diff --git a/Gemfile b/Gemfile
index 4bdc5e8d..6ca05b58 100644
--- a/Gemfile
+++ b/Gemfile
@@ -72,6 +72,7 @@ group :test do
   gem 'database_cleaner'
   gem 'nyan-cat-formatter'
   gem 'rspec-autotest'
+  gem 'rspec-collection_matchers'
   gem 'rspec-rails'
   gem 'shoulda-matchers'
   gem 'simplecov', require: false
diff --git a/Gemfile.lock b/Gemfile.lock
index e3afa6a6..8ba86613 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -318,6 +318,8 @@ GEM
       rspec-mocks (~> 3.9.0)
     rspec-autotest (1.0.2)
       rspec-core (>= 2.99.0.beta1, < 4.0.0)
+    rspec-collection_matchers (1.1.3)
+      rspec-expectations (>= 2.99.0.beta1)
     rspec-core (3.9.0)
       rspec-support (~> 3.9.0)
     rspec-expectations (3.9.0)
@@ -486,6 +488,7 @@ DEPENDENCIES
   ransack
   rest-client
   rspec-autotest
+  rspec-collection_matchers
   rspec-rails
   rubocop
   rubocop-rspec
diff --git a/app/services/exercise_service/check_external.rb b/app/services/exercise_service/check_external.rb
index 1aac945b..a7add85d 100644
--- a/app/services/exercise_service/check_external.rb
+++ b/app/services/exercise_service/check_external.rb
@@ -16,8 +16,8 @@ module ExerciseService
       response_hash = JSON.parse(response.body, symbolize_names: true)
 
       {error: false}.merge(response_hash.slice(:message, :exercise_found, :update_right))
-    rescue Faraday::Error => e
-      {error: true, message: I18n.t('exercises.export_codeharbor.error', message: e.message)}
+    rescue Faraday::Error, JSON::ParserError
+      {error: true, message: I18n.t('exercises.export_codeharbor.error')}
     end
 
     private
diff --git a/app/services/exercise_service/push_external.rb b/app/services/exercise_service/push_external.rb
index 93dacb81..3410a7ba 100644
--- a/app/services/exercise_service/push_external.rb
+++ b/app/services/exercise_service/push_external.rb
@@ -17,9 +17,9 @@ module ExerciseService
           request.body = body
         end
 
-        return response.success? ? nil : response.body
+        response.success? ? nil : response.body
       rescue StandardError => e
-        return e.message
+        e.message
       end
     end
 
diff --git a/app/services/proforma_service/convert_exercise_to_task.rb b/app/services/proforma_service/convert_exercise_to_task.rb
index e22aa709..7a44c5aa 100644
--- a/app/services/proforma_service/convert_exercise_to_task.rb
+++ b/app/services/proforma_service/convert_exercise_to_task.rb
@@ -22,11 +22,9 @@ module ProformaService
           title: @exercise.title,
           description: @exercise.description,
           internal_description: @exercise.instructions,
-          # proglang: proglang,
           files: task_files,
           tests: tests,
           uuid: uuid,
-          # parent_uuid: parent_uuid,
           language: DEFAULT_LANGUAGE,
           model_solutions: model_solutions,
           import_checksum: @exercise.import_checksum
@@ -66,8 +64,6 @@ module ProformaService
           files: test_file(file),
           meta_data: {
             'feedback-message' => file.feedback_message
-            # 'testing-framework' => test.testing_framework&.name,
-            # 'testing-framework-version' => test.testing_framework&.version
           }.compact
         )
       end
diff --git a/app/services/proforma_service/convert_task_to_exercise.rb b/app/services/proforma_service/convert_task_to_exercise.rb
index 0264494f..f87a9354 100644
--- a/app/services/proforma_service/convert_task_to_exercise.rb
+++ b/app/services/proforma_service/convert_task_to_exercise.rb
@@ -22,7 +22,6 @@ module ProformaService
         description: @task.description,
         instructions: @task.internal_description,
         files: files,
-        uuid: @task.uuid,
         import_checksum: @task.checksum
       )
     end
@@ -56,10 +55,10 @@ module ProformaService
         name: File.basename(file.filename, '.*'),
         read_only: file.usage_by_lms != 'edit',
         role: file.internal_description,
-        path: File.dirname(file.filename)
+        path: File.dirname(file.filename).in?(['.', '']) ? nil : File.dirname(file.filename)
       }.tap do |params|
         if file.binary
-          params[:native_file] = FileIO.new(file.content.force_encoding('UTF-8'), File.basename(file.filename))
+          params[:native_file] = FileIO.new(file.content.dup.force_encoding('UTF-8'), File.basename(file.filename))
         else
           params[:content] = file.content
         end
diff --git a/app/services/proforma_service/import.rb b/app/services/proforma_service/import.rb
index b8ec628b..4fa0676e 100644
--- a/app/services/proforma_service/import.rb
+++ b/app/services/proforma_service/import.rb
@@ -12,7 +12,7 @@ module ProformaService
         importer = Proforma::Importer.new(@zip)
         @task = importer.perform
 
-        exercise = Exercise.find_by(uuid: @task.uuid)
+        exercise = base_exercise
         exercise_files = exercise&.files&.to_a
 
         exercise = ConvertTaskToExercise.call(task: @task, user: @user, exercise: exercise)
@@ -26,6 +26,17 @@ module ProformaService
 
     private
 
+    def base_exercise
+      exercise = Exercise.find_by(uuid: @task.uuid)
+      if exercise
+        return exercise if ExercisePolicy.new(@user, exercise).update?
