Fixed issue #2040: Zendesk import: To/From extraction for system comments fails.

lib/sequencer/unit/import/zendesk/ticket/comment/source_based.rb

@@ -9,9 +9,12 @@ class Sequencer
               uses :resource
 
               def value
-                method_name = resource.via.channel.to_sym
-                return if !respond_to?(method_name, true)
-                send(method_name)
+                return if private_methods(false).exclude?(value_method_name)
+                send(value_method_name)
+              end
+
+              def value_method_name
+                @value_method_name ||= resource.via.channel.to_sym
               end
             end
           end

spec/lib/sequencer/unit/import/zendesk/ticket/comment/source_based_spec.rb

@@ -0,0 +1,39 @@
+require 'rails_helper'
+
+RSpec.describe Sequencer::Unit::Import::Zendesk::Ticket::Comment::SourceBased, sequencer: :unit do
+
+  before(:all) do
+
+    described_class.class_eval do
+
+      private
+
+      def email
+        'test@example.com'
+      end
+    end
+  end
+
+  def parameters_for_channel(channel)
+    {
+      resource: double(
+        via: double(
+          channel: channel
+        )
+      )
+    }
+  end
+
+  context 'for resource.via.channel attribute' do
+
+    it 'provides from existing method' do
+      provided = process(parameters_for_channel('email'))
+      expect(provided[:source_based]).to eq('test@example.com')
+    end
+
+    it 'provides nil for non existing method' do
+      provided = process(parameters_for_channel('system'))
+      expect(provided[:source_based]).to be_nil
+    end
+  end
+end