diff --git a/.rubocop.yml b/.rubocop.yml
index 0d0665b31c3..05a6af3d54f 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -86,8 +86,5 @@ Style/PreferredHashMethods:
 Minitest/AssertEmptyLiteral:
   Enabled: true
 
-Minitest/AssertNil:
-  Enabled: true
-
 Minitest/RefuteNil:
   Enabled: true
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 678b069f6d8..cc287e6429e 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -139,10 +139,6 @@ Lint/Void:
     - 'app/models/nic/base.rb'
     - 'app/services/name_generator.rb'
 
-# Offense count: 28
-# Cop supports --auto-correct.
-Minitest/AssertEmpty:
-  Enabled: false
 
 # Offense count: 26
 # Cop supports --auto-correct.
diff --git a/test/controllers/api/v2/config_reports_controller_test.rb b/test/controllers/api/v2/config_reports_controller_test.rb
index a8f5ad5125b..2d8ebef01cd 100644
--- a/test/controllers/api/v2/config_reports_controller_test.rb
+++ b/test/controllers/api/v2/config_reports_controller_test.rb
@@ -131,7 +131,7 @@ def test_create_duplicate
     assert_response :success
     assert_not_nil assigns(:config_reports)
     reports = ActiveSupport::JSON.decode(@response.body)
-    assert reports['results'].empty?
+    assert_empty reports['results']
     assert_equal 0, reports['results'].count
   end
 
diff --git a/test/controllers/api/v2/hostgroups_controller_test.rb b/test/controllers/api/v2/hostgroups_controller_test.rb
index f3ffe8952cd..8d9f566fa93 100644
--- a/test/controllers/api/v2/hostgroups_controller_test.rb
+++ b/test/controllers/api/v2/hostgroups_controller_test.rb
@@ -25,7 +25,7 @@ def valid_attrs_with_root(extra_attrs = {})
     assert_not_nil assigns(:hostgroups)
     hostgroups = ActiveSupport::JSON.decode(@response.body)
     assert !hostgroups.empty?
-    assert hostgroups['results'].select { |h| h.has_key?('parameters') }.empty?
+    assert_empty hostgroups['results'].select { |h| h.has_key?('parameters') }
   end
 
   test "should get index with parameters" do
diff --git a/test/controllers/api/v2/users_controller_test.rb b/test/controllers/api/v2/users_controller_test.rb
index a2583d59471..7d6aff0d889 100644
--- a/test/controllers/api/v2/users_controller_test.rb
+++ b/test/controllers/api/v2/users_controller_test.rb
@@ -206,7 +206,7 @@ def user_one_as_anonymous_viewer
   test "#index should not show hidden users" do
     get :index, params: { :search => "login == #{users(:anonymous).login}" }
     results = ActiveSupport::JSON.decode(@response.body)
-    assert results['results'].empty?, results.inspect
+    assert_empty results['results']
   end
 
   test "#find_resource should not return hidden users" do
diff --git a/test/controllers/compute_resources_controller_test.rb b/test/controllers/compute_resources_controller_test.rb
index d055abd369e..4e4739c38f3 100644
--- a/test/controllers/compute_resources_controller_test.rb
+++ b/test/controllers/compute_resources_controller_test.rb
@@ -96,7 +96,7 @@ class ComputeResourcesControllerTest < ActionController::TestCase
     setup_user "edit"
     put :update, params: { :id => @compute_resource.to_param, :compute_resource => {:name => "editing_self", :password => ''} }, session: set_session_user
     @compute_resource = ComputeResource.unscoped.find(@compute_resource.id)
-    assert @compute_resource.password.empty?
+    assert_empty @compute_resource.password
   end
 
   test "should not get edit when restricted" do
@@ -162,7 +162,7 @@ class ComputeResourcesControllerTest < ActionController::TestCase
     test 'valid fields' do
       get :index, params: { :search => 'name = openstack' }, session: set_session_user
       assert_response :success
-      assert flash.empty?
+      assert_empty flash
     end
 
     test 'invalid fields' do
diff --git a/test/controllers/hostgroups_controller_test.rb b/test/controllers/hostgroups_controller_test.rb
index 697729e0e81..5a619f41e7b 100644
--- a/test/controllers/hostgroups_controller_test.rb
+++ b/test/controllers/hostgroups_controller_test.rb
@@ -99,7 +99,7 @@ def setup_user(operation, type = 'hostgroups')
       put :update, params: { :commit => "Update", :id => hostgroup.id, :hostgroup => {:root_pass => '', :name => hostgroup.name} }, session: set_session_user
     end
     hostgroup = Hostgroup.find(hostgroup.id)
-    assert hostgroup.root_pass.empty?
+    assert_empty hostgroup.root_pass
   end
 