+
+        return Exercise.new(uuid: SecureRandom.uuid, unpublished: true)
+      end
+
+      Exercise.new(uuid: @task.uuid || SecureRandom.uuid, unpublished: true)
+    end
+
     def import_multi
       Zip::File.open(@zip.path) do |zip_file|
         zip_files = zip_file.filter { |entry| entry.name.match?(/\.zip$/) }
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 8a0707e1..6211c3e1 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -329,7 +329,7 @@ en:
       dialogtitle: Export to Codeharbor
       successfully_exported: 'Exercise has been successfully exported.<br>ID: %{id}<br>Title: %{title}'
       export_failed: 'Export has failed.<br>ID: %{id}<br>Title: %{title}<br><br>Error: %{error}'
-      error: 'An error occurred while contacting Codeharbor<br>Error: %{message}'
+      error: 'An error occurred while contacting Codeharbor'
       checking_codeharbor: Checking if the exercise exists on Codeharbor.
       buttons:
         retry: Retry
diff --git a/spec/factories/code_ocean/file.rb b/spec/factories/code_ocean/file.rb
index 186ad1d1..64245e97 100644
--- a/spec/factories/code_ocean/file.rb
+++ b/spec/factories/code_ocean/file.rb
@@ -10,6 +10,24 @@ module CodeOcean
       name { SecureRandom.hex }
       read_only { false }
       role { 'main_file' }
+
+      trait(:image) do
+        association :file_type, factory: :dot_png
+        name { 'poster' }
+        native_file { Rack::Test::UploadedFile.new(Rails.root.join('db', 'seeds', 'audio_video', 'poster.png'), 'image/png') }
+      end
+    end
+
+    factory :test_file, class: CodeOcean::File do
+      content { '' }
+      association :context, factory: :dummy
+      association :file_type, factory: :dot_rb
+      hidden { true }
+      name { SecureRandom.hex }
+      read_only { true }
+      role { 'teacher_defined_test' }
+      feedback_message { 'feedback_message' }
+      weight { 1 }
     end
   end
 end
diff --git a/spec/services/exercise_service/check_external_spec.rb b/spec/services/exercise_service/check_external_spec.rb
new file mode 100644
index 00000000..ea7874c6
--- /dev/null
+++ b/spec/services/exercise_service/check_external_spec.rb
@@ -0,0 +1,76 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe ExerciseService::CheckExternal do
+  describe '.new' do
+    subject(:export_service) { described_class.new(uuid: uuid, codeharbor_link: codeharbor_link) }
+
+    let(:uuid) { SecureRandom.uuid }
+    let(:codeharbor_link) { FactoryBot.build(:codeharbor_link) }
+
+    it 'assigns uuid' do
+      expect(export_service.instance_variable_get(:@uuid)).to be uuid
+    end
+
+    it 'assigns codeharbor_link' do
+      expect(export_service.instance_variable_get(:@codeharbor_link)).to be codeharbor_link
+    end
+  end
+
+  describe '#execute' do
+    subject(:check_external_service) { described_class.call(uuid: uuid, codeharbor_link: codeharbor_link) }
+
+    let(:uuid) { SecureRandom.uuid }
+    let(:codeharbor_link) { FactoryBot.build(:codeharbor_link) }
+    let(:response) { {}.to_json }
+
+    before { stub_request(:post, codeharbor_link.check_uuid_url).to_return(body: response) }
+
+    it 'calls the correct url' do
+      expect(check_external_service).to have_requested(:post, codeharbor_link.check_uuid_url)
+    end
+
+    it 'submits the correct headers' do
+      expect(check_external_service).to have_requested(:post, codeharbor_link.check_uuid_url)
+        .with(headers: {content_type: 'application/json', authorization: "Bearer #{codeharbor_link.api_key}"})
+    end
+
+    it 'submits the correct body' do
+      expect(check_external_service).to have_requested(:post, codeharbor_link.check_uuid_url)
+        .with(body: {uuid: uuid}.to_json)
+    end
+
+    context 'when response contains a JSON with expected keys' do
+      let(:response) { {message: 'message', exercise_found: true, update_right: true}.to_json }
+
+      it 'returns the correct hash' do
+        expect(check_external_service).to eql(error: false, message: 'message', exercise_found: true, update_right: true)
+      end
+
+      context 'with different values' do
+        let(:response) { {message: 'message', exercise_found: false, update_right: false}.to_json }
+
+        it 'returns the correct hash' do
+          expect(check_external_service).to eql(error: false, message: 'message', exercise_found: false, update_right: false)
+        end
+      end
+    end
+
+    context 'when response does not contain JSON' do
+      let(:response) { 'foo' }
+
+      it 'returns the correct hash' do
+        expect(check_external_service).to eql(error: true, message: I18n.t('exercises.export_codeharbor.error'))
+      end
+    end
+
+    context 'when the request fails' do
+      before { allow(Faraday).to receive(:new).and_raise(Faraday::Error, 'error') }
+
+      it 'returns the correct hash' do
+        expect(check_external_service).to eql(error: true, message: I18n.t('exercises.export_codeharbor.error'))
+      end
+    end
+  end
+end
diff --git a/spec/services/exercise_service/push_external_spec.rb b/spec/services/exercise_service/push_external_spec.rb
new file mode 100644
index 00000000..20c07a0a
--- /dev/null
