diff --git a/test/unit/activity_stream_test.rb b/test/unit/activity_stream_test.rb
index 74b18c087..13d2356f2 100644
--- a/test/unit/activity_stream_test.rb
+++ b/test/unit/activity_stream_test.rb
@@ -4,7 +4,6 @@ require 'test_helper'
 class ActivityStreamTest < ActiveSupport::TestCase
   admin_user = nil
   current_user = nil
-  activity_record_delay = nil
   test 'aaa - setup' do
     role  = Role.lookup(name: 'Admin')
     group = Group.lookup(name: 'Users')
@@ -21,12 +20,6 @@ class ActivityStreamTest < ActiveSupport::TestCase
       created_by_id: 1
     )
     current_user = User.lookup(email: 'nicole.braun@zammad.org')
-
-    activity_record_delay = if ENV['ZAMMAD_ACTIVITY_RECORD_DELAY']
-                              ENV['ZAMMAD_ACTIVITY_RECORD_DELAY'].to_i.seconds
-                            else
-                              90.seconds
-                            end
   end
 
   test 'ticket+user' do
@@ -101,7 +94,7 @@ class ActivityStreamTest < ActiveSupport::TestCase
       test[:check][2][:o_id]          = ticket.id
       test[:check][2][:created_at]    = ticket.created_at
       test[:check][2][:created_by_id] = current_user.id
-      sleep 2
+      travel 2.seconds
 
       test[:create][:article][:ticket_id] = ticket.id
       article = Ticket::Article.create(test[:create][:article])
@@ -129,7 +122,7 @@ class ActivityStreamTest < ActiveSupport::TestCase
         article.update_attributes(test[:update][:article])
       end
 
-      sleep activity_record_delay + 1
+      travel 1.second
       if test[:update][:ticket]
         ticket.update_attributes(test[:update][:ticket])
       end
@@ -196,7 +189,7 @@ class ActivityStreamTest < ActiveSupport::TestCase
       test[:check][0][:o_id]          = organization.id
       test[:check][0][:created_at]    = organization.created_at
       test[:check][0][:created_by_id] = current_user.id
-      sleep 2
+      travel 2.seconds
 
       assert_equal(organization.class.to_s, 'Organization')
 
@@ -205,7 +198,7 @@ class ActivityStreamTest < ActiveSupport::TestCase
         test[:check][1][:o_id]          = organization.id
         test[:check][1][:updated_at]    = organization.updated_at
         test[:check][1][:created_by_id] = current_user.id
-        sleep activity_record_delay - 1
+        travel 1.second
       end
 
       if test[:update2][:organization]
@@ -353,7 +346,7 @@ class ActivityStreamTest < ActiveSupport::TestCase
       end
 
       # to verify update which need to be logged
-      sleep activity_record_delay + 1
+      travel 1.second
 
       if test[:update2][:user]
         user.update_attributes(test[:update2][:user])
diff --git a/test/unit/assets_test.rb b/test/unit/assets_test.rb
index 79bd832e6..5241a1b9e 100644
--- a/test/unit/assets_test.rb
+++ b/test/unit/assets_test.rb
@@ -84,7 +84,7 @@ class AssetsTest < ActiveSupport::TestCase
     assert( diff(attributes, assets[:User][user3.id]), 'check assets' )
 
     # touch org, check if user1 has changed
-    sleep 2
+    travel 2.seconds
     org2 = Organization.find(org.id)
     org2.note = "some note...#{rand(9_999_999_999_999)}"
     org2.save
@@ -232,7 +232,7 @@ class AssetsTest < ActiveSupport::TestCase
     assert_nil( assets[:User][user3.id], 'check assets' )
 
