add repository spec

spec/lib/gitlab/backup/repository_spec.rb

+require 'spec_helper'
+
+describe Backup::Repository, lib: true do
+  include StubENV
+
+  let(:progress) { StringIO.new }
+  let!(:project) { create(:empty_project) }
+
+  before do
+    allow(progress).to receive(:puts)
+    allow(progress).to receive(:print)
+
+    allow_any_instance_of(String).to receive(:color) do |string, _color|
+      string
+    end
+
+    @old_progress = $progress # rubocop:disable Style/GlobalVars
+    $progress = progress # rubocop:disable Style/GlobalVars
+  end
+
+  after do
+    $progress = @old_progress # rubocop:disable Style/GlobalVars
+  end
+
+  describe 'repo failure' do
+    before do
+      allow_any_instance_of(Project).to receive(:empty_repo?).and_raise(Rugged::OdbError)
+      allow(Gitlab::Popen).to receive(:popen).and_return(['normal output', 0])
+    end
+
+    it 'does not raise error' do
+      expect { described_class.new.dump }.not_to raise_error
+    end
+  end
+end