diff --git a/app/controllers/account_controller.rb b/app/controllers/account_controller.rb
index cc7ff02bb..39afd6157 100644
--- a/app/controllers/account_controller.rb
+++ b/app/controllers/account_controller.rb
@@ -441,7 +441,7 @@ class AccountController < ApplicationController
   def register_automatically(user, &block)
     # Automatic activation
     user.activate
-    user.last_login_on = Time.now
+    user.last_login_on = Time.current
     if user.save
       self.logged_user = user
       flash[:notice] = l(:notice_account_activated)
diff --git a/app/controllers/activities_controller.rb b/app/controllers/activities_controller.rb
index 76bce9875..1597a26d1 100644
--- a/app/controllers/activities_controller.rb
+++ b/app/controllers/activities_controller.rb
@@ -55,7 +55,7 @@ class ActivitiesController < ApplicationController
       end
     end
 
-    events = @activity.events(@date_from, @date_to)
+    events = @activity.events(@date_from.beginning_of_day, @date_to.end_of_day)
 
     if events.empty? || stale?(:etag => [@activity.scope, @date_to, @date_from, @with_subprojects, @author, events.first, events.size, User.current, current_language])
       respond_to do |format|
diff --git a/app/models/query.rb b/app/models/query.rb
index ae852d8fb..d6293950e 100644
--- a/app/models/query.rb
+++ b/app/models/query.rb
@@ -1454,35 +1454,40 @@ class Query < ActiveRecord::Base
   end
 
   def date_for_user_time_zone(y, m, d)
-    if tz = User.current.time_zone
-      tz.local y, m, d
-    else
-      Time.local y, m, d
-    end
+    (User.current.time_zone || Time.current.time_zone).local y, m, d
   end
 
   # Returns a SQL clause for a date or datetime field.
   def date_clause(table, field, from, to, is_custom_filter)
+    field_type = Module.const_get("#{table}".classify).columns_hash["#{field}"].type rescue nil
     s = []
-    if from
-      if from.is_a?(Date)
-        from = date_for_user_time_zone(from.year, from.month, from.day).yesterday.end_of_day
-      else
-        from = from - 1 # second
-      end
-      if self.class.default_timezone == :utc
-        from = from.utc
-      end
-      s << ("#{table}.#{field} > '%s'" % [quoted_time(from, is_custom_filter)])
-    end
-    if to
-      if to.is_a?(Date)
-        to = date_for_user_time_zone(to.year, to.month, to.day).end_of_day
+    if field_type == :date
+      {
+        :from => from,
+        :to => to,
+      }.each do |key, val|
+        next unless val
+        val = val.to_date
+        s << ("#{table}.#{field} #{key == :from ? '>=' : '<='} '%s'" % [self.class.connection.quoted_date(val)])
       end
-      if self.class.default_timezone == :utc
-        to = to.utc
+    else
+      {
+        :from => from,
+        :to => to,
+      }.each do |key, val|
+        next unless val
+        if val.is_a?(Date)
+          val = date_for_user_time_zone(val.year, val.month, val.day)
+          val = val.yesterday if key == :from
+          val = val.end_of_day
+        else
+          val = val + (key == :from ? -1 : 0) # second
+        end
+        if self.class.default_timezone == :utc
+          val = val.utc
+        end
+        s << ("#{table}.#{field} #{key == :from ? '>' : '<='} '%s'" % [quoted_time(val, is_custom_filter)])
       end
-      s << ("#{table}.#{field} <= '%s'" % [quoted_time(to, is_custom_filter)])
     end
     s.join(' AND ')
   end
diff --git a/app/models/setting.rb b/app/models/setting.rb
index e71a9a0cf..a7938973f 100644
--- a/app/models/setting.rb
+++ b/app/models/setting.rb
@@ -93,7 +93,7 @@ class Setting < ActiveRecord::Base
 
   # Hash used to cache setting values
   @cached_settings = {}
-  @cached_cleared_on = Time.now
+  @cached_cleared_on = Time.current
 
   def value
     v = read_attribute(:value)
@@ -269,7 +269,7 @@ class Setting < ActiveRecord::Base
   # Clears the settings cache
   def self.clear_cache
     @cached_settings.clear
-    @cached_cleared_on = Time.now
+    @cached_cleared_on = Time.current
     logger.info "Settings cache cleared." if logger
   end
 
diff --git a/app/models/token.rb b/app/models/token.rb
index e34d6b65e..a66d98a9c 100644
--- a/app/models/token.rb
+++ b/app/models/token.rb
@@ -67,7 +67,7 @@ class Token < ActiveRecord::Base
     end
 
     if validity_time
-      Time.now - validity_time
+      Time.current - validity_time
     end
   end
 
diff --git a/app/models/user.rb b/app/models/user.rb
index d905aa1b3..821ececd9 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -342,7 +342,7 @@ class User < Principal
   def salt_password(clear_password)
     self.salt = User.generate_salt
     self.hashed_password = User.hash_password("#{salt}#{User.hash_password clear_password}")
-    self.passwd_changed_on = Time.now.change(:usec => 0)
+    self.passwd_changed_on = Time.current.change(:usec => 0)
   end
 
   # Does the backend storage allow this user to change their password?
@@ -405,7 +405,7 @@ class User < Principal
   end
 
   def time_zone
-    @time_zone ||= (self.pref.time_zone.blank? ? nil : ActiveSupport::TimeZone[self.pref.time_zone])
+    @time_zone ||= (self.pref.time_zone.blank? ? Time.current.time_zone : ActiveSupport::TimeZone[self.pref.time_zone])
   end
 
   def force_default_language?
@@ -567,11 +567,7 @@ class User < Principal
 
   # Returns the current day according to user's time zone
   def today
-    if time_zone.nil?
-      Date.today
-    else
-      time_zone.today
-    end
+    time_zone&.today || Date.current
   end
 
