diff --git a/test/functional/workflows_controller_test.rb b/test/functional/workflows_controller_test.rb
index cf9ab2eae..cc535c42d 100644
--- a/test/functional/workflows_controller_test.rb
+++ b/test/functional/workflows_controller_test.rb
@@ -145,8 +145,8 @@ class WorkflowsControllerTest < Redmine::ControllerTest
     assert_response 302
 
     assert_equal 3, WorkflowTransition.where(:tracker_id => 1, :role_id => 2).count
-    assert_not_nil  WorkflowTransition.where(:role_id => 2, :tracker_id => 1, :old_status_id => 3, :new_status_id => 2).first
-    assert_nil      WorkflowTransition.where(:role_id => 2, :tracker_id => 1, :old_status_id => 5, :new_status_id => 4).first
+    assert          WorkflowTransition.where(:role_id => 2, :tracker_id => 1, :old_status_id => 3, :new_status_id => 2).exists?
+    assert_not      WorkflowTransition.where(:role_id => 2, :tracker_id => 1, :old_status_id => 5, :new_status_id => 4).exists?
   end
 
   def test_post_edit_with_allowed_statuses_for_new_issues
diff --git a/test/unit/default_data_test.rb b/test/unit/default_data_test.rb
index ddb92d31c..865a994dc 100644
--- a/test/unit/default_data_test.rb
+++ b/test/unit/default_data_test.rb
@@ -36,11 +36,11 @@ class DefaultDataTest < ActiveSupport::TestCase
   def test_load
     clear_data
     assert Redmine::DefaultData::Loader::load('en')
-    assert_not_nil DocumentCategory.first
-    assert_not_nil IssuePriority.first
-    assert_not_nil TimeEntryActivity.first
-    assert_not_nil WorkflowTransition.first
-    assert_not_nil Query.first
+    assert DocumentCategory.exists?
+    assert IssuePriority.exists?
+    assert TimeEntryActivity.exists?
+    assert WorkflowTransition.exists?
+    assert Query.exists?
   end
 
   def test_load_for_all_language
@@ -48,10 +48,10 @@ class DefaultDataTest < ActiveSupport::TestCase
       clear_data
       begin
         assert Redmine::DefaultData::Loader::load(lang, :workflow => false)
-        assert_not_nil DocumentCategory.first
-        assert_not_nil IssuePriority.first
-        assert_not_nil TimeEntryActivity.first
-        assert_not_nil Query.first
+        assert DocumentCategory.exists?
+        assert IssuePriority.exists?
+        assert TimeEntryActivity.exists?
+        assert Query.exists?
       rescue ActiveRecord::RecordInvalid => e
         assert false, ":#{lang} default data is invalid (#{e.message})."
       end
diff --git a/test/unit/document_category_test.rb b/test/unit/document_category_test.rb
index ca4d77491..8be12dbe9 100644
--- a/test/unit/document_category_test.rb
+++ b/test/unit/document_category_test.rb
@@ -40,14 +40,14 @@ class DocumentCategoryTest < ActiveSupport::TestCase
   end
 
   def test_default
-    assert_nil DocumentCategory.where(:is_default => true).first
+    assert_not DocumentCategory.where(:is_default => true).exists?
     e = Enumeration.find_by_name('Technical documentation')
     e.update(:is_default => true)
     assert_equal 3, DocumentCategory.default.id
   end
 
   def test_force_default
-    assert_nil DocumentCategory.where(:is_default => true).first
+    assert_not DocumentCategory.where(:is_default => true).exists?
     assert_equal 1, DocumentCategory.default.id
   end
 end
diff --git a/test/unit/enumeration_test.rb b/test/unit/enumeration_test.rb
index 5c897f311..247a3c4c5 100644
--- a/test/unit/enumeration_test.rb
+++ b/test/unit/enumeration_test.rb
@@ -92,7 +92,7 @@ class EnumerationTest < ActiveSupport::TestCase
 
