Convert jira issues to gitlab issues attributes

This is the first iteraiton
- take only title and description from jira

lib/gitlab/import_formatter.rb

@@ -14,5 +14,10 @@ module Gitlab
       author ||= "Anonymous"
       "*Created by: #{author}*\n\n"
     end
+
+    def assignee_line(assignee)
+      assignee ||= "Anonymous"
+      "*Assigned to: #{assignee}*\n\n"
+    end
   end
 end

lib/gitlab/jira_import/issue_serializer.rb

@@ -3,12 +3,50 @@
 module Gitlab
   module JiraImport
     class IssueSerializer
+      attr_reader :jira_issue, :project, :params, :formatter
+
       def initialize(project, jira_issue, params = {})
+        @jira_issue = jira_issue
+        @project = project
+        @params = params
+        @formatter = Gitlab::ImportFormatter.new
       end
 
       def execute
-        # this is going to be implemented in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/27201
-        {}
+        {
+          iid: params[:iid],
+          project_id: project.id,
+          description: description,
+          title: title,
+          state_id: map_status(jira_issue.status.statusCategory),
+          updated_at: jira_issue.updated,
+          created_at: jira_issue.created,
+          author_id: project.creator_id # TODO: map actual author: https://gitlab.com/gitlab-org/gitlab/-/issues/210580
+        }
+      end
+
+      private
+
+      def title
+        "[#{jira_issue.key}] #{jira_issue.summary}"
+      end
+
+      def description
+        body = []
+        body << formatter.author_line(jira_issue.reporter.displayName)
+        body << formatter.assignee_line(jira_issue.assignee.displayName) if jira_issue.assignee
+        body << jira_issue.description
+
+        body.join
+      end
+
+      def map_status(jira_status_category)
+        case jira_status_category["key"].downcase
+        when 'done'
+          Issuable::STATE_ID_MAP[:closed]
+        else
+          Issuable::STATE_ID_MAP[:opened]
+        end
       end
     end
   end

spec/lib/gitlab/import_formatter_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::ImportFormatter do
+  let(:formatter) { Gitlab::ImportFormatter.new }
+
+  describe '#comment' do
+    it 'creates the correct string' do
+      expect(formatter.comment('Name', '2020-02-02', 'some text')).to eq(
+        "\n\n*By Name on 2020-02-02*\n\nsome text"
+      )
+    end
+  end
+
+  describe '#author_line' do
+    it 'returns the correct string with provided author name' do
+      expect(formatter.author_line('Name')).to eq("*Created by: Name*\n\n")
+    end
+
+    it 'returns the correct string with Anonymous name if author not provided' do
+      expect(formatter.author_line(nil)).to eq("*Created by: Anonymous*\n\n")
+    end
+  end
+
+  describe '#assignee_line' do
+    it 'returns the correct string with provided author name' do
+      expect(formatter.assignee_line('Name')).to eq("*Assigned to: Name*\n\n")
+    end
+
+    it 'returns the correct string with Anonymous name if author not provided' do
+      expect(formatter.assignee_line(nil)).to eq("*Assigned to: Anonymous*\n\n")
+    end
+  end
+end

spec/lib/gitlab/jira_import/issue_serializer_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::JiraImport::IssueSerializer do
+  describe '#execute' do
+    let_it_be(:project) { create(:project) }
+
+    let(:iid) { 5 }
+    let(:key) { 'PROJECT-5' }
+    let(:summary) { 'some title' }
+    let(:description) { 'basic description' }
+    let(:created_at) { '2020-01-01 20:00:00' }
+    let(:updated_at) { '2020-01-10 20:00:00' }
+    let(:assignee) { double(displayName: 'Solver') }
+    let(:jira_status) { 'new' }
+    let(:jira_issue) do
+      double(
+        id: '1234',
+        key: key,
+        summary: summary,
+        description: description,
+        created: created_at,
+        updated: updated_at,
+        assignee: assignee,
+        reporter: double(displayName: 'Reporter'),
+        status: double(statusCategory: { 'key' => jira_status })
+      )
+    end
+    let(:params) { { iid: iid } }
+
+    let(:expected_description) do
+      <<~MD
+        *Created by: Reporter*
+
+        *Assigned to: Solver*
+
+        basic description
+      MD
+    end
+
+    subject { described_class.new(project, jira_issue, params).execute }
+
+    context 'attributes setting' do
+      it 'sets the basic attributes' do
+        expect(subject).to eq(
+          iid: iid,
+          project_id: project.id,
+          description: expected_description.strip,
+          title: "[#{key}] #{summary}",
+          state_id: 1,
+          updated_at: updated_at,
+          created_at: created_at,
+          author_id: project.creator_id
+        )
+      end
+    end
+
+    context 'with done status' do
+      let(:jira_status) { 'done' }
+
+      it 'maps the status to closed' do
+        expect(subject[:state_id]).to eq(2)
+      end
+    end
+
+    context 'without the assignee' do
+      let(:assignee) { nil }
+
+      it 'does not include assignee in the description' do
+        expected_description = <<~MD
+          *Created by: Reporter*
+
+          basic description
+        MD
+
+        expect(subject[:description]).to eq(expected_description.strip)
+      end
+    end
+
+    context 'without the iid' do
+      let(:params) { {} }
+
+      it 'does not set the iid' do
+        expect(subject[:iid]).to be_nil
+      end
+    end
+  end
+end