+++ b/spec/services/exercise_service/push_external_spec.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ExerciseService::PushExternal do
+  describe '.new' do
+    subject(:push_external) { described_class.new(zip: zip, codeharbor_link: codeharbor_link) }
+
+    let(:zip) { ProformaService::ExportTask.call(exercise: FactoryBot.build(:dummy)) }
+    let(:codeharbor_link) { FactoryBot.build(:codeharbor_link) }
+
+    it 'assigns zip' do
+      expect(push_external.instance_variable_get(:@zip)).to be zip
+    end
+
+    it 'assigns codeharbor_link' do
+      expect(push_external.instance_variable_get(:@codeharbor_link)).to be codeharbor_link
+    end
+  end
+
+  describe '#execute' do
+    subject(:push_external) { described_class.call(zip: zip, codeharbor_link: codeharbor_link) }
+
+    let(:zip) { ProformaService::ExportTask.call(exercise: FactoryBot.build(:dummy)) }
+    let(:codeharbor_link) { FactoryBot.build(:codeharbor_link) }
+    let(:status) { 200 }
+    let(:response) { '' }
+
+    before { stub_request(:post, codeharbor_link.push_url).to_return(status: status, body: response) }
+
+    it 'calls the correct url' do
+      expect(push_external).to have_requested(:post, codeharbor_link.push_url)
+    end
+
+    it 'submits the correct headers' do
+      expect(push_external).to have_requested(:post, codeharbor_link.push_url)
+        .with(headers: {content_type: 'application/zip',
+                        authorization: "Bearer #{codeharbor_link.api_key}",
+                        content_length: zip.string.length})
+    end
+
+    it 'submits the correct body' do
+      expect(push_external).to have_requested(:post, codeharbor_link.push_url)
+        .with(body: zip.string)
+    end
+
+    context 'when response status is success' do
+      it { is_expected.to be nil }
+
+      context 'when response status is 500' do
+        let(:status) { 500 }
+        let(:response) { 'an error occured' }
+
+        it { is_expected.to be response }
+      end
+    end
+
+    context 'when an error occurs' do
+      before { allow(Faraday).to receive(:new).and_raise(StandardError) }
+
+      it { is_expected.not_to be nil }
+    end
+  end
+end
diff --git a/spec/services/proforma_service/convert_exercise_to_task_spec.rb b/spec/services/proforma_service/convert_exercise_to_task_spec.rb
new file mode 100644
index 00000000..ae2976d1
--- /dev/null
+++ b/spec/services/proforma_service/convert_exercise_to_task_spec.rb
@@ -0,0 +1,198 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ProformaService::ConvertExerciseToTask do
+  describe '.new' do
+    subject(:convert_to_task) { described_class.new(exercise: exercise) }
+
+    let(:exercise) { FactoryBot.build(:dummy) }
+
+    it 'assigns exercise' do
+      expect(convert_to_task.instance_variable_get(:@exercise)).to be exercise
+    end
+  end
+
+  describe '#execute' do
+    subject(:task) { convert_to_task.execute }
+
+    let(:convert_to_task) { described_class.new(exercise: exercise) }
+    let(:exercise) do
+      FactoryBot.create(:dummy,
+                        instructions: 'instruction',
+                        uuid: SecureRandom.uuid,
+                        files: files + tests)
+    end
+    let(:files) { [] }
+    let(:tests) { [] }
+
+    it 'creates a task with all basic attributes' do
+      expect(task).to have_attributes(
+        title: exercise.title,
+        description: exercise.description,
+        internal_description: exercise.instructions,
+        # proglang: {
+        #   name: exercise.execution_environment.language,
+        #   version: exercise.execution_environment.version
+        # },
+        uuid: exercise.uuid,
+        language: described_class::DEFAULT_LANGUAGE,
+        # parent_uuid: exercise.clone_relations.first&.origin&.uuid,
+        files: [],
+        tests: [],
+        model_solutions: [],
+        import_checksum: exercise.import_checksum
+      )
+    end
+
+    context 'when exercise has a mainfile' do
+      let(:files) { [file] }
+      let(:file) { FactoryBot.build(:file) }
+
+      it 'creates a task-file with the correct attributes' do
+        expect(task.files.first).to have_attributes(
+          id: file.id,
+          content: file.content,
+          filename: file.name_with_extension,
+          used_by_grader: true,
+          usage_by_lms: 'edit',
+          visible: 'yes',
+          binary: false,
+          internal_description: 'main_file'
+        )
+      end
+    end
+
+    context 'when exercise has a regular file' do
+      let(:files) { [file] }
+      let(:file) { FactoryBot.build(:file, role: 'regular_file', hidden: hidden, read_only: read_only) }
+      let(:hidden) { true }
+      let(:read_only) { true }
+
+      it 'creates a task-file with the correct attributes' do
+        expect(task.files.first).to have_attributes(
+          id: file.id,
+          content: file.content,
+          filename: file.name_with_extension,
+          used_by_grader: true,
+          usage_by_lms: 'display',
+          visible: 'no',
+          binary: false,
+          internal_description: 'regular_file'
+        )
+      end
+
+      context 'when file is not hidden' do
