require 'rails_helper' describe AsciicastFramesFileUpdater do let(:updater) { described_class.new(file_writer) } let(:file_writer) { double('file_writer') } describe '#update', needs_terminal_bin: true do let(:asciicast) { create(:asciicast) } let(:film) { double('film', :frames => frames) } let(:frames) { [1, 2] } subject { updater.update(asciicast) } before do allow(Film).to receive(:new).with(asciicast.stdout, kind_of(Terminal)) { film } allow(file_writer).to receive(:write_enumerable) do |file, frames| file << frames.to_json end end it 'updates stdout_frames file on asciicast' do subject expect(asciicast.stdout_frames.read).to eq('[1,2]') end end end