   test "hostgroup rename changes matcher" do
diff --git a/test/controllers/hosts_controller_test.rb b/test/controllers/hosts_controller_test.rb
index 4223378077b..21a68003240 100644
--- a/test/controllers/hosts_controller_test.rb
+++ b/test/controllers/hosts_controller_test.rb
@@ -761,7 +761,7 @@ def set_remote_user_to(user)
 
     test 'destroy' do
       multiple_hosts_submit_request('destroy', [@host1.id, @host2.id], 'Destroyed selected hosts')
-      assert Host.where(:id => [@host1.id, @host2.id]).empty?
+      assert_empty Host.where(:id => [@host1.id, @host2.id])
     end
 
     test 'disable notifications' do
@@ -968,7 +968,7 @@ class Host::Valid < Host::Managed; end
   test 'blank root password submitted in host does erase existing password' do
     put :update, params: { :commit => "Update", :id => @host.name, :host => {:root_pass => '' } }, session: set_session_user
     @host = Host.find(@host.id)
-    assert @host.root_pass.empty?
+    assert_empty @host.root_pass
   end
 
   test "host should get bmc status" do
@@ -996,7 +996,7 @@ class Host::Valid < Host::Managed; end
     assert bmc1.save
     put :update, params: { :commit => "Update", :id => @host.name, :host => {:interfaces_attributes => {"0" => {:id => bmc1.id, :password => ''} } } }, session: set_session_user
     @host = Host.find(@host.id)
-    assert @host.interfaces.bmc.first.password.empty?
+    assert_empty @host.interfaces.bmc.first.password
   end
 
   # To test that work-around for Rails bug - https://github.com/rails/rails/issues/11031
diff --git a/test/controllers/operatingsystems_controller_test.rb b/test/controllers/operatingsystems_controller_test.rb
index 0e3dc811a7e..1336eff2f5a 100644
--- a/test/controllers/operatingsystems_controller_test.rb
+++ b/test/controllers/operatingsystems_controller_test.rb
@@ -108,7 +108,7 @@ def setup_os_user
     test 'valid fields' do
       get :index, params: { :search => 'name = centos' }, session: set_session_user
       assert_response :success
-      assert flash.empty?
+      assert_empty flash
     end
 
     test 'invalid fields' do
diff --git a/test/controllers/provisioning_templates_controller_test.rb b/test/controllers/provisioning_templates_controller_test.rb
index 55270802fe7..8c061ebaedc 100644
--- a/test/controllers/provisioning_templates_controller_test.rb
+++ b/test/controllers/provisioning_templates_controller_test.rb
@@ -139,7 +139,7 @@ class ProvisioningTemplatesControllerTest < ActionController::TestCase
       ProxyAPI::TFTP.any_instance.expects(:create_default).with(regexp_matches(/^PXE.*/), has_entry(:menu, regexp_matches(/ks=http:\/\/foreman.unattended.url\/unattended\/template/))).returns(true).times(3)
       get :build_pxe_default, session: set_session_user
       assert flash[:success].present?
-      assert flash[:error].empty?
+      assert_empty flash[:error]
       assert_redirected_to provisioning_templates_path
     end
 
diff --git a/test/models/compute_resources/compute_resource_test_helpers.rb b/test/models/compute_resources/compute_resource_test_helpers.rb
index 60919ff471e..2c2b00a49b8 100644
--- a/test/models/compute_resources/compute_resource_test_helpers.rb
+++ b/test/models/compute_resources/compute_resource_test_helpers.rb
@@ -124,6 +124,6 @@ def check_vm_attribute_names(cr)
     unexpected_names = normalized_keys - (normalized_keys & allowed_vm_attr_names)
     msg = "Some unexpected attributes detected: #{unexpected_names.join(', ')}."
     msg += "\nMake user you can't use one of names that already exist. If not, please extend ComputeResourceTestHelpers.allowed_vm_attr_names."
-    assert(unexpected_names.empty?, msg)
+    assert_empty(unexpected_names, msg)
   end
 end
diff --git a/test/models/domain_test.rb b/test/models/domain_test.rb
index 268c8632f0f..a0dd7cceb19 100644
--- a/test/models/domain_test.rb
+++ b/test/models/domain_test.rb
@@ -48,7 +48,7 @@ def setup
 