+        let(:hidden) { false }
+
+        it 'creates a task-file with the correct attributes' do
+          expect(task.files.first).to have_attributes(visible: 'yes')
+        end
+      end
+
+      context 'when file is not read_only' do
+        let(:read_only) { false }
+
+        it 'creates a task-file with the correct attributes' do
+          expect(task.files.first).to have_attributes(usage_by_lms: 'edit')
+        end
+      end
+
+      context 'when file has an attachment' do
+        let(:file) { FactoryBot.build(:file, :image, role: 'regular_file') }
+
+        it 'creates a task-file with the correct attributes' do
+          expect(task.files.first).to have_attributes(
+            used_by_grader: false,
+            binary: true,
+            mimetype: 'image/png'
+          )
+        end
+      end
+    end
+
+    context 'when exercise has a file with role reference implementation' do
+      let(:files) { [file] }
+      let(:file) { FactoryBot.build(:file, role: 'reference_implementation') }
+
+      it 'creates a task with one model-solution' do
+        expect(task.model_solutions).to have(1).item
+      end
+
+      it 'creates a model-solution with one file' do
+        expect(task.model_solutions.first).to have_attributes(
+          id: "ms-#{file.id}",
+          files: have(1).item
+        )
+      end
+
+      it 'creates a model-solution with one file with correct attributes' do
+        expect(task.model_solutions.first.files.first).to have_attributes(
+          id: file.id,
+          content: file.content,
+          filename: file.name_with_extension,
+          used_by_grader: false,
+          usage_by_lms: 'display',
+          visible: 'delayed',
+          binary: false,
+          internal_description: 'reference_implementation'
+        )
+      end
+    end
+
+    context 'when exercise has multiple files with role reference implementation' do
+      let(:files) { FactoryBot.build_list(:file, 2, role: 'reference_implementation') }
+
+      it 'creates a task with two model-solutions' do
+        expect(task.model_solutions).to have(2).items
+      end
+    end
+
+    context 'when exercise has a test' do
+      let(:tests) { [test_file] }
+      let(:test_file) { FactoryBot.build(:test_file) }
+      # let(:file) { FactoryBot.build(:codeharbor_test_file) }
+
+      it 'creates a task with one test' do
+        expect(task.tests).to have(1).item
+      end
+
+      it 'creates a test with one file' do
+        expect(task.tests.first).to have_attributes(
+          id: test_file.id,
+          title: test_file.name,
+          files: have(1).item,
+          meta_data: {'feedback-message' => test_file.feedback_message}
+        )
+      end
+
+      it 'creates a test with one file with correct attributes' do
+        expect(task.tests.first.files.first).to have_attributes(
+          id: test_file.id,
+          content: test_file.content,
+          filename: test_file.name_with_extension,
+          used_by_grader: true,
+          visible: 'no',
+          binary: false,
+          internal_description: 'teacher_defined_test'
+        )
+      end
+
+      context 'when exercise_file is not hidden' do
+        let(:test_file) { FactoryBot.create(:test_file, hidden: false) }
+
+        it 'creates the test file with the correct attribute' do
+          expect(task.tests.first.files.first).to have_attributes(visible: 'yes')
+        end
+      end
+    end
+
+    context 'when exercise has multiple tests' do
+      let(:tests) { FactoryBot.build_list(:test_file, 2) }
+
+      it 'creates a task with two tests' do
+        expect(task.tests).to have(2).items
+      end
+    end
+  end
+end
diff --git a/spec/services/proforma_service/convert_task_to_exercise_spec.rb b/spec/services/proforma_service/convert_task_to_exercise_spec.rb
new file mode 100644
index 00000000..4f0a3b8c
--- /dev/null
+++ b/spec/services/proforma_service/convert_task_to_exercise_spec.rb
@@ -0,0 +1,377 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe ProformaService::ConvertTaskToExercise do
+  describe '.new' do
+    subject(:convert_to_exercise_service) { described_class.new(task: task, user: user, exercise: exercise) }
+
+    let(:task) { Proforma::Task.new }
+    let(:user) { FactoryBot.build(:teacher) }
+    let(:exercise) { FactoryBot.build(:dummy) }
+
+    it 'assigns task' do
+      expect(convert_to_exercise_service.instance_variable_get(:@task)).to be task
+    end
+
+    it 'assigns user' do
+      expect(convert_to_exercise_service.instance_variable_get(:@user)).to be user
+    end
+
+    it 'assigns exercise' do
+      expect(convert_to_exercise_service.instance_variable_get(:@exercise)).to be exercise
+    end
+  end
+
+  describe '#execute' do
+    subject(:convert_to_exercise_service) { described_class.call(task: task, user: user, exercise: exercise) }
+
+    before { FactoryBot.create(:dot_txt) }
+
+    let(:task) do
+      Proforma::Task.new(
+        title: 'title',
+        description: 'description',
+        internal_description: 'internal_description',
+        proglang: {name: 'proglang-name', version: 'proglang-version'},
+        uuid: 'uuid',