     # touch user 2, check if org has changed
-    sleep 2
+    travel 2.seconds
     user_new_2 = User.find(user2.id)
     user_new_2.lastname = 'assets2'
     user_new_2.save
diff --git a/test/unit/calendar_test.rb b/test/unit/calendar_test.rb
index 485a69044..375df4123 100644
--- a/test/unit/calendar_test.rb
+++ b/test/unit/calendar_test.rb
@@ -19,7 +19,7 @@ class CalendarTest < ActiveSupport::TestCase
       updated_by_id: 1,
       created_by_id: 1,
     )
-    sleep 1
+    travel 1.second
     calendar2 = Calendar.create_or_update(
       name: 'US 2',
       timezone: 'America/Los_Angeles',
diff --git a/test/unit/chat_test.rb b/test/unit/chat_test.rb
index b94b16477..4e0d79ba5 100644
--- a/test/unit/chat_test.rb
+++ b/test/unit/chat_test.rb
@@ -208,19 +208,19 @@ class ChatTest < ActiveSupport::TestCase
       content: 'message 1',
       created_by_id: agent1.id,
     )
-    sleep 1
+    travel 1.second
     Chat::Message.create(
       chat_session_id: chat_session6.id,
       content: 'message 2',
       created_by_id: agent1.id,
     )
-    sleep 1
+    travel 1.second
     Chat::Message.create(
       chat_session_id: chat_session6.id,
       content: 'message 3',
       created_by_id: agent1.id,
     )
-    sleep 1
+    travel 1.second
     Chat::Message.create(
       chat_session_id: chat_session6.id,
       content: 'message 4',
diff --git a/test/unit/email_process_bounce_test.rb b/test/unit/email_process_bounce_test.rb
index 29fb303f3..b4cedd7ac 100644
--- a/test/unit/email_process_bounce_test.rb
+++ b/test/unit/email_process_bounce_test.rb
@@ -27,7 +27,7 @@ class EmailProcessBounceTest < ActiveSupport::TestCase
       updated_by_id: 1,
       created_by_id: 1,
     )
-    sleep 1
+    travel 1.second
     email_raw_string = IO.binread('test/fixtures/mail33-undelivered-mail-returned-to-sender.box')
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string)
     assert_equal(ticket.id, ticket_p.id)
diff --git a/test/unit/email_process_follow_up_test.rb b/test/unit/email_process_follow_up_test.rb
index c1ecd19d1..7c512f65f 100644
--- a/test/unit/email_process_follow_up_test.rb
+++ b/test/unit/email_process_follow_up_test.rb
@@ -84,45 +84,45 @@ no reference "
     setting_orig = Setting.get('postmaster_follow_up_search_in')
     Setting.set('postmaster_follow_up_search_in', %w(body attachment references))
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_subject)
     assert_equal(ticket.id, ticket_p.id)
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_body)
     assert_equal(ticket.id, ticket_p.id)
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_attachment)
     assert_equal(ticket.id, ticket_p.id)
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_references1)
     assert_equal(ticket.id, ticket_p.id)
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_references2)
     assert_equal(ticket.id, ticket_p.id)
 
     Setting.set('postmaster_follow_up_search_in', setting_orig)
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_subject)
     assert_equal(ticket.id, ticket_p.id)
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_body)
     assert_not_equal(ticket.id, ticket_p.id)
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_attachment)
     assert_not_equal(ticket.id, ticket_p.id)
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_references1)
     assert_not_equal(ticket.id, ticket_p.id)
 
-    sleep 1
+    travel 1.second
     ticket_p, article_p, user_p = Channel::EmailParser.new.process({}, email_raw_string_references2)
     assert_not_equal(ticket.id, ticket_p.id)
   end
@@ -141,7 +141,7 @@ test 123
 "
     ticket_p1, article_p1, user_p1 = Channel::EmailParser.new.process({}, data1)
 
-    sleep 1
+    travel 1.second
 
     data1 = "From: me@example.com
 To: z@example.com
@@ -193,7 +193,7 @@ test 123
       updated_by_id: 1,
       created_by_id: 1,
     )
-    sleep 1
+    travel 1.second
 