   def test_destroy_with_reassign
     Enumeration.find(4).destroy(Enumeration.find(6))
-    assert_nil Issue.where(:priority_id => 4).first
+    assert_not Issue.where(:priority_id => 4).exists?
     assert_equal 6, Enumeration.find(6).objects_count
   end
 
diff --git a/test/unit/issue_status_test.rb b/test/unit/issue_status_test.rb
index e4000c14a..7a043aa62 100644
--- a/test/unit/issue_status_test.rb
+++ b/test/unit/issue_status_test.rb
@@ -49,8 +49,8 @@ class IssueStatusTest < ActiveSupport::TestCase
     assert_difference 'IssueStatus.count', -1 do
       assert status.destroy
     end
-    assert_nil WorkflowTransition.where(:old_status_id => status.id).first
-    assert_nil WorkflowTransition.where(:new_status_id => status.id).first
+    assert_not WorkflowTransition.where(:old_status_id => status.id).exists?
+    assert_not WorkflowTransition.where(:new_status_id => status.id).exists?
   end
 
   def test_destroy_status_in_use
diff --git a/test/unit/issue_test.rb b/test/unit/issue_test.rb
index aea76e34f..d82f6e079 100644
--- a/test/unit/issue_test.rb
+++ b/test/unit/issue_test.rb
@@ -248,14 +248,14 @@ class IssueTest < ActiveSupport::TestCase
   def test_anonymous_should_not_see_private_issues_with_issues_visibility_set_to_default
     Role.anonymous.update!(:issues_visibility => 'default')
     issue = Issue.generate!(:author => User.anonymous, :is_private => true)
-    assert_nil Issue.where(:id => issue.id).visible(User.anonymous).first
+    assert_not Issue.where(:id => issue.id).visible(User.anonymous).exists?
     assert !issue.visible?(User.anonymous)
   end
 
   def test_anonymous_should_not_see_private_issues_with_issues_visibility_set_to_own
     assert Role.anonymous.update!(:issues_visibility => 'own')
     issue = Issue.generate!(:author => User.anonymous, :is_private => true)
-    assert_nil Issue.where(:id => issue.id).visible(User.anonymous).first
+    assert_not Issue.where(:id => issue.id).visible(User.anonymous).exists?
     assert !issue.visible?(User.anonymous)
   end
 
diff --git a/test/unit/project_test.rb b/test/unit/project_test.rb
index 5fc3743d5..5198d040a 100644
--- a/test/unit/project_test.rb
+++ b/test/unit/project_test.rb
@@ -237,9 +237,9 @@ class ProjectTest < ActiveSupport::TestCase
     # make sure that the project non longer exists
     assert_raise(ActiveRecord::RecordNotFound) {Project.find(@ecookbook.id)}
     # make sure related data was removed
-    assert_nil Member.where(:project_id => @ecookbook.id).first
-    assert_nil Board.where(:project_id => @ecookbook.id).first
-    assert_nil Issue.where(:project_id => @ecookbook.id).first
+    assert_not Member.where(:project_id => @ecookbook.id).exists?
+    assert_not Board.where(:project_id => @ecookbook.id).exists?
+    assert_not Issue.where(:project_id => @ecookbook.id).exists?
   end
 
   def test_destroy_should_destroy_subtasks
diff --git a/test/unit/wiki_redirect_test.rb b/test/unit/wiki_redirect_test.rb
index cbdca9309..2f78e8c20 100644
--- a/test/unit/wiki_redirect_test.rb
+++ b/test/unit/wiki_redirect_test.rb
@@ -95,6 +95,6 @@ class WikiRedirectTest < ActiveSupport::TestCase
     assert WikiRedirect.create(:wiki => @wiki, :title => 'An_old_page', :redirects_to => 'Original_title')
 
     @original.destroy
-    assert_nil @wiki.redirects.first
+    assert_not @wiki.redirects.exists?
   end
 end