FIX - rec_delta may be nil

[VGasparini]

Even in update operations, the change set can may be null

So, an error is throw when try to iterate over it

[andrepiske]

oh I see. I guess it can never be nil when generated by irontrail itself (at least it shouldn't) but maybe for synthetic records (e.g. imported records).

Can you please add a test case to check this condition?

this method is currently tested in

iron_trail/spec/models/hotel_spec.rb

Lines 31 to 48 in 53fe04b

	describe 'ChangeModelConcern#compute_changeset' do
	before { hotel }
	let(:cest) { Time.find_zone('Europe/Vienna') }
	let(:trail) { ordered_trails[1] }
	subject(:changeset) { trail.compute_changeset }
	it 'has the right time in Japan' do
	expect(changeset['time_in_japan'][0]).to eq(cest.parse('2023-07-23 14:22:55.021'))
	expect(changeset['time_in_japan'][1]).to eq(cest.parse('2023-10-13T17:16:15.021'))
	end
	it 'has the right time at the Hotel' do
	expect(changeset['hotel_time'][0]).to eq(cest.parse('2023-04-25 15:22:54.833'))
	expect(changeset['hotel_time'][1]).to eq(cest.parse('2023-10-12 16:18:29.422'))
	end
	end

The CONTRIBUTING.md file should help you run tests locally :)