     # auto response without T# in subject, find follow up by references header
     email_raw_string = "From: bob@example.com
@@ -237,7 +237,7 @@ Some Text"
       updated_by_id: 1,
       created_by_id: 1,
     )
-    sleep 1
+    travel 1.second
 
     system_id           = Setting.get('system_id')
     ticket_hook         = Setting.get('ticket_hook')
diff --git a/test/unit/email_process_out_of_office_test.rb b/test/unit/email_process_out_of_office_test.rb
index 0b5ee0633..0c8135ec0 100644
--- a/test/unit/email_process_out_of_office_test.rb
+++ b/test/unit/email_process_out_of_office_test.rb
@@ -27,7 +27,7 @@ class EmailProcessOutOfOfficeTest < ActiveSupport::TestCase
       updated_by_id: 1,
       created_by_id: 1,
     )
-    sleep 1
+    travel 1.second
 
     # exchange out of office example #1
     email_raw_string = "From: me@example.com
@@ -113,7 +113,7 @@ Some Text"
       updated_by_id: 1,
       created_by_id: 1,
     )
-    sleep 1
+    travel 1.second
 
     # exchange out of office example #1
     email_raw_string = "From: me@example.com
@@ -191,7 +191,7 @@ Some Text"
       updated_by_id: 1,
       created_by_id: 1,
     )
-    sleep 1
+    travel 1.second
 
     # exchange out of office example #1
     email_raw_string = "From: me@example.com
@@ -264,7 +264,7 @@ Some Text"
       updated_by_id: 1,
       created_by_id: 1,
     )
-    sleep 1
+    travel 1.second
 
     # gmail out of office example #1
     email_raw_string = "From: me@example.com
diff --git a/test/unit/karma_test.rb b/test/unit/karma_test.rb
index c26498cee..9d4a52c19 100644
--- a/test/unit/karma_test.rb
+++ b/test/unit/karma_test.rb
@@ -329,7 +329,7 @@ class KarmaTest < ActiveSupport::TestCase
       item: 'Tag1',
       created_by_id: agent1.id,
     )
-    #sleep 5
+    #travel 5.seconds
     Tag.tag_add(
       object: 'Ticket',
       o_id: ticket1.id,
diff --git a/test/unit/organization_ref_object_touch_test.rb b/test/unit/organization_ref_object_touch_test.rb
index c8821bb10..b34879385 100644
--- a/test/unit/organization_ref_object_touch_test.rb
+++ b/test/unit/organization_ref_object_touch_test.rb
@@ -81,7 +81,7 @@ class OrganizationRefObjectTouchTest < ActiveSupport::TestCase
     assert_equal(ticket.customer.id, customer1.id)
     assert_equal(ticket.organization.id, organization1.id)
 
-    sleep 4
+    travel 4.seconds
 
     organization1.name = 'Ref Object Update Org 1/1'
     organization1.save
@@ -101,7 +101,7 @@ class OrganizationRefObjectTouchTest < ActiveSupport::TestCase
       assert(false, 'customer1.updated_at has not been updated')
     end
 
-    sleep 4
+    travel 4.seconds
 
     customer2.organization_id = organization1.id
     customer2.save
diff --git a/test/unit/recent_view_test.rb b/test/unit/recent_view_test.rb
index fe3b5345a..5a1a7d210 100644
--- a/test/unit/recent_view_test.rb
+++ b/test/unit/recent_view_test.rb
@@ -29,11 +29,11 @@ class RecentViewTest < ActiveSupport::TestCase
     RecentView.user_log_destroy(user1)
 
     RecentView.log(ticket1.class.to_s, ticket1.id, user1)
-    sleep 1
+    travel 1.second
     RecentView.log(ticket2.class.to_s, ticket2.id, user1)
-    sleep 1
+    travel 1.second
     RecentView.log(ticket1.class.to_s, ticket1.id, user1)
-    sleep 1
+    travel 1.second
     RecentView.log(ticket1.class.to_s, ticket1.id, user1)
 
     list = RecentView.list(user1)
diff --git a/test/unit/session_basic_test.rb b/test/unit/session_basic_test.rb
index 440afcae6..fc44cd5db 100644
--- a/test/unit/session_basic_test.rb
+++ b/test/unit/session_basic_test.rb
@@ -19,7 +19,7 @@ class SessionBasicTest < ActiveSupport::TestCase
     assert_equal(false, result, 'check 1 - expired')
 