+        parent_uuid: 'parent_uuid',
+        language: 'language',
+        model_solutions: model_solutions,
+        files: files,
+        tests: tests,
+        import_checksum: 'import_checksum',
+        checksum: 'checksum'
+      )
+    end
+    let(:user) { FactoryBot.create(:teacher) }
+    let(:files) { [] }
+    let(:tests) { [] }
+    let(:model_solutions) { [] }
+    let(:exercise) {}
+
+    it 'creates an exercise with the correct attributes' do
+      expect(convert_to_exercise_service).to have_attributes(
+        title: 'title',
+        description: 'description',
+        instructions: 'internal_description',
+        execution_environment: be_blank,
+        uuid: be_blank,
+        unpublished: true,
+        user: user,
+        files: be_empty
+      )
+    end
+
+    context 'when task has a file' do
+      let(:files) { [file] }
+      let(:file) do
+        Proforma::TaskFile.new(
+          id: 'id',
+          content: content,
+          filename: 'filename.txt',
+          used_by_grader: 'used_by_grader',
+          visible: 'yes',
+          usage_by_lms: usage_by_lms,
+          binary: binary,
+          internal_description: 'regular_file',
+          mimetype: mimetype
+        )
+      end
+      let(:usage_by_lms) { 'display' }
+      let(:mimetype) { 'mimetype' }
+      let(:binary) { false }
+      let(:content) { 'content' }
+
+      it 'creates an exercise with a file that has the correct attributes' do
+        expect(convert_to_exercise_service.files.first).to have_attributes(
+          content: 'content',
+          name: 'filename',
+          role: 'regular_file',
+          hidden: false,
+          read_only: true,
+          file_type: be_a(FileType).and(have_attributes(file_extension: '.txt'))
+        )
+      end
+
+      it 'creates a new Exercise on save' do
+        expect { convert_to_exercise_service.save! }.to change(Exercise, :count).by(1)
+      end
+
+      context 'when file is very large' do
+        let(:content) { 'test' * 10**5 }
+
+        it 'creates an exercise with a file that has the correct attributes' do
+          expect(convert_to_exercise_service.files.first).to have_attributes(content: content)
+        end
+      end
+
+      context 'when file is binary' do
+        let(:mimetype) { 'image/png' }
+        let(:binary) { true }
+
+        it 'creates an exercise with a file with attachment and the correct attributes' do
+          expect(convert_to_exercise_service.files.first.native_file).to be_present
+        end
+      end
+
+      context 'when usage_by_lms is edit' do
+        let(:usage_by_lms) { 'edit' }
+
+        it 'creates an exercise with a file with correct attributes' do
+          expect(convert_to_exercise_service.files.first).to have_attributes(read_only: false)
+        end
+      end
+
+      context 'when file is a model-solution-placeholder (needed by proforma until issue #5 is resolved)' do
+        let(:file) { Proforma::TaskFile.new(id: 'ms-placeholder-file') }
+
+        it 'leaves exercise_files empty' do
+          expect(convert_to_exercise_service.files).to be_empty
+        end
+      end
+    end
+
+    context 'when task has a model-solution' do
+      let(:model_solutions) { [model_solution] }
+      let(:model_solution) do
+        Proforma::ModelSolution.new(
+          id: 'ms-id',
+          files: ms_files
+        )
+      end
+      let(:ms_files) { [ms_file] }
+      let(:ms_file) do
+        Proforma::TaskFile.new(
+          id: 'ms-file',
+          content: 'content',
+          filename: 'filename.txt',
+          used_by_grader: 'used_by_grader',
+          visible: 'yes',
+          usage_by_lms: 'display',
+          binary: false,
+          internal_description: 'reference_implementation'
+        )
+      end
+
+      it 'creates an exercise with a file with role Reference Implementation' do
+        expect(convert_to_exercise_service.files.first).to have_attributes(
+          role: 'reference_implementation'
+        )
+      end
+
+      context 'when task has two model-solutions' do
+        let(:model_solutions) { [model_solution, model_solution2] }
+        let(:model_solution2) do
+          Proforma::ModelSolution.new(
+            id: 'ms-id-2',
+            files: ms_files_2
+          )
+        end
+        let(:ms_files_2) { [ms_file_2] }
+        let(:ms_file_2) do
+          Proforma::TaskFile.new(
+            id: 'ms-file-2',
+            content: 'content',
+            filename: 'filename.txt',
+            used_by_grader: 'used_by_grader',
+            visible: 'yes',
+            usage_by_lms: 'display',
+            binary: false,
+            internal_description: 'reference_implementation'
+          )
+        end
+
+        it 'creates an exercise with two files with role Reference Implementation' do
+          expect(convert_to_exercise_service.files).to have(2).items.and(all(have_attributes(role: 'reference_implementation')))
+        end
+      end
+    end
+
+    context 'when task has a test' do
+      let(:tests) { [test] }
+      let(:test) do
+        Proforma::Test.new(
+          id: 'test-id',