   # Returns the day of +time+ according to user's time zone
@@ -580,11 +576,7 @@ class User < Principal
   end
 
   def convert_time_to_user_timezone(time)
-    if self.time_zone
-      time.in_time_zone(self.time_zone)
-    else
-      time.utc? ? time.localtime : time
-    end
+    time.in_time_zone(self.time_zone || Time.current.time_zone)
   end
 
   def logged?
diff --git a/app/views/common/feed.atom.builder b/app/views/common/feed.atom.builder
index 023c15601..f90983fbe 100644
--- a/app/views/common/feed.atom.builder
+++ b/app/views/common/feed.atom.builder
@@ -9,7 +9,7 @@ xml.feed "xmlns" => "http://www.w3.org/2005/Atom" do
   xml.link    "rel" => "alternate", "href" => url_for(:params => request.query_parameters.merge(:format => nil, :key => nil), :only_path => false, :protocol => protocol, :host => host)
   xml.id      home_url
   xml.icon    favicon_url
-  xml.updated((@items.first ? @items.first.event_datetime : Time.now).xmlschema)
+  xml.updated((@items.first ? @items.first.event_datetime : Time.current).xmlschema)
   xml.author  { xml.name "#{Setting.app_title}" }
   xml.generator(:uri => Redmine::Info.url) { xml.text! Redmine::Info.app_name; }
   @items.each do |item|
diff --git a/app/views/journals/index.builder b/app/views/journals/index.builder
index 45839ed97..2d39d7e72 100644
--- a/app/views/journals/index.builder
+++ b/app/views/journals/index.builder
@@ -7,7 +7,7 @@ xml.feed "xmlns" => "http://www.w3.org/2005/Atom" do
   xml.link    "rel" => "alternate", "href" => home_url
   xml.id      home_url
   xml.icon    favicon_url
-  xml.updated((@journals.first ? @journals.first.event_datetime : Time.now).xmlschema)
+  xml.updated((@journals.first ? @journals.first.event_datetime : Time.current).xmlschema)
   xml.author  { xml.name "#{Setting.app_title}" }
   @journals.each do |change|
     issue = change.issue
diff --git a/lib/redmine/database.rb b/lib/redmine/database.rb
index 073bdf4ba..44484bd47 100644
--- a/lib/redmine/database.rb
+++ b/lib/redmine/database.rb
@@ -76,16 +76,19 @@ module Redmine
       def timestamp_to_date(column, time_zone)
         if postgresql?
           if time_zone
-            identifier = ActiveSupport::TimeZone.find_tzinfo(time_zone.name).identifier
-            "(#{column}::timestamptz AT TIME ZONE '#{identifier}')::date"
+            offset_tz = time_zone.utc_offset
+            offset_default =
+              Time.now.__send__(ActiveRecord::Base.default_timezone == :utc ? :utc : :localtime).utc_offset
+            "(#{column} + INTERVAL '#{offset_tz - offset_default} SECOND')::date"
           else
             "#{column}::date"
           end
         elsif mysql?
           if time_zone
-            user_identifier = ActiveSupport::TimeZone.find_tzinfo(time_zone.name).identifier
-            local_identifier = ActiveSupport::TimeZone.find_tzinfo(Time.zone.name).identifier
-            "DATE(CONVERT_TZ(#{column},'#{local_identifier}', '#{user_identifier}'))"
+            offset_tz = time_zone.utc_offset
+            offset_default =
+              Time.now.__send__(ActiveRecord::Base.default_timezone == :utc ? :utc : :localtime).utc_offset
+            "DATE(#{column} + INTERVAL #{offset_tz - offset_default} SECOND)"
           else
             "DATE(#{column})"
           end
diff --git a/test/fixtures/issues.yml b/test/fixtures/issues.yml
index 1c2c37fa5..72a490e60 100644
--- a/test/fixtures/issues.yml
+++ b/test/fixtures/issues.yml
@@ -111,7 +111,7 @@ issues_006:
   assigned_to_id:
   author_id: 2
   status_id: 1
-  start_date: <%= Date.today.to_s(:db) %>
+  start_date: <%= Date.current.to_s(:db) %>
   due_date: <%= 1.days.from_now.to_date.to_s(:db) %>
   root_id: 6
   lft: 1
@@ -131,7 +131,7 @@ issues_007:
   author_id: 2
   status_id: 1
   start_date: <%= 10.days.ago.to_s(:db) %>
-  due_date: <%= Date.today.to_s(:db) %>
+  due_date: <%= Date.current.to_s(:db) %>
   lock_version: 0
   root_id: 7
   lft: 1
@@ -171,7 +171,7 @@ issues_009:
   assigned_to_id:
   author_id: 2
   status_id: 1
-  start_date: <%= Date.today.to_s(:db) %>
+  start_date: <%= Date.current.to_s(:db) %>
   due_date: <%= 1.days.from_now.to_date.to_s(:db) %>
   root_id: 9
   lft: 1
@@ -190,7 +190,7 @@ issues_010:
   assigned_to_id:
   author_id: 2
   status_id: 1
-  start_date: <%= Date.today.to_s(:db) %>
+  start_date: <%= Date.current.to_s(:db) %>
   due_date: <%= 1.days.from_now.to_date.to_s(:db) %>
   root_id: 10
   lft: 1
diff --git a/test/functional/issues_controller_test.rb b/test/functional/issues_controller_test.rb
index 62d4894c3..bc6519d77 100644
--- a/test/functional/issues_controller_test.rb
+++ b/test/functional/issues_controller_test.rb
@@ -408,12 +408,10 @@ class IssuesControllerTest < Redmine::ControllerTest
   end
 
