day do
+      assert_equal expected_time, Time.now
+      assert_equal expected_time.to_date, Date.today
+    end
+
+    assert_not_equal expected_time, Time.now
+    assert_not_equal expected_time.to_date, Date.today
+  end
+
+  def test_time_helper_travel_to
+    expected_time = Time.new(2004, 11, 24, 01, 04, 44)
+    travel_to expected_time
+
+    assert_equal expected_time, Time.now
+    assert_equal Date.new(2004, 11, 24), Date.today
+  end
+
+  def test_time_helper_travel_to_with_block
+    expected_time = Time.new(2004, 11, 24, 01, 04, 44)
+
+    travel_to expected_time do
+      assert_equal expected_time, Time.now
+      assert_equal Date.new(2004, 11, 24), Date.today
+    end
+
+    assert_not_equal expected_time, Time.now
+    assert_not_equal Date.new(2004, 11, 24), Date.today
+  end
+end