review: update value with async fetch

1 - spec cover the job which fetches external data

2 - refactor the job with guard clauses

3 - delegate update operation to the champ itself

4 - annuaire education: override the update operation
to let the value be populated by the fetched data

5 - prefilling: don't fetch data synchronously

spec/models/champs/annuaire_education_champ_spec.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Champs::AnnuaireEducationChamp do
+  describe '#update_with_external_data!' do
+    let(:champ) { create(:champ_annuaire_education, data: "any data") }
+    subject { champ.update_with_external_data!(data: data) }
+
+    shared_examples "a data updater (without updating the value)" do |data|
+      it { expect { subject }.to change { champ.reload.data }.to(data) }
+      it { expect { subject }.not_to change { champ.reload.value } }
+    end
+
+    context 'when data is nil' do
+      let(:data) { nil }
+      it_behaves_like "a data updater (without updating the value)", nil
+    end
+
+    context 'when data is empty' do
+      let(:data) { '' }
+      it_behaves_like "a data updater (without updating the value)", ''
+    end
+
+    context 'when data is inconsistent' do
+      let(:data) { { 'yo' => 'lo' } }
+      it_behaves_like "a data updater (without updating the value)", { 'yo' => 'lo' }
+    end
+
+    context 'when data is consistent' do
+      let(:data) {
+        {
+          'nom_etablissement': "karrigel an ankou",
+          'nom_commune' => 'kumun',
+          'identifiant_de_l_etablissement' => '666667'
+        }.with_indifferent_access
+      }
+      it { expect { subject }.to change { champ.reload.data }.to(data) }
+      it { expect { subject }.to change { champ.reload.value }.to('karrigel an ankou, kumun (666667)') }
+    end
+  end
+end