     # should be expired
-    sleep 2
+    travel 2.seconds
     result = Sessions::CacheIn.expired('last_run_test')
     assert_equal(true, result, 'check 1 - expired')
 
@@ -32,7 +32,7 @@ class SessionBasicTest < ActiveSupport::TestCase
     assert_equal(false, result, 'check 1 - expired')
 
     # ignore expired
-    sleep 2
+    travel 2.seconds
     result = Sessions::CacheIn.get('last_run_test', ignore_expire: true)
     assert_equal(true, result, 'check 1 - ignore_expire')
 
@@ -124,14 +124,14 @@ class SessionBasicTest < ActiveSupport::TestCase
     # next check should be empty
     result1 = collection_client1.push
     assert(!result1, 'check collections - recall')
-    sleep 1
+    travel 1.second
     result2 = collection_client2.push
     assert(!result2, 'check collections - recall')
 
     # change collection
     group = Group.first
     group.touch
-    sleep 4
+    travel 4.seconds
 
     # get whole collections
     result1 = collection_client1.push
@@ -149,7 +149,7 @@ class SessionBasicTest < ActiveSupport::TestCase
 
     # change collection
     group = Group.create(name: "SomeGroup::#{rand(999_999)}", active: true)
-    sleep 4
+    travel 4.seconds
 
     # get whole collections
     result1 = collection_client1.push
@@ -159,7 +159,7 @@ class SessionBasicTest < ActiveSupport::TestCase
     assert_equal(result1, result2, 'check collections')
 
     # check again after create
-    sleep 4
+    travel 4.seconds
     result1 = collection_client1.push
     assert(!result1, 'check collections - after create - recall')
     result2 = collection_client2.push
@@ -168,7 +168,7 @@ class SessionBasicTest < ActiveSupport::TestCase
 
     # change collection
     group.destroy
-    sleep 4
+    travel 4.seconds
 
     # get whole collections
     result1 = collection_client1.push
@@ -178,7 +178,7 @@ class SessionBasicTest < ActiveSupport::TestCase
     assert_equal(result1, result2, 'check collections')
 
     # check again after destroy
-    sleep 4
+    travel 4.seconds
     result1 = collection_client1.push
     assert(!result1, 'check collections - after destroy - recall')
     result2 = collection_client2.push
@@ -211,21 +211,21 @@ class SessionBasicTest < ActiveSupport::TestCase
     # get as stream
     result1 = as_client1.push
     assert(result1, 'check as agent1')
-    sleep 1
+    travel 1.second
 
     # next check should be empty
     result1 = as_client1.push
     assert(!result1, 'check as agent1 - recall')
 
     # next check should be empty
-    sleep 4
+    travel 4.seconds
     result1 = as_client1.push
     assert(!result1, 'check as agent1 - recall 2')
 
     agent1.update_attribute(:email, 'activity-stream-agent11@example.com')
     ticket = Ticket.create(title: '12323', group_id: 1, priority_id: 1, state_id: 1, customer_id: 1)
 
-    sleep 4
+    travel 4.seconds
 
     # get as stream
     result1 = as_client1.push
@@ -254,7 +254,7 @@ class SessionBasicTest < ActiveSupport::TestCase
 
     Group.create(name: "SomeTicketCreateGroup::#{rand(999_999)}", active: true)
 
-    sleep 4
+    travel 4.seconds
 
     # get as stream
     result1 = ticket_create_client1.push
diff --git a/test/unit/session_basic_ticket_test.rb b/test/unit/session_basic_ticket_test.rb
index c0e16fe4e..05949e9a4 100644
--- a/test/unit/session_basic_ticket_test.rb
+++ b/test/unit/session_basic_ticket_test.rb
@@ -38,17 +38,17 @@ class SessionBasicTicketTest < ActiveSupport::TestCase
     assert(!result1, 'check ticket_overview_index - recall')
 
