diff --git a/test/api/campuses_test.rb b/test/api/campuses_test.rb
index 3a0da3534..638d490df 100644
--- a/test/api/campuses_test.rb
+++ b/test/api/campuses_test.rb
@@ -50,12 +50,7 @@ def test_student_cannot_post_campuses
     }
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: auth_token(user_student),
-      username: user_student.username
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: auth_token(user_student), username: user_student.username)
 
     post_json "/api/campuses", data_to_post
     assert_equal 403, last_response.status
@@ -85,12 +80,7 @@ def test_student_cannot_put_campuses
     }
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: auth_token(user_student),
-      username: user_student.username
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: auth_token(user_student), username: user_student.username)
 
     put_json "/api/campuses/#{data_to_put[:campus].id}", data_to_put
     assert_equal 403, last_response.status
@@ -122,12 +112,7 @@ def test_student_delete_campus
     campus = FactoryBot.create(:campus, mode: 'timetable')
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: auth_token(user_student),
-      username: user_student.username
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: auth_token(user_student), username: user_student.username)
 
     # perform the delete
     delete_json "/api/campuses/#{campus.id}"
diff --git a/test/api/csv_test.rb b/test/api/csv_test.rb
index c7ccb1c7b..053a9166e 100644
--- a/test/api/csv_test.rb
+++ b/test/api/csv_test.rb
@@ -94,11 +94,7 @@ def test_download_csv_all_task_definitions_unit_with_incorrect_auth_token
     unit_id_to_test = 'string'
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: "wrong_token"
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: "wrong token", username: 'aadmin')
 
     # perform the get
     get "/api/csv/task_definitions?unit_id=#{unit_id_to_test}"
@@ -157,11 +153,7 @@ def test_csv_upload_all_task_definitions_unit_incorrect_auth_token
     }
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: "wrong_token"
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(username: 'aadmin', auth_token: "wrong_token")
 
     # perform the POST
     post "/api/csv/task_definitions", data_to_post
@@ -365,13 +357,8 @@ def test_download_csv_all_students_in_unit_with_incorrect_auth_token
 
     unit_id_to_test = '1'
 
-    # auth_token to header
-    auth_data_to_header = {
-      auth_token: 'wrong_token'
-    }
-
     # auth_token and username added to header
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(username: 'aadmin', auth_token: 'wrong_token')
 
     # perform the get
     get "/api/csv/units/#{unit_id_to_test}"
@@ -411,12 +398,7 @@ def test_csv_upload_all_students_in_unit
     }
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: auth_token(unit.main_convenor_user),
-      username: unit.main_convenor_user.username
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: auth_token(unit.main_convenor_user), username: unit.main_convenor_user.username)
 
     # perform the POST
     post "/api/csv/units/#{unit.id}", data_to_post
@@ -439,12 +421,8 @@ def test_csv_upload_all_students_in_unit_incorrect_auth_token
       file: upload_file_csv('test_files/csv_test_files/COS10001-Students.csv')
     }
 
-        # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: "wrong_token"
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    # auth_token and username added to header
+    add_auth_header_for(username: 'aadmin', auth_token: "wrong_token")
 
     # perform the POST
     post "/api/csv/units/#{unit.id}", data_to_post
@@ -499,12 +477,7 @@ def test_csv_upload_all_students_in_unit_incorrect_file_pdf
     }
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: auth_token(unit.main_convenor_user),
-      username: unit.main_convenor_user.username
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(user: unit.main_convenor_user)
 
     # perform the POST
     post "/api/csv/units/#{unit.id}", data_to_post
@@ -522,12 +495,7 @@ def test_csv_upload_all_students_in_unit_no_file
     }
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: auth_token(unit.main_convenor_user),
-      username: unit.main_convenor_user.username
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: auth_token(unit.main_convenor_user), username: unit.main_convenor_user.username)
 
     # perform the POST
     post "/api/csv/units/#{unit.id}", data_to_post
@@ -567,12 +535,7 @@ def test_csv_upload_students_un_enroll_in_unit
     }
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: auth_token(unit.main_convenor_user),
-      username: unit.main_convenor_user.username
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: auth_token(unit.main_convenor_user), username: unit.main_convenor_user.username)
 
     user_id_check = unit.projects.last.user_id
 
@@ -598,11 +561,7 @@ def test_csv_upload_students_un_enroll_in_unit_incorrect_auth_token
     }
 