+          title: 'title',
+          description: 'description',
+          internal_description: 'internal_description',
+          test_type: 'test_type',
+          files: test_files,
+          meta_data: {
+            'feedback-message' => 'feedback-message',
+            'testing-framework' => 'testing-framework',
+            'testing-framework-version' => 'testing-framework-version'
+          }
+        )
+      end
+
+      let(:test_files) { [test_file] }
+      let(:test_file) do
+        Proforma::TaskFile.new(
+          id: 'test_file_id',
+          content: 'testfile-content',
+          filename: 'testfile.txt',
+          used_by_grader: 'yes',
+          visible: 'no',
+          usage_by_lms: 'display',
+          binary: false,
+          internal_description: 'teacher_defined_test'
+        )
+      end
+
+      it 'creates an exercise with a test' do
+        expect(convert_to_exercise_service.files.select { |file| file.role == 'teacher_defined_test' }).to have(1).item
+      end
+
+      it 'creates an exercise with a test with correct attributes' do
+        expect(convert_to_exercise_service.files.select { |file| file.role == 'teacher_defined_test' }.first).to have_attributes(
+          feedback_message: 'feedback-message',
+          content: 'testfile-content',
+          name: 'testfile',
+          role: 'teacher_defined_test',
+          hidden: true,
+          read_only: true,
+          file_type: be_a(FileType).and(have_attributes(file_extension: '.txt'))
+        )
+      end
+
+      context 'when task has multiple tests' do
+        let(:tests) { [test, test2] }
+        let(:test2) do
+          Proforma::Test.new(
+            files: test_files2,
+            meta_data: {
+              'feedback-message' => 'feedback-message',
+              'testing-framework' => 'testing-framework',
+              'testing-framework-version' => 'testing-framework-version'
+            }
+          )
+        end
+        let(:test_files2) { [test_file2] }
+        let(:test_file2) do
+          Proforma::TaskFile.new(
+            id: 'test_file_id2',
+            content: 'testfile-content',
+            filename: 'testfile.txt',
+            used_by_grader: 'yes',
+            visible: 'no',
+            usage_by_lms: 'display',
+            binary: false,
+            internal_description: 'teacher_defined_test'
+          )
+        end
+
+        it 'creates an exercise with two test' do
+          expect(convert_to_exercise_service.files.select { |file| file.role == 'teacher_defined_test' }).to have(2).items
+        end
+      end
+    end
+
+    context 'when exercise is set' do
+      let(:exercise) do
+        FactoryBot.create(
+          :files,
+          title: 'exercise-title',
+          description: 'exercise-description',
+          instructions: 'exercise-instruction'
+        )
+      end
+
+      before { exercise.reload }
+
+      it 'assigns all values to given exercise' do
+        convert_to_exercise_service.save
+        expect(exercise.reload).to have_attributes(
+          id: exercise.id,
+          title: task.title,
+          description: task.description,
+          instructions: task.internal_description,
+          execution_environment: exercise.execution_environment,
+          uuid: exercise.uuid,
+          user: exercise.user,
+          files: be_empty
+        )
+      end
+
+      it 'does not create a new Exercise on save' do
+        expect { convert_to_exercise_service.save }.not_to change(Exercise, :count)
+      end
+
+      context 'with file, model solution and test' do
+        let(:files) { [file] }
+        let(:file) do
+          Proforma::TaskFile.new(
+            id: 'id',
+            content: 'content',
+            filename: 'filename.txt',
+            used_by_grader: 'used_by_grader',
+            visible: 'yes',
+            usage_by_lms: 'display',
+            binary: false,
+            internal_description: 'regular_file'
+          )
+        end
+        let(:tests) { [test] }
+        let(:test) do
+          Proforma::Test.new(
+            id: 'test-id',
+            title: 'title',
+            description: 'description',
+            internal_description: 'regular_file',
+            test_type: 'test_type',
+            files: test_files,
+            meta_data: {
+              'feedback-message' => 'feedback-message',
+              'testing-framework' => 'testing-framework',
+              'testing-framework-version' => 'testing-framework-version'
+            }
+          )
+        end
+        let(:test_files) { [test_file] }
+        let(:test_file) do
+          Proforma::TaskFile.new(
+            id: 'test_file_id',
+            content: 'testfile-content',
+            filename: 'testfile.txt',
+            used_by_grader: 'yes',
+            visible: 'no',
+            usage_by_lms: 'display',
+            binary: false,
+            internal_description: 'teacher_defined_test'
+          )
+        end
+        let(:model_solutions) { [model_solution] }
+        let(:model_solution) do
+          Proforma::ModelSolution.new(
+            id: 'ms-id',
+            files: ms_files