     # next check should be empty / no changes
-    sleep 3
+    travel 3.seconds
     result1 = client1.push
     assert(!result1, 'check ticket_overview_index - recall 2')
 
     # create ticket
     ticket = Ticket.create(title: '12323', group_id: 1, priority_id: 1, state_id: 1, customer_id: 1)
-    sleep 3
+    travel 3.seconds
 
     result1 = client1.push
     assert(result1, 'check ticket_overview_index - recall 3')
-    sleep 3
+    travel 3.seconds
 
     # chnage overview
     overviews = Ticket::Overviews.all(
diff --git a/test/unit/session_collections_test.rb b/test/unit/session_collections_test.rb
index f67855422..6933a33f4 100644
--- a/test/unit/session_collections_test.rb
+++ b/test/unit/session_collections_test.rb
@@ -67,7 +67,7 @@ class SessionCollectionsTest < ActiveSupport::TestCase
     assert(check_if_collection_exists(result1, :Role), 'check collections - after init')
     assert(check_if_collection_exists(result1, :Signature), 'check collections - after init')
     assert(check_if_collection_exists(result1, :EmailAddress), 'check collections - after init')
-    sleep 1
+    travel 1.second
     result2 = collection_client2.push
     assert(result2, 'check collections')
     assert(check_if_collection_exists(result2, :Group), 'check collections - after init')
@@ -108,7 +108,7 @@ class SessionCollectionsTest < ActiveSupport::TestCase
     # change collection
     group = Group.first
     group.touch
-    sleep 3
+    travel 3.seconds
 
     # get whole collections
     result1 = collection_client1.push
diff --git a/test/unit/tag_test.rb b/test/unit/tag_test.rb
index 041719301..43b6484cf 100644
--- a/test/unit/tag_test.rb
+++ b/test/unit/tag_test.rb
@@ -184,7 +184,7 @@ class TagTest < ActiveSupport::TestCase
       updated_by_id: 1,
       created_by_id: 1,
     )
-    sleep 2
+    travel 2.seconds
     Tag.tag_add(
       object: 'Ticket',
       o_id: ticket1.id,
@@ -266,7 +266,7 @@ class TagTest < ActiveSupport::TestCase
     assert(tags_ticket2.include?('some tag4'))
 
     # rename tag
-    sleep 2
+    travel 2.seconds
     tag_item3 = Tag::Item.find_by(name: 'some tag3')
     Tag::Item.rename(
       id: tag_item3.id,
@@ -300,7 +300,7 @@ class TagTest < ActiveSupport::TestCase
     assert(tags_ticket2.include?('some tag4'))
 
     # merge tags
-    sleep 2
+    travel 2.seconds
     Tag::Item.rename(
       id: tag_item3.id,
       name: 'some tag2',
@@ -333,7 +333,7 @@ class TagTest < ActiveSupport::TestCase
     assert_not(Tag::Item.find_by(id: tag_item3.id))
 
     # remove tag item
-    sleep 2
+    travel 2.seconds
     tag_item4 = Tag::Item.find_by(name: 'some TAG4')
     Tag::Item.remove(tag_item4.id)
 
diff --git a/test/unit/ticket_ref_object_touch_test.rb b/test/unit/ticket_ref_object_touch_test.rb
index 3b232f8b3..3f437f71c 100644
--- a/test/unit/ticket_ref_object_touch_test.rb
+++ b/test/unit/ticket_ref_object_touch_test.rb
@@ -90,7 +90,7 @@ class TicketRefObjectTouchTest < ActiveSupport::TestCase
       assert(false, 'organization1.updated_at has not been updated')
     end
 
-    sleep 4
+    travel 4.seconds
 
     delete = ticket.destroy
     assert(delete, 'ticket destroy')
@@ -113,7 +113,7 @@ class TicketRefObjectTouchTest < ActiveSupport::TestCase
 
   test 'c - check if customer (not organization) has been updated' do
 
-    sleep 6
+    travel 6.seconds
     ticket = Ticket.create(
       title: "some title2\n äöüß",
       group: Group.lookup(name: 'Users'),
@@ -143,7 +143,7 @@ class TicketRefObjectTouchTest < ActiveSupport::TestCase
       assert(true, 'organization1.updated_at has not been updated')
     end
 