     # auth_token and username added to header
-    auth_data_to_header = {
-      auth_token: 'wrong_token'
-    }
-
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(username: 'aadmin', auth_token: "wrong_token")
 
     # perform the POST to withdraw user from the unit
     post "/api/csv/units/#{unit.id}/withdraw", data_to_post
@@ -620,8 +579,9 @@ def test_csv_upload_students_un_enroll_in_unit_incorrect_auth_token
   #POST /api/csv/units/{id}/withdraw
   def test_csv_upload_students_un_enroll_in_unit_empty_auth_token
 
-        unit = FactoryBot.create(:unit, code: 'COS10001', with_students: false, stream_count: 0)
-    unit.import_users_from_csv test_file_path 'csv_test_files/COS10001-Students.csv'
+    unit = FactoryBot.create(:unit, code: 'COS10001', with_students: false, stream_count: 0)
+    response = unit.import_users_from_csv test_file_path 'csv_test_files/COS10001-Students.csv'
+    assert_equal 1, unit.projects.count, response
 
 
     unit_id_to_test = '1'
@@ -689,7 +649,7 @@ def test_csv_upload_students_un_enroll_in_unit_empty_unit_id
     }
 
     # auth_token and username added to header
-    add_auth_header_for(user: User.first)
+    add_auth_header_for(user: unit.main_convenor_user)
 
     user_id_check = unit.projects.last.user_id
 
@@ -886,12 +846,8 @@ def test_download_csv_all_student_tasks_in_unit_with_incorrect_auth_token
 
     unit_id_to_test = '1'
 
-   auth_data_to_header = {
-      auth_token: 'wrong_token'
-    }
-
     # Add authentication token to header
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: 'wrong_token')
 
     # perform the get
     get "/api/csv/units/#{unit_id_to_test}/task_completion"
@@ -993,12 +949,8 @@ def test_download_csv_stats_tutor_assessed_with_incorrect_auth_token
 
     unit_id_to_test = '1'
 
-   auth_data_to_header = {
-      auth_token: 'wrong_token'
-    }
-
     # Add authentication token to header
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(username: 'aadmin', auth_token: 'wrong_token')
 
     # perform the get
     get "/api/csv/units/#{unit_id_to_test}/tutor_assessments"
@@ -1049,12 +1001,8 @@ def test_download_csv_all_users
   #GET /api/csv/users
   def test_download_csv_all_users_with_incorrect_auth_token
 
-    auth_data_to_header = {
-      auth_token: 'wrong_token'
-    }
-
     # Add authentication token to header
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(username: 'aadmin', auth_token: 'wrong_token')
 
     # perform the get
     get "/api/csv/users"
@@ -1109,12 +1057,8 @@ def test_csv_upload_users_incorrect_auth_token
       file: upload_file_csv('test_files/csv_test_files/doubtfire_users.csv')
     }
 
-   auth_data_to_header = {
-      auth_token: 'wrong_token'
-    }
-
     # Add authentication token to header
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(username: 'aadmin', auth_token: 'wrong_token')
 
     # perform the POST to withdraw user from the unit
     post "/api/csv/users", data_to_post
diff --git a/test/api/groups_api_test.rb b/test/api/groups_api_test.rb
index b39f8c948..1e7459d1f 100644
--- a/test/api/groups_api_test.rb
+++ b/test/api/groups_api_test.rb
@@ -168,7 +168,7 @@ def test_pdf_comment_on_group_task
     post "/api/projects/#{project.id}/task_def_id/#{td.id}/comments", comment_data
 
     assert_equal 201, last_response.status
-    assert File.exists?(TaskComment.last.attachment_path)
+    assert File.exist?(TaskComment.last.attachment_path)
 
     td.destroy
     group.destroy
@@ -295,7 +295,7 @@ def test_create_group
 
     # Add username and auth_token to Header
     add_auth_header_for(user: unit.main_convenor_user)
-    
+
     # Try again as convenor
     post "/api/units/#{unit.id}/group_sets/#{gs_response['id']}/groups/#{group_response['id']}/members", {project_id: project.id}
 
