Recreate EventClassRemapper in contrib/transformations

Author: lukaszreszke

Diff for: contrib/ruby_event_store-transformations/lib/ruby_event_store/transformations/event_class_remapper.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module RubyEventStore
+  module Transformations
+    class EventClassRemapper
+      def initialize(class_map)
+        @class_map = class_map
+      end
+
+      def dump(record)
+        record
+      end
+
+      def load(record)
+        Record.new(
+          event_id: record.event_id,
+          event_type: class_map[record.event_type] || record.event_type,
+          data: record.data,
+          metadata: record.metadata,
+          timestamp: record.timestamp,
+          valid_at: record.valid_at
+        )
+      end
+
+      private
+
+      attr_reader :class_map
+    end
+  end
+end

Diff for: contrib/ruby_event_store-transformations/spec/event_class_remapper_spec.rb

@@ -0,0 +1,39 @@
+require "spec_helper"
+
+module RubyEventStore
+  module Transformations
+    ::RSpec.describe EventClassRemapper do
+      let(:time) { Time.now.utc }
+      let(:uuid) { SecureRandom.uuid }
+
+      def record(event_type: "TestEvent")
+        Record.new(
+          event_id: uuid,
+          metadata: {
+            some: "meta"
+          },
+          data: {
+            some: "value"
+          },
+          event_type: event_type,
+          timestamp: time,
+          valid_at: time
+        )
+      end
+
+      let(:changeable_record) { record(event_type: "EventNameBeforeRefactor") }
+      let(:changed_record) { record(event_type: "SomethingHappened") }
+      let(:class_map) { { "EventNameBeforeRefactor" => "SomethingHappened" } }
+
+      specify "#dump" do
+        expect(EventClassRemapper.new(class_map).dump(record)).to eq(record)
+        expect(EventClassRemapper.new(class_map).dump(record)).to eq(record)
+      end
+
+      specify "#load" do
+        expect(EventClassRemapper.new(class_map).load(record)).to eq(record)
+        expect(EventClassRemapper.new(class_map).load(changeable_record)).to eq(changed_record)
+      end
+    end
+  end
+end