-    sleep 4
+    travel 4.seconds
 
     delete = ticket.destroy
     assert(delete, 'ticket destroy')
diff --git a/test/unit/ticket_selector_test.rb b/test/unit/ticket_selector_test.rb
index 218dbbeac..1a4dbe183 100644
--- a/test/unit/ticket_selector_test.rb
+++ b/test/unit/ticket_selector_test.rb
@@ -100,7 +100,7 @@ class TicketSelectorTest < ActiveSupport::TestCase
     assert(ticket1, 'ticket created')
     assert_equal(ticket1.customer.id, customer1.id)
     assert_equal(ticket1.organization.id, organization1.id)
-    sleep 1
+    travel 1.second
 
     ticket2 = Ticket.create!(
       title: 'some title2',
@@ -116,7 +116,7 @@ class TicketSelectorTest < ActiveSupport::TestCase
     assert(ticket2, 'ticket created')
     assert_equal(ticket2.customer.id, customer2.id)
     assert_equal(ticket2.organization_id, nil)
-    sleep 1
+    travel 1.second
 
     ticket3 = Ticket.create!(
       title: 'some title3',
@@ -133,7 +133,7 @@ class TicketSelectorTest < ActiveSupport::TestCase
     assert(ticket3, 'ticket created')
     assert_equal(ticket3.customer.id, customer2.id)
     assert_equal(ticket3.organization_id, nil)
-    sleep 1
+    travel 1.second
 
     # search not matching
     condition = {
diff --git a/test/unit/ticket_test.rb b/test/unit/ticket_test.rb
index f9012db71..db6e9d6c1 100644
--- a/test/unit/ticket_test.rb
+++ b/test/unit/ticket_test.rb
@@ -43,7 +43,7 @@ class TicketTest < ActiveSupport::TestCase
     assert_equal(ticket.close_at, nil, 'ticket.close_at verify - inbound')
 
     # create inbound article #2
-    sleep 2
+    travel 2.seconds
     article_inbound2 = Ticket::Article.create(
       ticket_id: ticket.id,
       from: 'some_sender@example.com',
@@ -91,7 +91,7 @@ class TicketTest < ActiveSupport::TestCase
     assert_equal(ticket.close_at, nil, 'ticket.close_at verify - note')
 
     # create outbound article
-    sleep 2
+    travel 2.seconds
     article_outbound = Ticket::Article.create(
       ticket_id: ticket.id,
       from: 'some_recipient@example.com',
@@ -139,7 +139,7 @@ class TicketTest < ActiveSupport::TestCase
     assert_equal(ticket.close_at, nil, 'ticket.close_at verify - outbound')
 
     # create inbound article #4
-    sleep 2
+    travel 2.seconds
     article_inbound4 = Ticket::Article.create(
       ticket_id: ticket.id,
       from: 'some_sender@example.com',
@@ -207,7 +207,7 @@ class TicketTest < ActiveSupport::TestCase
     )
     assert_equal(Ticket.latest_change.to_s, ticket1.updated_at.to_s)
 
-    sleep 1
+    travel 1.second
 
     ticket2 = Ticket.create(
       title: 'latest change 2',
@@ -220,13 +220,13 @@ class TicketTest < ActiveSupport::TestCase
     )
     assert_equal(Ticket.latest_change.to_s, ticket2.updated_at.to_s)
 
-    sleep 1
+    travel 1.second
 
     ticket1.title = 'latest change 1 - 1'
     ticket1.save
     assert_equal(Ticket.latest_change.to_s, ticket1.updated_at.to_s)
 
-    sleep 1
+    travel 1.second
 
     ticket1.touch
     assert_equal(Ticket.latest_change.to_s, ticket1.updated_at.to_s)