   def test_index_grouped_by_created_on_if_time_zone_is_utc
-    # TODO: test fails with mysql
-    skip if mysql?
     skip unless IssueQuery.new.groupable_columns.detect {|c| c.name == :created_on}
-
-    @request.session[:user_id] = 2
-    User.find(2).pref.update(time_zone: 'UTC')
+    current_user = User.find(2)
+    @request.session[:user_id] = current_user.id
+    current_user.pref.update(time_zone: 'UTC')
 
     get(
       :index,
@@ -424,7 +422,8 @@ class IssuesControllerTest < Redmine::ControllerTest
     )
     assert_response :success
 
-    assert_select 'tr.group span.name', :text => '07/19/2006' do
+    group_name = format_date(current_user.convert_time_to_user_timezone(issues(:issues_002).created_on))
+    assert_select 'tr.group span.name', :text => group_name do
       assert_select '+ span.count', :text => '2'
     end
   end
@@ -444,8 +443,7 @@ class IssuesControllerTest < Redmine::ControllerTest
     )
     assert_response :success
 
-    # group_name depends on localtime
-    group_name = format_date(Issue.second.created_on.localtime)
+    group_name = format_date(current_user.convert_time_to_user_timezone(issues(:issues_002).created_on))
     assert_select 'tr.group span.name', :text => group_name do
       assert_select '+ span.count', :text => '2'
     end
@@ -3381,7 +3379,7 @@ class IssuesControllerTest < Redmine::ControllerTest
       )
       assert_response :success
       assert_select 'input[name=?][value=?]', 'issue[start_date]',
-                    Date.today.to_s
+                    Date.current.to_s
     end
   end
 
@@ -3831,7 +3829,7 @@ class IssuesControllerTest < Redmine::ControllerTest
                            :id => Issue.last.id
       issue = Issue.find_by_subject('This is the test_new issue')
       assert_not_nil issue
-      assert_equal Date.today, issue.start_date
+      assert_equal Date.current, issue.start_date
     end
   end
 
diff --git a/test/helpers/application_helper_test.rb b/test/helpers/application_helper_test.rb
index 31575c4ac..e06cf3d93 100644
--- a/test/helpers/application_helper_test.rb
+++ b/test/helpers/application_helper_test.rb
@@ -1505,13 +1505,13 @@ class ApplicationHelperTest < Redmine::HelperTest
 
   def test_due_date_distance_in_words
     to_test = {
-      Date.today => 'Due in 0 days',
-      Date.today + 1 => 'Due in 1 day',
-      Date.today + 100 => 'Due in about 3 months',
-      Date.today + 20000 => 'Due in over 54 years',
-      Date.today - 1 => '1 day late',
-      Date.today - 100 => 'about 3 months late',
-      Date.today - 20000 => 'over 54 years late',
+      Date.current => 'Due in 0 days',
+      Date.current + 1 => 'Due in 1 day',
+      Date.current + 100 => 'Due in about 3 months',
+      Date.current + 20000 => 'Due in over 54 years',
+      Date.current - 1 => '1 day late',
+      Date.current - 100 => 'about 3 months late',
+      Date.current - 20000 => 'over 54 years late',
     }
     ::I18n.locale = :en
     to_test.each do |date, expected|
diff --git a/test/helpers/settings_helper_test.rb b/test/helpers/settings_helper_test.rb
index 985be1f63..0297e7a08 100644
--- a/test/helpers/settings_helper_test.rb
+++ b/test/helpers/settings_helper_test.rb
@@ -24,9 +24,9 @@ class SettingsHelperTest < Redmine::HelperTest
   include ERB::Util
 
   def test_date_format_setting_options_should_include_human_readable_format
-    Date.stubs(:today).returns(Date.parse("2015-07-14"))
-
-    options = date_format_setting_options('en')
-    assert_include ["2015-07-14 (yyyy-mm-dd)", "%Y-%m-%d"], options
+    travel_to Date.parse("2015-07-14") do
+      options = date_format_setting_options('en')
+      assert_include ["2015-07-14 (yyyy-mm-dd)", "%Y-%m-%d"], options
+    end
   end
 end
diff --git a/test/unit/lib/redmine/helpers/gantt_test.rb b/test/unit/lib/redmine/helpers/gantt_test.rb
index e4e8cc6a9..fd907bd29 100644
--- a/test/unit/lib/redmine/helpers/gantt_test.rb
+++ b/test/unit/lib/redmine/helpers/gantt_test.rb
@@ -37,7 +37,7 @@ class Redmine::Helpers::GanttHelperTest < Redmine::HelperTest
   end
 
   def today
-    @today ||= Date.today
+    @today ||= Date.current
   end
   private :today
 