+          )
+        end
+        let(:ms_files) { [ms_file] }
+        let(:ms_file) do
+          Proforma::TaskFile.new(
+            id: 'ms-file',
+            content: 'ms-content',
+            filename: 'filename.txt',
+            used_by_grader: 'used_by_grader',
+            visible: 'yes',
+            usage_by_lms: 'display',
+            binary: false,
+            internal_description: 'reference_implementation'
+          )
+        end
+
+        it 'assigns all values to given exercise' do
+          expect(convert_to_exercise_service).to have_attributes(
+            id: exercise.id,
+            files: have(3).items
+              .and(include(have_attributes(content: 'ms-content', role: 'reference_implementation')))
+              .and(include(have_attributes(content: 'content', role: 'regular_file')))
+              .and(include(have_attributes(content: 'testfile-content', role: 'teacher_defined_test')))
+          )
+        end
+      end
+    end
+  end
+end
diff --git a/spec/services/proforma_service/export_task_spec.rb b/spec/services/proforma_service/export_task_spec.rb
new file mode 100644
index 00000000..157094de
--- /dev/null
+++ b/spec/services/proforma_service/export_task_spec.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe ProformaService::ExportTask do
+  describe '.new' do
+    subject(:export_task) { described_class.new(exercise: exercise) }
+
+    let(:exercise) { FactoryBot.build(:dummy) }
+
+    it 'assigns exercise' do
+      expect(export_task.instance_variable_get(:@exercise)).to be exercise
+    end
+
+    context 'without exercise' do
+      subject(:export_task) { described_class.new }
+
+      it 'assigns exercise' do
+        expect(export_task.instance_variable_get(:@exercise)).to be nil
+      end
+    end
+  end
+
+  describe '#execute' do
+    subject(:export_task) { described_class.call(exercise: exercise) }
+
+    let(:task) { Proforma::Task.new }
+    let(:exercise) { FactoryBot.build(:dummy) }
+    let(:exporter) { instance_double('Proforma::Exporter', perform: 'zip') }
+
+    before do
+      allow(ProformaService::ConvertExerciseToTask).to receive(:call).with(exercise: exercise).and_return(task)
+      allow(Proforma::Exporter).to receive(:new).with(task).and_return(exporter)
+    end
+
+    it do
+      export_task
+      expect(exporter).to have_received(:perform)
+    end
+  end
+end
diff --git a/spec/services/proforma_service/import_spec.rb b/spec/services/proforma_service/import_spec.rb
new file mode 100644
index 00000000..118284f1
--- /dev/null
+++ b/spec/services/proforma_service/import_spec.rb
@@ -0,0 +1,190 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe ProformaService::Import do
+  describe '.new' do
+    subject(:import_service) { described_class.new(zip: zip, user: user) }
+
+    let(:zip) { Tempfile.new('proforma_test_zip_file') }
+    let(:user) { FactoryBot.build(:teacher) }
+
+    it 'assigns zip' do
+      expect(import_service.instance_variable_get(:@zip)).to be zip
+    end
+
+    it 'assigns user' do
+      expect(import_service.instance_variable_get(:@user)).to be user
+    end
+  end
+
+  describe '#execute' do
+    subject(:import_service) { described_class.call(zip: zip_file, user: import_user) }
+
+    let(:user) { FactoryBot.create(:teacher) }
+    let(:import_user) { user }
+    let(:zip_file) { Tempfile.new('proforma_test_zip_file') }
+    let(:exercise) do
+      FactoryBot.create(:dummy,
+                        instructions: 'instruction',
+                        execution_environment: execution_environment,
+                        files: files + tests,
+                        uuid: uuid,
+                        user: user)
+    end
+
+    let(:uuid) {}
+    let(:execution_environment) { FactoryBot.build(:java) }
+    let(:files) { [] }
+    let(:tests) { [] }
+    let(:exporter) { ProformaService::ExportTask.call(exercise: exercise.reload).string }
+
+    before do
+      zip_file.write(exporter)
+      zip_file.rewind
+    end
+
+    it { is_expected.to be_an_equal_exercise_as exercise }
+
+    it 'sets the correct user as owner of the exercise' do
+      expect(import_service.user).to be user
+    end
+
+    it 'sets the uuid' do
+      expect(import_service.uuid).not_to be_blank
+    end
+
+    context 'when no exercise exists' do
+      before { exercise.destroy }
+
+      it { is_expected.to be_valid }
+
+      it 'sets the correct user as owner of the exercise' do
+        expect(import_service.user).to be user
+      end
+
+      it 'sets the uuid' do
+        expect(import_service.uuid).not_to be_blank
+      end
+
+      context 'when task has a uuid' do
+        let(:uuid) { SecureRandom.uuid }
+
+        it 'sets the uuid' do
+          expect(import_service.uuid).to eql uuid
+        end
+      end
+    end
+
+    context 'when exercise has a mainfile' do
+      let(:files) { [file] }
+      let(:file) { FactoryBot.build(:file) }
+
+      it { is_expected.to be_an_equal_exercise_as exercise }
+
+      context 'when the mainfile is very large' do
+        let(:file) { FactoryBot.build(:file, content: 'test' * 10**5) }
+
+        it { is_expected.to be_an_equal_exercise_as exercise }
