Add service to import requirements from csv file

- Add tests

ee/app/services/requirements_management/import_csv_service.rb

+# frozen_string_literal: true
+
+module RequirementsManagement
+  class ImportCsvService
+    def initialize(user, project, csv_io)
+      @user = user
+      @project = project
+      @csv_io = csv_io
+      @results = { success: 0, error_lines: [], parse_error: false }
+    end
+
+    def execute
+      process_csv
+      email_results_to_user
+
+      @results
+    end
+
+    private
+
+    def process_csv
+      csv_data = @csv_io.open(&:read).force_encoding(Encoding::UTF_8)
+
+      csv_parsing_params = {
+        col_sep: detect_col_sep(csv_data.lines.first),
+        headers: true,
+        header_converters: :symbol
+      }
+
+      CSV.new(csv_data, csv_parsing_params).each.with_index(2) do |row, line_no|
+        requirement_attributes = {
+          title:       row[:title],
+          description: row[:description]
+        }
+
+        requirement = RequirementsManagement::CreateRequirementService.new(@project, @user, requirement_attributes).execute
+
+        if requirement.persisted?
+          @results[:success] += 1
+        else
+          @results[:error_lines].push(line_no)
+        end
+      end
+    rescue ArgumentError, CSV::MalformedCSVError
+      @results[:parse_error] = true
+    end
+
+    def email_results_to_user
+      Notify.import_requirements_csv_email(@user.id, @project.id, @results).deliver_later
+    end
+
+    def detect_col_sep(header)
+      if header.include?(",")
+        ","
+      elsif header.include?(";")
+        ";"
+      elsif header.include?("\t")
+        "\t"
+      else
+        raise CSV::MalformedCSVError
+      end
+    end
+  end
+end

ee/spec/services/requirements_management/import_csv_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe RequirementsManagement::ImportCsvService do
+  let(:project) { create(:project) }
+  let(:user) { create(:user) }
+
+  subject do
+    uploader = FileUploader.new(project)
+    uploader.store!(file)
+
+    described_class.new(user, project, uploader).execute
+  end
+
+  describe '#execute' do
+    context 'when user can create requirements' do
+      before do
+        project.add_reporter(user)
+        stub_licensed_features(requirements: true)
+      end
+
+      context 'invalid file' do
+        let(:file) { fixture_file_upload('spec/fixtures/banana_sample.gif') }
+
+        it 'returns invalid file error' do
+          expect(Notify).to receive_message_chain(:import_requirements_csv_email, :deliver_later)
+
+          expect(subject[:success]).to eq(0)
+          expect(subject[:parse_error]).to eq(true)
+        end
+      end
+
+      context 'comma delimited file' do
+        let(:file) { fixture_file_upload('spec/fixtures/csv_comma.csv') }
+
+        it 'imports CSV without errors' do
+          expect(Notify).to receive_message_chain(:import_requirements_csv_email, :deliver_later)
+
+          expect(subject[:success]).to eq(3)
+          expect(subject[:error_lines]).to eq([])
+          expect(subject[:parse_error]).to eq(false)
+        end
+
+        it 'correctly sets the requirement attributes' do
+          expect { subject }.to change { project.requirements.count }.by 3
+
+          expect(project.requirements.reload.last).to have_attributes(
+            title: 'Title with quote"',
+            description: 'Description'
+          )
+        end
+      end
+
+      context 'tab delimited file with error row' do
+        let(:file) { fixture_file_upload('spec/fixtures/csv_tab.csv') }
+
+        it 'imports CSV with some error rows' do
+          expect(Notify).to receive_message_chain(:import_requirements_csv_email, :deliver_later)
+
+          expect(subject[:success]).to eq(2)
+          expect(subject[:error_lines]).to eq([3])
+          expect(subject[:parse_error]).to eq(false)
+        end
+
+        it 'correctly sets the requirement attributes' do
+          expect { subject }.to change { project.requirements.count }.by 2
+
+          expect(project.requirements.reload.last).to have_attributes(
+            title: 'Hello',
+            description: 'World'
+          )
+        end
+      end
+
+      context 'semicolon delimited file with CRLF' do
+        let(:file) { fixture_file_upload('spec/fixtures/csv_semicolon.csv') }
+
+        it 'imports CSV with a blank row' do
+          expect(Notify).to receive_message_chain(:import_requirements_csv_email, :deliver_later)
+
+          expect(subject[:success]).to eq(3)
+          expect(subject[:error_lines]).to eq([4])
+          expect(subject[:parse_error]).to eq(false)
+        end
+
+        it 'correctly sets the requirement attributes' do
+          expect { subject }.to change { project.requirements.count }.by 3
+
+          expect(project.requirements.reload.last).to have_attributes(
+            title: 'Hello',
+            description: 'World'
+          )
+        end
+      end
+    end
+
+    context 'when user cannot create requirements' do
+      let(:file) { fixture_file_upload('spec/fixtures/csv_comma.csv') }
+
+      it 'raises an exception' do
+        expect { subject }.to raise_error(Gitlab::Access::AccessDeniedError)
+      end
+    end
+  end
+end