@@ -364,7 +364,7 @@ class Redmine::Helpers::GanttHelperTest < Redmine::HelperTest
     create_gantt
     [gantt_start - 1, gantt_start].each do |start_date|
       @output_buffer = @gantt.line(start_date, gantt_start, 30, false, 'line', :format => :html, :zoom => 4)
-      # the leftmost date (Date.today - 14 days)
+      # the leftmost date (Date.current - 14 days)
       assert_select 'div.task_todo[style*="left:0px"]', 1, @output_buffer
       assert_select 'div.task_todo[style*="width:2px"]', 1, @output_buffer
     end
@@ -374,7 +374,7 @@ class Redmine::Helpers::GanttHelperTest < Redmine::HelperTest
     create_gantt
     [gantt_end, gantt_end + 1].each do |end_date|
       @output_buffer = @gantt.line(gantt_end, end_date, 30, false, 'line', :format => :html, :zoom => 4)
-      # the rightmost date (Date.today + 14 days)
+      # the rightmost date (Date.current + 14 days)
       assert_select 'div.task_todo[style*="left:112px"]', 1, @output_buffer
       assert_select 'div.task_todo[style*="width:2px"]', 1, @output_buffer
     end
diff --git a/test/unit/lib/redmine/i18n_test.rb b/test/unit/lib/redmine/i18n_test.rb
index 5e80eb388..dbb00677b 100644
--- a/test/unit/lib/redmine/i18n_test.rb
+++ b/test/unit/lib/redmine/i18n_test.rb
@@ -88,40 +88,40 @@ class Redmine::I18nTest < ActiveSupport::TestCase
 
   def test_time_format
     set_language_if_valid 'en'
-    now = Time.parse('2011-02-20 15:45:22')
+    now = Time.zone.parse('2011-02-20 15:45:22')
     with_settings :time_format => '%H:%M' do
       with_settings :date_format => '' do
-        assert_equal '02/20/2011 15:45', format_time(now)
-        assert_equal '15:45', format_time(now, false)
+        assert_equal now.strftime('%m/%d/%Y %H:%M'), format_time(now)
+        assert_equal now.strftime('%H:%M'), format_time(now, false)
       end
       with_settings :date_format => '%Y-%m-%d' do
-        assert_equal '2011-02-20 15:45', format_time(now)
-        assert_equal '15:45', format_time(now, false)
+        assert_equal now.strftime('%Y-%m-%d %H:%M'), format_time(now)
+        assert_equal now.strftime('%H:%M'), format_time(now, false)
       end
     end
   end
 
   def test_time_format_default
     set_language_if_valid 'en'
-    now = Time.parse('2011-02-20 15:45:22')
+    now = Time.zone.parse('2011-02-20 15:45:22')
     with_settings :time_format => '' do
       with_settings :date_format => '' do
-        assert_equal '02/20/2011 03:45 PM', format_time(now)
-        assert_equal '03:45 PM', format_time(now, false)
+        assert_equal now.strftime('%m/%d/%Y %I:%M %p'), format_time(now)
+        assert_equal now.strftime('%I:%M %p'), format_time(now, false)
       end
       with_settings :date_format => '%Y-%m-%d' do
-        assert_equal '2011-02-20 03:45 PM', format_time(now)
-        assert_equal '03:45 PM', format_time(now, false)
+        assert_equal now.strftime('%Y-%m-%d %I:%M %p'), format_time(now)
+        assert_equal now.strftime('%I:%M %p'), format_time(now, false)
       end
     end
   end
 
   def test_utc_time_format
     set_language_if_valid 'en'
-    now = Time.now
+    now = Time.current
     with_settings :date_format => '%d %m %Y', :time_format => '%H %M' do
-      assert_equal now.localtime.strftime('%d %m %Y %H %M'), format_time(now.utc), "User time zone was #{User.current.time_zone}"
-      assert_equal now.localtime.strftime('%H %M'), format_time(now.utc, false)
+      assert_equal now.strftime('%d %m %Y %H %M'), format_time(now.utc), "User time zone was #{User.current.time_zone}"
+      assert_equal now.strftime('%H %M'), format_time(now.utc, false)
     end
   end
 
diff --git a/test/unit/mail_handler_test.rb b/test/unit/mail_handler_test.rb
index 1672edccb..cd19e846a 100644
--- a/test/unit/mail_handler_test.rb
+++ b/test/unit/mail_handler_test.rb
@@ -289,7 +289,7 @@ class MailHandlerTest < ActiveSupport::TestCase
     with_settings :default_issue_start_date_to_creation_date => '1' do
       issue = submit_email('ticket_with_cc.eml', :issue => {:project => 'ecookbook'})
       assert issue.is_a?(Issue)
-      assert_equal Date.today, issue.start_date
+      assert_equal Date.current, issue.start_date
     end
   end
 
diff --git a/test/unit/mailer_test.rb b/test/unit/mailer_test.rb
index b676a4503..641822dd2 100644
--- a/test/unit/mailer_test.rb
+++ b/test/unit/mailer_test.rb
@@ -685,7 +685,6 @@ class MailerTest < ActiveSupport::TestCase
   end
 
   def test_reminders
-    users(:users_003).pref.update_attribute :time_zone, 'UTC' # dlopper
     days = 42
     Mailer.reminders(:days => days)
     assert_equal 1, ActionMailer::Base.deliveries.size
@@ -709,7 +708,6 @@ class MailerTest < ActiveSupport::TestCase
     with_settings :default_language => 'fr' do
       user = User.find(3)
       user.update_attribute :language, ''
-      user.pref.update_attribute :time_zone, 'UTC'
       Mailer.reminders(:days => 42)
       assert_equal 1, ActionMailer::Base.deliveries.size
       mail = last_email
@@ -736,7 +734,6 @@ class MailerTest < ActiveSupport::TestCase
   end
 
   def test_reminders_for_users
-    users(:users_003).pref.update_attribute :time_zone, 'UTC' # dlopper
     Mailer.reminders(:days => 42, :users => ['5'])
     assert_equal 0, ActionMailer::Base.deliveries.size # No mail for dlopper
     Mailer.reminders(:days => 42, :users => ['3'])
@@ -752,7 +749,6 @@ class MailerTest < ActiveSupport::TestCase
       Member.create!(:project_id => 1, :principal => group, :role_ids => [1])
       [users(:users_002), users(:users_003)].each do |user| # jsmith, dlopper
         group.users << user
-        user.pref.update_attribute :time_zone, 'UTC'
       end
 
