Fix Zendesk import failure on lowest subscription tier, aka "Essential" (fixes #2262)

lib/sequencer/unit/import/zendesk/sub_sequence/base.rb

@@ -39,6 +39,10 @@ class Sequencer
 
             def resource_iteration(&block)
               resource_collection.public_send(resource_iteration_method, &block)
+            rescue ZendeskAPI::Error::NetworkError => e
+              return if e.response.status.to_s == '403' && resource_klass.in?(%w[UserField OrganizationField])
+
+              raise
             end
 
             def resource_collection

spec/lib/sequencer/unit/import/zendesk/organization_fields_spec.rb

@@ -0,0 +1,6 @@
+require 'rails_helper'
+require 'lib/sequencer/unit/import/zendesk/sub_sequence/base_examples'
+
+RSpec.describe Sequencer::Unit::Import::Zendesk::OrganizationFields, sequencer: :unit do
+  include_examples 'Sequencer::Unit::Import::Zendesk::SubSequence::Base'
+end

spec/lib/sequencer/unit/import/zendesk/sub_sequence/base_examples.rb

@@ -0,0 +1,61 @@
+RSpec.shared_examples 'Sequencer::Unit::Import::Zendesk::SubSequence::Base' do
+  before do
+    allow(params[:client]).to receive(collection_name).and_return(client_collection)
+    allow(client_collection).to receive(:all!).and_raise(api_error)
+  end
+
+  let(:params) do
+    {
+      dry_run: false,
+      import_job: instance_double(ImportJob),
+      client: double('ZendeskAPI'),
+      group_map: {},         # required by Tickets
+      organization_map: {},  # required by Tickets
+      ticket_field_map: {},  # required by Tickets
+      user_map: {},          # required by Tickets
+    }
+  end
+
+  let(:collection_name) { described_class.name.demodulize.snakecase.to_sym }
+  let(:client_collection) { double('ZendeskAPI::Collection') }
+  let(:api_error) { ZendeskAPI::Error::NetworkError.new('Mock err msg', response_obj) }
+  let(:response_obj) { double('Faraday::Response') }
+
+  # https://github.com/zammad/zammad/issues/2262
+  context 'for lowest-tier Zendesk subscriptions ("Essential")' do
+    shared_examples 'Zendesk import data (only available on Team tier and up)' do
+      context 'when API returns 403 forbidden during sync' do
+        before { allow(response_obj).to receive(:status).and_return(403) }
+
+        it 'rescues the resulting exception' do
+          expect { process(params) }.not_to raise_error
+        end
+      end
+
+      context 'when API returns other errors' do
+        before { allow(response_obj).to receive(:status).and_return(500) }
+
+        # https://github.com/zammad/zammad/issues/2262
+        it 'does not rescue the resulting exception' do
+          expect { process(params) }.to raise_error(api_error)
+        end
+      end
+    end
+
+    shared_examples 'Zendesk import data (available on all tiers)' do
+      context 'if API returns 403 forbidden during sync' do
+        before { allow(response_obj).to receive(:status).and_return(403) }
+
+        it 'does not rescue the resulting exception' do
+          expect { process(params) }.to raise_error(api_error)
+        end
+      end
+    end
+
+    if described_class.name.demodulize.in?(%w[UserFields OrganizationFields])
+      include_examples 'Zendesk import data (only available on Team tier and up)'
+    else
+      include_examples 'Zendesk import data (available on all tiers)'
+    end
+  end
+end

spec/lib/sequencer/unit/import/zendesk/tickets_spec.rb

@@ -0,0 +1,6 @@
+require 'rails_helper'
+require 'lib/sequencer/unit/import/zendesk/sub_sequence/base_examples'
+
+RSpec.describe Sequencer::Unit::Import::Zendesk::Tickets, sequencer: :unit do
+  include_examples 'Sequencer::Unit::Import::Zendesk::SubSequence::Base'
+end

spec/lib/sequencer/unit/import/zendesk/user_fields_spec.rb

@@ -0,0 +1,6 @@
+require 'rails_helper'
+require 'lib/sequencer/unit/import/zendesk/sub_sequence/base_examples'
+
+RSpec.describe Sequencer::Unit::Import::Zendesk::UserFields, sequencer: :unit do
+  include_examples 'Sequencer::Unit::Import::Zendesk::SubSequence::Base'
+end