@@ -318,7 +318,7 @@ def test_group_student_count
 
   def test_group_switch_tutorial
     unit = FactoryBot.create :unit, group_sets: 1, groups: [{gs: 0, students: 0}]
-    
+
     gs = unit.group_sets.first
     gs.update keep_groups_in_same_class: true, allow_students_to_manage_groups: true
     group1 = gs.groups.first
@@ -330,15 +330,15 @@ def test_group_switch_tutorial
     group1.add_member p2
 
     tutorial = FactoryBot.create :tutorial, unit: unit, campus: nil
-    
+
     refute p1.enrolled_in? tutorial
     refute p2.enrolled_in? tutorial
 
     # Add username and auth_token to Header
     add_auth_header_for(user: unit.main_convenor_user)
-    
+
     put "/api/units/#{unit.id}/group_sets/#{gs.id}/groups/#{group1.id}", { group: {tutorial_id: tutorial.id} }
-    
+
     assert 201, last_response.status
 
     p1.reload
@@ -353,7 +353,7 @@ def test_group_switch_tutorial
 
   def test_group_switch_tutorial_no_student_management
     unit = FactoryBot.create :unit, group_sets: 1, groups: [{gs: 0, students: 0}]
-    
+
     gs = unit.group_sets.first
     gs.update keep_groups_in_same_class: true, allow_students_to_manage_groups: false
     group1 = gs.groups.first
@@ -365,10 +365,10 @@ def test_group_switch_tutorial_no_student_management
     group1.add_member p2
 
     tutorial = FactoryBot.create :tutorial, unit: unit, campus: nil
-    
+
     refute p1.enrolled_in? tutorial
     refute p2.enrolled_in? tutorial
-    
+
     add_auth_header_for(user: unit.main_convenor_user)
     put "/api/units/#{unit.id}/group_sets/#{gs.id}/groups/#{group1.id}", { group: {tutorial_id: tutorial.id} }
 
@@ -386,7 +386,7 @@ def test_group_switch_tutorial_no_student_management
 
   def test_group_switch_tutorial_unenrolled_students
     unit = FactoryBot.create :unit, group_sets: 1, groups: [{gs: 0, students: 0}]
-    
+
     gs = unit.group_sets.first
     gs.update keep_groups_in_same_class: true, allow_students_to_manage_groups: false, capacity: 2
     group1 = gs.groups.first
@@ -400,7 +400,7 @@ def test_group_switch_tutorial_unenrolled_students
     assert group1.at_capacity?
 
     tutorial = FactoryBot.create :tutorial, unit: unit, campus: nil
-    
+
     refute p1.enrolled_in? tutorial
     refute p2.enrolled_in? tutorial
 
diff --git a/test/api/tutorials_test.rb b/test/api/tutorials_test.rb
index c3b951122..379c0e301 100644
--- a/test/api/tutorials_test.rb
+++ b/test/api/tutorials_test.rb
@@ -171,12 +171,8 @@ def test_post_tutorial_with_incorrect_auth_token
       tutorial: tutorial
     }
 
-    auth_data_to_header = {
-      auth_token: 'Incorrect_Auth_Token'
-    }
-
     # Add username and auth_token to Header
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: 'Incorrect_Auth_Token', username: 'aadmin')
 
     # Number of tutorials before POST
     number_of_tutorials = Tutorial.all.length
@@ -963,12 +959,8 @@ def test_put_tutorials_with_incorrect_auth_token
       tutorial: tutorial
     }
 
-    auth_data_to_header = {
-      auth_token: 'Incorrect auth token'
-    }
-
     # Add username and auth_token to Header
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(username: 'aadmin', auth_token: 'Incorrect auth token')
 
     # perform the PUT with incorrect auth token
     put_json "/api/tutorials/#{tutorial_old.id}", data_to_put
@@ -1239,12 +1231,8 @@ def test_delete_tutorials_with_incorrect_auth_token
     # Create a dummy tutorial
     tutorial = FactoryBot.create(:tutorial)
 
-    auth_data_to_header = {
-      auth_token: 'incorrect_auth_token'
-    }
-
     # Add username and auth_token to Header
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(username: 'aadmin', auth_token: 'incorrect_auth_token')
 
      # Number of tutorials before DELETE
      number_of_tutorials = Tutorial.all.length
diff --git a/test/api/units/task_definitions_api_test.rb b/test/api/units/task_definitions_api_test.rb
index 88cac7470..2f2ab2b17 100644
--- a/test/api/units/task_definitions_api_test.rb
+++ b/test/api/units/task_definitions_api_test.rb
@@ -199,7 +199,7 @@ def test_submission_creates_folders
     task = project.task_for_task_definition(td)
 
     assert File.directory? FileHelper.student_work_dir(:new, task, false)
-    assert File.exists? File.join(FileHelper.student_work_dir(:new, task, false), '000-document.pdf')
+    assert File.exist? File.join(FileHelper.student_work_dir(:new, task, false), '000-document.pdf')
 
     task.destroy
 
@@ -247,7 +247,7 @@ def test_change_to_group_after_submissions
     assert task.convert_submission_to_pdf
     path = task.zip_file_path_for_done_task
     assert path
-    assert File.exists? path
+    assert File.exist? path
 