       Issue.update_all(:assigned_to_id => nil)
@@ -810,7 +806,6 @@ class MailerTest < ActiveSupport::TestCase
 
   def test_reminders_should_sort_issues_by_due_date
     user = User.find(2)
-    user.pref.update_attribute :time_zone, 'UTC'
     Issue.generate!(:assigned_to => user, :due_date => 2.days.from_now, :subject => 'quux')
     Issue.generate!(:assigned_to => user, :due_date => 0.days.from_now, :subject => 'baz')
     Issue.generate!(:assigned_to => user, :due_date => 1.days.from_now, :subject => 'qux')
diff --git a/test/unit/query_test.rb b/test/unit/query_test.rb
index f0f27b9c0..be8324770 100644
--- a/test/unit/query_test.rb
+++ b/test/unit/query_test.rb
@@ -523,6 +523,14 @@ class QueryTest < ActiveSupport::TestCase
     assert !query.valid?
   end
 
+  def test_date_filter_should_not_accept_invalid_timestamp_values
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('created_on', '=', ['2011-01-30T24:00:01'])
+
+    assert query.has_filter?('created_on')
+    assert !query.valid?
+  end
+
   def test_relative_date_filter_should_not_accept_non_integer_values
     query = IssueQuery.new(:name => '_')
     query.add_filter('created_on', '>t-', ['a'])
@@ -534,54 +542,112 @@ class QueryTest < ActiveSupport::TestCase
   def test_operator_date_equals
     query = IssueQuery.new(:name => '_')
     query.add_filter('due_date', '=', ['2011-07-10'])
-    assert_match /issues\.due_date > '#{quoted_date "2011-07-09"} 23:59:59(\.\d+)?' AND issues\.due_date <= '#{quoted_date "2011-07-10"} 23:59:59(\.\d+)?/,
+    assert_match /issues\.due_date >= '#{quoted_date '2011-07-10'}' AND issues\.due_date <= '#{quoted_date '2011-07-10'}'/,
                  query.statement
     find_issues_with_query(query)
+
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('updated_on', '=', ['2011-07-10'])
+    assert_match /issues\.updated_on > '#{quoted_date Time.zone.parse('2011-07-09').end_of_day}' AND issues\.updated_on <= '#{quoted_date Time.zone.parse('2011-07-10').end_of_day}'/,
+                 query.statement
+    find_issues_with_query(query)
+  end
+
+  def test_operator_date_equals_with_timestamp
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('due_date', '=', ['2011-07-10T19:13:52'])
+    assert_match /issues\.due_date >= '#{quoted_date '2011-07-10T19:13:52'}' AND issues\.due_date <= '#{quoted_date '2011-07-10T19:13:52'}'/, query.statement
+    find_issues_with_query(query)
+
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('updated_on', '=', ['2011-07-10T19:13:52'])
+    assert_match /issues\.updated_on > '#{quoted_date '2011-07-10T19:13:51'.to_time}' AND issues\.updated_on <= '#{quoted_date '2011-07-10T19:13:52'.to_time}'/, query.statement
+    find_issues_with_query(query)
   end
 
   def test_operator_date_lesser_than
     query = IssueQuery.new(:name => '_')
     query.add_filter('due_date', '<=', ['2011-07-10'])
-    assert_match /issues\.due_date <= '#{quoted_date "2011-07-10"} 23:59:59(\.\d+)?/, query.statement
+    assert_match /issues\.due_date <= '#{quoted_date '2011-07-10'}'/, query.statement
+    find_issues_with_query(query)
+
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('updated_on', '<=', ['2011-07-10'])
+    assert_match /issues\.updated_on <= '#{quoted_date Time.zone.parse('2011-07-10').end_of_day}'/, query.statement
     find_issues_with_query(query)
   end
 
   def test_operator_date_lesser_than_with_timestamp
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('due_date', '<=', ['2011-07-10T19:13:52'])
+    assert_match /issues\.due_date <= '#{quoted_date '2011-07-10T19:13:52'}/, query.statement
+    find_issues_with_query(query)
+
     query = IssueQuery.new(:name => '_')
     query.add_filter('updated_on', '<=', ['2011-07-10T19:13:52'])
-    assert_match /issues\.updated_on <= '#{quoted_date "2011-07-10"} 19:13:52/, query.statement
+    assert_match /issues\.updated_on <= '#{quoted_date '2011-07-10T19:13:52'.to_time}/, query.statement
     find_issues_with_query(query)
   end
 
   def test_operator_date_greater_than
     query = IssueQuery.new(:name => '_')
     query.add_filter('due_date', '>=', ['2011-07-10'])
-    assert_match /issues\.due_date > '#{quoted_date "2011-07-09"} 23:59:59(\.\d+)?'/, query.statement
+    assert_match /issues\.due_date >= '#{quoted_date '2011-07-10'}'/, query.statement
+    find_issues_with_query(query)
+
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('updated_on', '>=', ['2011-07-10'])
+    assert_match /issues\.updated_on > '#{quoted_date Time.zone.parse('2011-07-09').end_of_day}'/, query.statement
     find_issues_with_query(query)
   end
 