   test "should not destroy if it contains subnets" do
     @domain.subnets.clear
-    assert @domain.subnets.empty?
+    assert_empty @domain.subnets
     @domain.subnets << Subnet.first
     assert !@domain.destroy
     assert_match /is used by/, @domain.errors.full_messages.join("\n")
@@ -81,7 +81,7 @@ def create_a_host
 
   test "should query local nameservers when enabled" do
     Setting['query_local_nameservers'] = true
-    assert Domain.first.nameservers.empty?
+    assert_empty Domain.first.nameservers
   end
 
   test "should query remote nameservers from domain SOA" do
diff --git a/test/models/medium_test.rb b/test/models/medium_test.rb
index 74e80d36d4b..cab87ab3979 100644
--- a/test/models/medium_test.rb
+++ b/test/models/medium_test.rb
@@ -56,7 +56,7 @@ class MediumTest < ActiveSupport::TestCase
 
     test "can't be blank" do
       @medium.path = '  '
-      assert @medium.path.strip.empty?
+      assert_empty @medium.path.strip
       refute_valid @medium
     end
 
diff --git a/test/models/orchestration/dhcp_test.rb b/test/models/orchestration/dhcp_test.rb
index 458c52781f5..feb7cad8e52 100644
--- a/test/models/orchestration/dhcp_test.rb
+++ b/test/models/orchestration/dhcp_test.rb
@@ -382,7 +382,7 @@ def host_with_loader(loader)
 
     h.build = true
     assert h.valid?
-    assert h.errors.empty?
+    assert_empty h.errors
     assert_equal ["dhcp_create_aa:bb:cc:dd:ee:f1"], h.queue.task_ids
   end
 
diff --git a/test/models/orchestration/tftp_test.rb b/test/models/orchestration/tftp_test.rb
index f0baa984f59..f9d2fbde25a 100644
--- a/test/models/orchestration/tftp_test.rb
+++ b/test/models/orchestration/tftp_test.rb
@@ -272,7 +272,7 @@ class TFTPOrchestrationTest < ActiveSupport::TestCase
 
     result = h.send(:generate_pxe_template, :ZTP)
     assert result.blank?
-    assert h.errors.empty?
+    assert_empty h.errors
   end
 
   test 'should rebuild tftp IPv4' do
diff --git a/test/models/shared/taxonomies_base_test.rb b/test/models/shared/taxonomies_base_test.rb
index ac26751908f..260cfbfbb90 100644
--- a/test/models/shared/taxonomies_base_test.rb
+++ b/test/models/shared/taxonomies_base_test.rb
@@ -298,7 +298,7 @@ module TaxonomiesBaseTest
       taxonomy = taxonomy_class.create :name => "rack1", :parent_id => parent.id
       # no hosts were assigned to taxonomy, so no missing ids need to be selected
       taxonomy.need_to_be_selected_ids.each do |k, v|
-        assert v.empty?
+        assert_empty v
       end
     end
 
diff --git a/test/models/template_test.rb b/test/models/template_test.rb
index 94d29c8bb1b..f69a24653a7 100644
--- a/test/models/template_test.rb
+++ b/test/models/template_test.rb
@@ -438,7 +438,7 @@ class TemplateTest < ActiveSupport::TestCase
       test 'should initialize a new template' do
         template = ProvisioningTemplate.find_without_collision(:name, 'new template')
         assert template.new_record?
-        assert template.errors.empty?
+        assert_empty template.errors
       end
 
       test 'should return existing template in current context' do
diff --git a/test/models/token/build_test.rb b/test/models/token/build_test.rb
index a9ea92300b5..7267d6265e9 100644
--- a/test/models/token/build_test.rb
+++ b/test/models/token/build_test.rb
@@ -15,7 +15,7 @@ class Token::BuildTest < ActiveSupport::TestCase
     host.create_token(:value => 'aaaaaa', :expires => Time.now.utc + 1.minute)
     assert_instance_of Token::Build, host.token
     host.token = nil
-    assert Token.where(:value => 'aaaaaa', :host_id => host.id).empty?
+    assert_empty Token.where(:value => 'aaaaaa', :host_id => host.id)
   end
 
   test "a host cannot delete tokens for other hosts" do
diff --git a/test/models/user_test.rb b/test/models/user_test.rb
index 80ff082023c..7bbc43df018 100644
--- a/test/models/user_test.rb
+++ b/test/models/user_test.rb
@@ -176,12 +176,12 @@ def setup
     # Mail enabled
     u1 = FactoryBot.create(:user, :mail => 'foo@bar.baz', :mail_enabled => nil)
     u2 = FactoryBot.create(:user, :mail => 'foo@bar.baz', :mail_enabled => '')
-    assert User.with_enabled_email.where(login: [u1, u2].map(&:login)).empty?
+    assert_empty User.with_enabled_email.where(login: [u1, u2].map(&:login))
 