+      end
+    end
+
+    context 'when exercise has a regular file' do
+      let(:files) { [file] }
+      let(:file) { FactoryBot.build(:file, role: 'regular_file') }
+
+      it { is_expected.to be_an_equal_exercise_as exercise }
+
+      context 'when file has an attachment' do
+        let(:file) { FactoryBot.build(:file, :image, role: 'regular_file') }
+
+        it { is_expected.to be_an_equal_exercise_as exercise }
+      end
+    end
+
+    context 'when exercise has a file with role reference implementation' do
+      let(:files) { [file] }
+      let(:file) { FactoryBot.build(:file, role: 'reference_implementation', read_only: true) }
+
+      it { is_expected.to be_an_equal_exercise_as exercise }
+    end
+
+    context 'when exercise has multiple files with role reference implementation' do
+      let(:files) { FactoryBot.build_list(:file, 2, role: 'reference_implementation', read_only: true) }
+
+      it { is_expected.to be_an_equal_exercise_as exercise }
+    end
+
+    context 'when exercise has a test' do
+      let(:tests) { [test] }
+      let(:test) { FactoryBot.build(:test_file) }
+
+      it { is_expected.to be_an_equal_exercise_as exercise }
+    end
+
+    context 'when exercise has multiple tests' do
+      let(:tests) { FactoryBot.build_list(:test_file, 2) }
+
+      it { is_expected.to be_an_equal_exercise_as exercise }
+    end
+
+    # context 'when zip contains multiple tasks' do
+    #   let(:exporter) { ProformaService::ExportTasks.call(exercises: [exercise, exercise2]).string }
+
+    #   let(:exercise2) do
+    #     FactoryBot.create(:dummy,
+    #                       instruction: 'instruction2',
+    #                       execution_environment: execution_environment,
+    #                       exercise_files: [],
+    #                       tests: [],
+    #                       user: user)
+    #   end
+
+    #   it 'imports the exercises from zip containing multiple zips' do
+    #     expect(import_service).to all be_an(Exercise)
+    #   end
+
+    #   it 'imports the zip exactly how they were exported' do
+    #     expect(import_service).to all be_an_equal_exercise_as(exercise).or be_an_equal_exercise_as(exercise2)
+    #   end
+
+    #   context 'when a exercise has files and tests' do
+    #     let(:files) { [FactoryBot.build(:file), FactoryBot.build(:file, role: 'regular_file')] }
+    #     let(:tests) { FactoryBot.build_list(:codeharbor_test, 2) }
+
+    #     it 'imports the zip exactly how the were exported' do
+    #       expect(import_service).to all be_an_equal_exercise_as(exercise).or be_an_equal_exercise_as(exercise2)
+    #     end
+    #   end
+    # end
+
+    context 'when task in zip has a different uuid' do
+      let(:uuid) { SecureRandom.uuid }
+      let(:new_uuid) { SecureRandom.uuid }
+
+      before do
+        exercise.update(uuid: new_uuid)
+      end
+
+      it 'creates a new Exercise' do
+        expect(import_service.id).not_to be exercise.id
+      end
+    end
+
+    context 'when task in zip has the same uuid and nothing has changed' do
+      let(:uuid) { SecureRandom.uuid }
+
+      it 'updates the old Exercise' do
+        expect(import_service.id).to be exercise.id
+      end
+
+      context 'when another user imports the exercise' do
+        let(:import_user) { FactoryBot.create(:teacher) }
+
+        it 'creates a new Exercise' do
+          expect(import_service.id).not_to be exercise.id
+        end
+      end
+    end
+  end
+end
diff --git a/spec/support/expectations/equal_exercise.rb b/spec/support/expectations/equal_exercise.rb
new file mode 100644
index 00000000..df21ec3d
--- /dev/null
+++ b/spec/support/expectations/equal_exercise.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'rspec/expectations'
+
+RSpec::Matchers.define :be_an_equal_exercise_as do |exercise|
+  match do |actual|
+    equal?(actual, exercise)
+  end
+  failure_message do |actual|
+    "#{actual.inspect} is not equal to \n#{exercise.inspect}. \nLast checked attribute: #{@last_checked}"
+  end
+
+  def equal?(object, other)
+    return false unless object.class == other.class
+    return attributes_equal?(object, other) if object.is_a?(ApplicationRecord)
+    return array_equal?(object, other) if object.is_a?(Array) || object.is_a?(ActiveRecord::Associations::CollectionProxy)
+
+    object == other
+  end
+
+  def attributes_equal?(object, other)
+    other_attributes = attributes_and_associations(other)
+    attributes_and_associations(object).each do |k, v|
+      @last_checked = "#{k}: \n\"#{v}\" vs \n\"#{other_attributes[k]}\""
+      return false unless equal?(other_attributes[k], v)
+    end
+    true
+  end
+
+  def array_equal?(object, other)
+    return true if object == other # for []
+    return false if object.length != other.length
+
+    object.to_a.product(other.to_a).map { |k, v| equal?(k, v) }.any?
+  end
+
+  def attributes_and_associations(object)
+    object.attributes.dup.tap do |attributes|
+      attributes[:files] = object.files if defined? object.files
+    end.except('id', 'created_at', 'updated_at', 'exercise_id', 'uuid', 'import_checksum')
+  end
+end