   def test_operator_date_greater_than_with_timestamp
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('due_date', '>=', ['2011-07-10T19:13:52'])
+    assert_match /issues\.due_date >= '#{quoted_date '2011-07-10T19:13:52'}'/, query.statement
+    find_issues_with_query(query)
+
     query = IssueQuery.new(:name => '_')
     query.add_filter('updated_on', '>=', ['2011-07-10T19:13:52'])
-    assert_match /issues\.updated_on > '#{quoted_date "2011-07-10"} 19:13:51(\.0+)?'/, query.statement
+    assert_match /issues\.updated_on > '#{quoted_date '2011-07-10T19:13:51'.to_time}'/, query.statement
     find_issues_with_query(query)
   end
 
   def test_operator_date_between
     query = IssueQuery.new(:name => '_')
     query.add_filter('due_date', '><', ['2011-06-23', '2011-07-10'])
-    assert_match /issues\.due_date > '#{quoted_date "2011-06-22"} 23:59:59(\.\d+)?' AND issues\.due_date <= '#{quoted_date "2011-07-10"} 23:59:59(\.\d+)?'/,
+    assert_match /issues\.due_date >= '#{quoted_date '2011-06-23'}' AND issues\.due_date <= '#{quoted_date '2011-07-10'}'/,
+                 query.statement
+    find_issues_with_query(query)
+
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('updated_on', '><', ['2011-06-23', '2011-07-10'])
+    assert_match /issues\.updated_on > '#{quoted_date Time.zone.parse('2011-06-22').end_of_day}' AND issues\.updated_on <= '#{quoted_date Time.zone.parse('2011-07-10').end_of_day}'/,
+                 query.statement
+    find_issues_with_query(query)
+  end
+
+  def test_operator_date_between_with_timestamp
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('due_date', '><', ['2011-06-23T19:13:52', '2011-07-10T19:13:52'])
+    assert_match /issues\.due_date >= '#{quoted_date '2011-06-23T19:13:52'}' AND issues\.due_date <= '#{quoted_date '2011-07-10T19:13:52'}'/,
+                 query.statement
+    find_issues_with_query(query)
+
+    query = IssueQuery.new(:name => '_')
+    query.add_filter('updated_on', '><', ['2011-06-23T19:13:52', '2011-07-10T19:13:52'])
+    assert_match /issues\.updated_on > '#{quoted_date '2011-06-23T19:13:51'.to_time}' AND issues\.updated_on <= '#{quoted_date '2011-07-10T19:13:52'.to_time}'/,
                  query.statement
     find_issues_with_query(query)
   end
 
   def test_operator_in_more_than
-    Issue.find(7).update_attribute(:due_date, (Date.today + 15))
+    Issue.find(7).update_attribute(:due_date, (Date.current + 15))
     query = IssueQuery.new(:project => Project.find(1), :name => '_')
     query.add_filter('due_date', '>t+', ['15'])
     issues = find_issues_with_query(query)
     assert !issues.empty?
-    issues.each {|issue| assert(issue.due_date >= (Date.today + 15))}
+    issues.each {|issue| assert(issue.due_date >= (Date.current + 15))}
   end
 
   def test_operator_in_less_than
@@ -589,7 +655,7 @@ class QueryTest < ActiveSupport::TestCase
     query.add_filter('due_date', '<t+', ['15'])
     issues = find_issues_with_query(query)
     assert !issues.empty?
-    issues.each {|issue| assert(issue.due_date <= (Date.today + 15))}
+    issues.each {|issue| assert(issue.due_date <= (Date.current + 15))}
   end
 
   def test_operator_in_the_next_days
@@ -597,53 +663,53 @@ class QueryTest < ActiveSupport::TestCase
     query.add_filter('due_date', '><t+', ['15'])
     issues = find_issues_with_query(query)
     assert !issues.empty?
-    issues.each {|issue| assert(issue.due_date >= Date.today && issue.due_date <= (Date.today + 15))}
+    issues.each {|issue| assert(issue.due_date >= Date.current && issue.due_date <= (Date.current + 15))}
   end
 
   def test_operator_less_than_ago
-    Issue.find(7).update_attribute(:due_date, (Date.today - 3))
+    Issue.find(7).update_attribute(:due_date, (Date.current - 3))
     query = IssueQuery.new(:project => Project.find(1), :name => '_')
     query.add_filter('due_date', '>t-', ['3'])
     issues = find_issues_with_query(query)
     assert !issues.empty?
-    issues.each {|issue| assert(issue.due_date >= (Date.today - 3))}
+    issues.each {|issue| assert(issue.due_date >= (Date.current - 3))}
   end
 
   def test_operator_in_the_past_days
-    Issue.find(7).update_attribute(:due_date, (Date.today - 3))
+    Issue.find(7).update_attribute(:due_date, (Date.current - 3))
     query = IssueQuery.new(:project => Project.find(1), :name => '_')
     query.add_filter('due_date', '><t-', ['3'])
     issues = find_issues_with_query(query)
     assert !issues.empty?
-    issues.each {|issue| assert(issue.due_date >= (Date.today - 3) && issue.due_date <= Date.today)}
+    issues.each {|issue| assert(issue.due_date >= (Date.current - 3) && issue.due_date <= Date.current)}
   end
 