     # Change it to a group task
 
@@ -261,10 +261,10 @@ def test_change_to_group_after_submissions
     task.task_definition = td
     path = task.zip_file_path_for_done_task
     assert path
-    assert File.exists? path
+    assert File.exist? path
 
     td.destroy
-    assert_not File.exists? path
+    assert_not File.exist? path
   end
 
   def test_task_related_to_task_def
diff --git a/test/api/units_api_test.rb b/test/api/units_api_test.rb
index d1ee1b99d..bb9293a49 100644
--- a/test/api/units_api_test.rb
+++ b/test/api/units_api_test.rb
@@ -401,18 +401,15 @@ def test_fail_units_get_by_id
     assert_equal 404, last_response.status
   end
 
-  def test_put_update_unit_custom_token(token='abcdef')
+  def test_put_update_unit_custom_token()
     unit= Unit.first
+    token='abcdef'
     data_to_put = {
         unit: unit
     }
 
-    auth_data_to_header = {
-      auth_token: token
-    }
-
     # Add username and auth_token to Header
-    add_auth_header_for(auth_data_to_header)
+    add_auth_header_for(auth_token: token, username: 'aadmin')
 
     put_json '/api/units/1', data_to_put
     assert_equal 419, last_response.status
diff --git a/test/helpers/json_helper.rb b/test/helpers/json_helper.rb
index 383874ef6..555e83d74 100644
--- a/test/helpers/json_helper.rb
+++ b/test/helpers/json_helper.rb
@@ -12,14 +12,15 @@ module JsonHelper
     #
     def post_json(endpoint, data)
       header 'CONTENT_TYPE', 'application/json'
-      post URI.encode(endpoint), data.to_json
+
+      post URI::Parser.new.escape(endpoint), data.to_json
     end
 
     #
     # PUTs a hash data as JSON with content-type "application/json"
     #
     def put_json(endpoint, data)
-      put URI.encode(endpoint), data.to_json, 'CONTENT_TYPE' => 'application/json'
+      put URI::Parser.new.escape(endpoint), data.to_json, 'CONTENT_TYPE' => 'application/json'
     end
 
     #
@@ -27,7 +28,7 @@ def put_json(endpoint, data)
     #
     def delete_json(endpoint)
       header 'CONTENT_TYPE', 'application/json'
-      delete URI.encode(endpoint)
+      delete URI::Parser.new.escape(endpoint)
     end
 
     #
diff --git a/test/models/file_helper_test.rb b/test/models/file_helper_test.rb
index 73920123d..717149f35 100644
--- a/test/models/file_helper_test.rb
+++ b/test/models/file_helper_test.rb
@@ -7,7 +7,7 @@ def test_convert_use_with_gif
     Dir.mktmpdir do |dir|
       dest_file = "#{dir}#{File.basename(in_file, ".*")}.jpg"
       assert FileHelper.compress_image_to_dest(in_file, dest_file, true)
-      assert File.exists? dest_file
+      assert File.exist? dest_file
     end
   end
 end
diff --git a/test/models/task_test.rb b/test/models/task_test.rb
index c1f213f41..36387451c 100644
--- a/test/models/task_test.rb
+++ b/test/models/task_test.rb
@@ -76,11 +76,11 @@ def test_pdf_creation_with_gif
     assert task.convert_submission_to_pdf
     path = task.zip_file_path_for_done_task
     assert path
-    assert File.exists? path
-    assert File.exists? task.final_pdf_path
+    assert File.exist? path
+    assert File.exist? task.final_pdf_path
 
     td.destroy
-    assert_not File.exists? path
+    assert_not File.exist? path
   end
 
   def test_image_upload
@@ -120,7 +120,7 @@ def test_image_upload
     task = project.task_for_task_definition(td)
     task.move_files_to_in_process(FileHelper.student_work_dir(:new))
 
