Fix specs for streamin serializer

- remove uneccesery allow
- reodred lets
- fix " and ' to be

spec/lib/gitlab/import_export/json/streaming_serializer_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::ImportExport::JSON::StreamingSerializer do
+  let_it_be(:user) { create(:user) }
+  let_it_be(:release) { create(:release) }
+  let_it_be(:group) { create(:group) }
+
+  let_it_be(:exportable) do
+    create(:project,
+      :public,
+      :repository,
+      :issues_disabled,
+      :wiki_enabled,
+      :builds_private,
+      description: 'description',
+      releases: [release],
+      group: group,
+      approvals_before_merge: 1)
+  end
+  let_it_be(:issue) do
+    create(:issue,
+      assignees: [user],
+      project: exportable)
+  end
+
+  let(:exportable_path) { 'project' }
+  let(:json_writer) { instance_double('Gitlab::ImportExport::JSON::LegacyWriter') }
+  let(:hash) { { name: exportable.name, description: exportable.description }.stringify_keys }
+  let(:include) { [] }
+
+  let(:relations_schema) do
+    {
+      only: [:name, :description],
+      include: include,
+      preload: { issues: nil }
+    }
+  end
+
+  subject do
+    described_class.new(exportable, relations_schema, json_writer, exportable_path: exportable_path)
+  end
+
+  describe '#execute' do
+    before do
+      allow(json_writer).to receive(:write_attributes).with(exportable_path, hash)
+    end
+
+    it 'calls json_writer.write_attributes with proper params' do
+      subject.execute
+    end
+
+    context 'with many relations' do
+      let(:include) do
+        [{ issues: { include: [] } }]
+      end
+
+      it 'calls json_writer.write_relation_array with proper params' do
+        expect(json_writer).to receive(:write_relation_array).with(exportable_path, :issues, array_including(issue.to_json))
+
+        subject.execute
+      end
+    end
+
+    context 'with single relation' do
+      let(:group_options) do
+        { include: [], only: [:name, :path, :description] }
+      end
+      let(:include) do
+        [{ group: group_options }]
+      end
+
+      it 'calls json_writer.write_relation with proper params' do
+        expect(json_writer).to receive(:write_relation).with(exportable_path, :group, group.to_json(group_options))
+
+        subject.execute
+      end
+    end
+
+    context 'with array relation' do
+      let(:project_member) { create(:project_member, user: user) }
+      let(:include) do
+        [{ project_members: { include: [] } }]
+      end
+
+      before do
+        allow(exportable).to receive(:project_members).and_return([project_member])
+      end
+
+      it 'calls json_writer.write_relation_array with proper params' do
+        expect(json_writer).to receive(:write_relation_array).with(exportable_path, :project_members, array_including(project_member.to_json))
+
+        subject.execute
+      end
+    end
+  end
+end