   def test_operator_more_than_ago
-    Issue.find(7).update_attribute(:due_date, (Date.today - 10))
+    Issue.find(7).update_attribute(:due_date, (Date.current - 10))
     query = IssueQuery.new(:project => Project.find(1), :name => '_')
     query.add_filter('due_date', '<t-', ['10'])
     assert query.statement.include?("#{Issue.table_name}.due_date <=")
     issues = find_issues_with_query(query)
     assert !issues.empty?
-    issues.each {|issue| assert(issue.due_date <= (Date.today - 10))}
+    issues.each {|issue| assert(issue.due_date <= (Date.current - 10))}
   end
 
   def test_operator_in
-    Issue.find(7).update_attribute(:due_date, (Date.today + 2))
+    Issue.find(7).update_attribute(:due_date, (Date.current + 2))
     query = IssueQuery.new(:project => Project.find(1), :name => '_')
     query.add_filter('due_date', 't+', ['2'])
     issues = find_issues_with_query(query)
     assert !issues.empty?
-    issues.each {|issue| assert_equal((Date.today + 2), issue.due_date)}
+    issues.each {|issue| assert_equal((Date.current + 2), issue.due_date)}
   end
 
   def test_operator_ago
-    Issue.find(7).update_attribute(:due_date, (Date.today - 3))
+    Issue.find(7).update_attribute(:due_date, (Date.current - 3))
     query = IssueQuery.new(:project => Project.find(1), :name => '_')
     query.add_filter('due_date', 't-', ['3'])
     issues = find_issues_with_query(query)
     assert !issues.empty?
-    issues.each {|issue| assert_equal((Date.today - 3), issue.due_date)}
+    issues.each {|issue| assert_equal((Date.current - 3), issue.due_date)}
   end
 
   def test_operator_today
@@ -651,7 +717,7 @@ class QueryTest < ActiveSupport::TestCase
     query.add_filter('due_date', 't', [''])
     issues = find_issues_with_query(query)
     assert !issues.empty?
-    issues.each {|issue| assert_equal Date.today, issue.due_date}
+    issues.each {|issue| assert_equal Date.current, issue.due_date}
   end
 
   def test_operator_tomorrow
@@ -714,62 +780,64 @@ class QueryTest < ActiveSupport::TestCase
   end
 
   def test_range_for_this_week_with_week_starting_on_monday
-    I18n.locale = :fr
-    assert_equal '1', I18n.t(:general_first_day_of_week)
-
-    Date.stubs(:today).returns(Date.parse('2011-04-29'))
-
-    query = IssueQuery.new(:project => Project.find(1), :name => '_')
-    query.add_filter('due_date', 'w', [''])
-    assert_match /issues\.due_date > '#{quoted_date "2011-04-24"} 23:59:59(\.\d+)?' AND issues\.due_date <= '#{quoted_date "2011-05-01"} 23:59:59(\.\d+)?/,
-                 query.statement
-    I18n.locale = :en
+    with_locale :fr do
+      assert_equal '1', I18n.t(:general_first_day_of_week)
+
+      travel_to Date.parse('2011-04-29') do
+        query = IssueQuery.new(:project => Project.find(1), :name => '_')
+        query.add_filter('due_date', 'w', [''])
+        assert_match /issues\.due_date >= '#{quoted_date '2011-04-25'}' AND issues\.due_date <= '#{quoted_date '2011-05-01'}'/,
+                     query.statement
+      end
+    end
   end
 
   def test_range_for_this_week_with_week_starting_on_sunday
-    I18n.locale = :en
-    assert_equal '7', I18n.t(:general_first_day_of_week)
-
-    Date.stubs(:today).returns(Date.parse('2011-04-29'))
-
-    query = IssueQuery.new(:project => Project.find(1), :name => '_')
-    query.add_filter('due_date', 'w', [''])
-    assert_match /issues\.due_date > '#{quoted_date "2011-04-23"} 23:59:59(\.\d+)?' AND issues\.due_date <= '#{quoted_date "2011-04-30"} 23:59:59(\.\d+)?/,
-                 query.statement
+    with_locale :en do
+      assert_equal '7', I18n.t(:general_first_day_of_week)
+
+      travel_to Date.parse('2011-04-29') do
+        query = IssueQuery.new(:project => Project.find(1), :name => '_')
+        query.add_filter('due_date', 'w', [''])
+        assert_match /issues\.due_date >= '#{quoted_date '2011-04-24'}' AND issues\.due_date <= '#{quoted_date '2011-04-30'}'/,
+                     query.statement
+      end
+    end
   end
 
   def test_range_for_next_week_with_week_starting_on_monday
-    I18n.locale = :fr
-    assert_equal '1', I18n.t(:general_first_day_of_week)
-
-    Date.stubs(:today).returns(Date.parse('2011-04-29')) # Friday
-
-    query = IssueQuery.new(:project => Project.find(1), :name => '_')
-    query.add_filter('due_date', 'nw', [''])
-    assert_match /issues\.due_date > '#{quoted_date "2011-05-01"} 23:59:59(\.\d+)?' AND issues\.due_date <= '#{quoted_date "2011-05-08"} 23:59:59(\.\d+)?/,
-                 query.statement
-    I18n.locale = :en
+    with_locale :fr do
+      assert_equal '1', I18n.t(:general_first_day_of_week)
+
+      travel_to Date.parse('2011-04-29') do
+        query = IssueQuery.new(:project => Project.find(1), :name => '_')
+        query.add_filter('due_date', 'nw', [''])
+        assert_match /issues\.due_date >= '#{quoted_date '2011-05-02'}' AND issues\.due_date <= '#{quoted_date '2011-05-08'}'/,
+                     query.statement
+      end
+    end
   end
 