-    assert File.exists? "#{Doubtfire::Application.config.student_work_dir}/in_process/#{task.id}/000-image.jpg"
+    assert File.exist? "#{Doubtfire::Application.config.student_work_dir}/in_process/#{task.id}/000-image.jpg"
 
     td.destroy
   end
@@ -163,11 +163,11 @@ def test_pdf_creation_with_jpg
     assert task.convert_submission_to_pdf
     path = task.zip_file_path_for_done_task
     assert path
-    assert File.exists? path
-    assert File.exists? task.final_pdf_path
+    assert File.exist? path
+    assert File.exist? task.final_pdf_path
 
     td.destroy
-    assert_not File.exists? path
+    assert_not File.exist? path
   end
 
   def test_pdf_with_quotes_in_task_title
@@ -207,10 +207,10 @@ def test_pdf_with_quotes_in_task_title
     task.convert_submission_to_pdf
 
     path = task.final_pdf_path
-    assert File.exists? path
+    assert File.exist? path
 
     td.destroy
-    assert_not File.exists? path
+    assert_not File.exist? path
   end
 
   def test_copy_draft_learning_summary
@@ -247,10 +247,10 @@ def test_copy_draft_learning_summary
     project.reload
     assert project.uses_draft_learning_summary
     path = File.join(project.portfolio_temp_path, '000-document-LearningSummaryReport.pdf')
-    assert File.exists? path
+    assert File.exist? path
 
     unit.destroy
-    assert_not File.exists? path
+    assert_not File.exist? path
   end
 
   def test_draft_learning_summary_wont_copy
@@ -265,7 +265,7 @@ def test_draft_learning_summary_wont_copy
     FileUtils.mkdir_p(project.portfolio_temp_path)
 
     FileUtils.cp Rails.root.join('test_files/unit_files/sample-learning-summary.pdf'), path
-    assert File.exists? path
+    assert File.exist? path
 
     data_to_post = {
       trigger: 'ready_for_feedback'
@@ -289,6 +289,6 @@ def test_draft_learning_summary_wont_copy
     assert_not project.uses_draft_learning_summary
 
     unit.destroy
-    assert_not File.exists? path
+    assert_not File.exist? path
   end
 end
diff --git a/test/models/unit_model_test.rb b/test/models/unit_model_test.rb
index a4dccf8b5..51ab18458 100644
--- a/test/models/unit_model_test.rb
+++ b/test/models/unit_model_test.rb
@@ -25,10 +25,10 @@ class UnitModelTest < ActiveSupport::TestCase
     @unit.import_task_files_from_zip Rails.root.join('test_files',"#{@unit.code}-Tasks.zip")
 
     @unit.task_definitions.each do |td|
-      assert File.exists?(td.task_sheet), "#{td.abbreviation} task sheet missing"
+      assert File.exist?(td.task_sheet), "#{td.abbreviation} task sheet missing"
     end
 
-    assert File.exists? @unit.task_definitions.first.task_resources
+    assert File.exist? @unit.task_definitions.first.task_resources
   end
 
   test 'rollover of task files' do
@@ -38,10 +38,10 @@ class UnitModelTest < ActiveSupport::TestCase
     unit2 = @unit.rollover TeachingPeriod.find(2), nil, nil
 
     unit2.task_definitions.each do |td|
-      assert File.exists?(td.task_sheet), 'task sheet is absent'
+      assert File.exist?(td.task_sheet), 'task sheet is absent'
     end
 
-    assert File.exists?(unit2.task_definitions.first.task_resources), 'task resource is absent'
+    assert File.exist?(unit2.task_definitions.first.task_resources), 'task resource is absent'
 
     unit2.destroy
   end
@@ -596,12 +596,12 @@ def test_portfolio_zip
     unit.active_projects.each do |p|
       DatabasePopulator.generate_portfolio(p)
       assert p.has_portfolio
-      assert File.exists?(p.portfolio_path)
+      assert File.exist?(p.portfolio_path)
       paths << p.portfolio_path
     end
 
     filename = unit.get_portfolio_zip(unit.main_convenor_user)
-    assert File.exists? filename
+    assert File.exist? filename
     Zip::File.open(filename) do |zip_file|
       assert_equal unit.active_projects.count, zip_file.count
     end
@@ -610,7 +610,7 @@ def test_portfolio_zip
     unit.destroy!
 
     paths.each do |path|
-      refute File.exists?(path)
+      refute File.exist?(path)
     end
   end