     # Mail missing
     u1 = FactoryBot.create(:user, :mail => '', :mail_enabled => true)
     u2 = FactoryBot.create(:user, :mail => nil, :mail_enabled => true)
-    assert User.with_enabled_email.where(login: [u1, u2].map(&:login)).empty?
+    assert_empty User.with_enabled_email.where(login: [u1, u2].map(&:login))
 
     # Disabled
     u1 = FactoryBot.create(:user, :mail => 'foo@bar.baz', :mail_enabled => true, :disabled => false)
diff --git a/test/unit/foreman/model/ovirt_test.rb b/test/unit/foreman/model/ovirt_test.rb
index f5af5fc3900..5d014486cc6 100644
--- a/test/unit/foreman/model/ovirt_test.rb
+++ b/test/unit/foreman/model/ovirt_test.rb
@@ -87,7 +87,7 @@ def new_ovirt_cr(proto = 'http')
     record.stubs(:datacenters).returns(['example', 1])
     RestClient.expects(:post).never()
     assert record.test_connection
-    assert record.errors.empty?
+    assert_empty record.errors
   end
 
   test "test_connection should detect 302 HTTPS redirect with HTTP url and fail" do
diff --git a/test/unit/net/dhcp_test.rb b/test/unit/net/dhcp_test.rb
index 471aa0f6ed1..bca53732c79 100644
--- a/test/unit/net/dhcp_test.rb
+++ b/test/unit/net/dhcp_test.rb
@@ -88,7 +88,7 @@ class DhcpTest < ActiveSupport::TestCase
     record1 = Net::DHCP::Record.new(:hostname => "test1", :mac => "aa:bb:cc:dd:ee:ff",
                                     :network => "127.0.0.0", :ip => "127.0.0.1",
                                     "proxy" => subnets(:one).dhcp_proxy)
-    assert record1.conflicts.empty?
+    assert_empty record1.conflicts
   end
 
   test "dhcp record validation should return false when proxy returns nil" do
@@ -137,7 +137,7 @@ class DhcpTest < ActiveSupport::TestCase
     record1 = Net::DHCP::Record.new(:hostname => "discovered_host1", :mac => "aa:bb:cc:dd:ee:01",
                                     :network => "127.0.0.0", :ip => "127.0.0.2",
                                     "proxy" => subnets(:one).dhcp_proxy)
-    assert record1.conflicts.empty?
+    assert_empty record1.conflicts
     assert record1.valid?
   end
 
@@ -160,7 +160,7 @@ class DhcpTest < ActiveSupport::TestCase
                                     "proxy" => subnets(:one).dhcp_proxy)
     assert_equal "lease", subnets(:one).dhcp_proxy.record("127.0.0.0", "aa:bb:cc:dd:ee:01").type
     assert_equal "lease", subnets(:one).dhcp_proxy.records_by_ip("127.0.0.0", "127.0.0.2").first.type
-    assert rec.conflicts.empty?
+    assert_empty rec.conflicts
   end
 
   test "dhcp record and reservation with same MAC is not a conflict" do
diff --git a/test/unit/role_lock_test.rb b/test/unit/role_lock_test.rb
index 63aa5f8ddb4..6cfc82e0421 100644
--- a/test/unit/role_lock_test.rb
+++ b/test/unit/role_lock_test.rb
@@ -79,7 +79,7 @@ def find_role(name)
     refute find_role("Customized CRUD hosts")
     original_role = find_role(original_name)
     assert_equal original_role.id, role.id
-    assert original_role.permission_diff(perms).empty?
+    assert_empty original_role.permission_diff(perms)
   end
 
   test "should process existing role with origin and removed permissions" do
@@ -91,7 +91,7 @@ def find_role(name)
     refute find_role("Customized CRUD hosts")
     original_role = find_role(original_name)
     assert_equal original_role.id, role.id
-    assert original_role.permission_diff(perms).empty?
+    assert_empty original_role.permission_diff(perms)
   end
 
   test "should process existing role with unchanged permissions list" do