   def test_range_for_next_week_with_week_starting_on_sunday
-    I18n.locale = :en
-    assert_equal '7', I18n.t(:general_first_day_of_week)
-
-    Date.stubs(:today).returns(Date.parse('2011-04-29')) # Friday
-
-    query = IssueQuery.new(:project => Project.find(1), :name => '_')
-    query.add_filter('due_date', 'nw', [''])
-    assert_match /issues\.due_date > '#{quoted_date "2011-04-30"} 23:59:59(\.\d+)?' AND issues\.due_date <= '#{quoted_date "2011-05-07"} 23:59:59(\.\d+)?/,
-                 query.statement
+    with_locale :en do
+      assert_equal '7', I18n.t(:general_first_day_of_week)
+
+      travel_to Date.parse('2011-04-29') do
+        query = IssueQuery.new(:project => Project.find(1), :name => '_')
+        query.add_filter('due_date', 'nw', [''])
+        assert_match /issues\.due_date >= '#{quoted_date '2011-05-01'}' AND issues\.due_date <= '#{quoted_date '2011-05-07'}'/,
+                     query.statement
+      end
+    end
   end
 
   def test_range_for_next_month
-    Date.stubs(:today).returns(Date.parse('2011-04-29')) # Friday
-
-    query = IssueQuery.new(:project => Project.find(1), :name => '_')
-    query.add_filter('due_date', 'nm', [''])
-    assert_match /issues\.due_date > '#{quoted_date "2011-04-30"} 23:59:59(\.\d+)?' AND issues\.due_date <= '#{quoted_date "2011-05-31"} 23:59:59(\.\d+)?/,
-                 query.statement
+    travel_to Date.parse('2011-04-29') do
+      query = IssueQuery.new(:project => Project.find(1), :name => '_')
+      query.add_filter('due_date', 'nm', [''])
+      assert_match /issues\.due_date >= '#{quoted_date '2011-05-01'}' AND issues\.due_date <= '#{quoted_date '2011-05-31'}'/,
+                   query.statement
+    end
   end
 
   def test_filter_assigned_to_me
diff --git a/test/unit/user_test.rb b/test/unit/user_test.rb
index 56e4c5ecf..57039397e 100644
--- a/test/unit/user_test.rb
+++ b/test/unit/user_test.rb
@@ -578,19 +578,16 @@ class UserTest < ActiveSupport::TestCase
 
   def test_today_should_return_the_day_according_to_user_time_zone
     preference = User.find(1).pref
-    date = Date.new(2012, 05, 15)
-    time = Time.gm(2012, 05, 15, 23, 30).utc # 2012-05-15 23:30 UTC
-    Date.stubs(:today).returns(date)
-    Time.stubs(:now).returns(time)
-
-    preference.update_attribute :time_zone, 'Baku' # UTC+4
-    assert_equal '2012-05-16', User.find(1).today.to_s
+    travel_to Time.gm(2012, 05, 15, 23, 30).utc do
+      preference.update_attribute :time_zone, 'Baku' # UTC+4
+      assert_equal '2012-05-16', User.find(1).today.to_s
 
-    preference.update_attribute :time_zone, 'La Paz' # UTC-4
-    assert_equal '2012-05-15', User.find(1).today.to_s
+      preference.update_attribute :time_zone, 'La Paz' # UTC-4
+      assert_equal '2012-05-15', User.find(1).today.to_s
 
-    preference.update_attribute :time_zone, ''
-    assert_equal '2012-05-15', User.find(1).today.to_s
+      preference.update_attribute :time_zone, ''
+      assert_equal Date.current.to_s, User.find(1).today.to_s
+    end
   end
 
   def test_time_to_date_should_return_the_date_according_to_user_time_zone
@@ -604,7 +601,8 @@ class UserTest < ActiveSupport::TestCase
     assert_equal '2012-05-15', User.find(1).time_to_date(time).to_s
 
     preference.update_attribute :time_zone, ''
-    assert_equal time.localtime.to_date.to_s, User.find(1).time_to_date(time).to_s
+    user = User.find(1)
+    assert_equal time.in_time_zone(user.time_zone).to_date.to_s, user.time_to_date(time).to_s
   end
 
   def test_convert_time_to_user_timezone_should_return_the_time_according_to_user_time_zone
@@ -619,8 +617,9 @@ class UserTest < ActiveSupport::TestCase
     assert_equal '2012-05-15 19:30:00 -0400', User.find(1).convert_time_to_user_timezone(time).to_s
 
     preference.update_attribute :time_zone, ''
-    assert_equal time.localtime.to_s, User.find(1).convert_time_to_user_timezone(time).to_s
-    assert_equal time_not_utc, User.find(1).convert_time_to_user_timezone(time_not_utc)
+    user = User.find(1)
+    assert_equal time.in_time_zone(user.time_zone).to_s, user.convert_time_to_user_timezone(time).to_s
+    assert_equal time_not_utc, user.convert_time_to_user_timezone(time_not_utc)
   end
 
   def test_fields_for_order_statement_should_return_fields_according_user_format_setting
diff --git a/test/unit/version_test.rb b/test/unit/version_test.rb
index af752f0a1..ca7bc2b37 100644
--- a/test/unit/version_test.rb
+++ b/test/unit/version_test.rb
@@ -158,7 +158,7 @@ class VersionTest < ActiveSupport::TestCase
   end
 
   def test_completed_should_be_false_when_due_today
-    version = Version.create!(:project_id => 1, :effective_date => Date.today, :name => 'Due today')
+    version = Version.create!(:project_id => 1, :effective_date => Date.current, :name => 'Due today')
     assert_equal false, version.completed?
   end