Add support for event pattern matching

ruby_event_store/lib/ruby_event_store/event.rb

@@ -123,6 +123,21 @@ def correlate_with(other_message)
       self
     end
 
+    # Returns a hash of the name/value pairs for the given event attributes.
+    #
+    # @param attributes [Array] attributes to deconstruct
+    # @return [Hash] deconstructed event
+    def deconstruct_keys(attributes)
+      {
+        causation_id: causation_id,
+        correlation_id: correlation_id,
+        data: data,
+        event_id: event_id,
+        event_type: event_type,
+        metadata: metadata.to_h
+      }.slice(*attributes)
+    end
+
     alias_method :eql?, :==
   end
 end

ruby_event_store/spec/get_event_spec.rb

@@ -187,6 +187,49 @@ module RubyEventStore
       expect(event.event_type).to eq("Doh")
     end
 
+    specify "pattern matching" do
+      test_created = Test::TestCreated.new(
+        event_id: "foo",
+        data: { foo: "foo", bar: "bar" },
+        metadata: { user_id: 42, correlation_id: "coid", causation_id: "caid" }
+      )
+
+      # match by class
+      expect(test_created).to satisfy { |event| event in Test::TestCreated }
+      expect(test_created).to satisfy { |event| event in {} }
+      expect(test_created).to_not satisfy { |event| event in Test::TestDeleted }
+
+      # match by event id
+      expect(test_created).to satisfy { |event| event in Test::TestCreated(event_id: "foo") }
+      expect(test_created).to satisfy { |event| event in { event_id: "foo" } }
+      expect(test_created).to_not satisfy { |event| event in Test::TestCreated(event_id: "bar") }
+
+      # match by event type
+      expect(test_created).to satisfy { |event| event in Test::TestCreated(event_type: "Test::TestCreated") }
+      expect(test_created).to satisfy { |event| event in { event_type: "Test::TestCreated" } }
+      expect(test_created).to_not satisfy { |event| event in { event_type: "Test::TestDeleted" } }
+
+      # match by causation id
+      expect(test_created).to satisfy { |event| event in Test::TestCreated(causation_id: "caid") }
+      expect(test_created).to satisfy { |event| event in { causation_id: "caid"} }
+      expect(test_created).to_not satisfy { |event| event in { causation_id: "foo"} }
+
+      # match by correlation id
+      expect(test_created).to satisfy { |event| event in Test::TestCreated(correlation_id: "coid") }
+      expect(test_created).to satisfy { |event| event in { correlation_id: "coid"} }
+      expect(test_created).to_not satisfy { |event| event in { correlation_id: "foo"} }
+
+      # match by data
+      expect(test_created).to satisfy { |event| event in Test::TestCreated(data: { foo: "foo" }) }
+      expect(test_created).to satisfy { |event| event in { data: { foo: "foo" } } }
+      expect(test_created).to_not satisfy { |event| event in Test::TestCreated(data: { foo: "bar" }) }
+
+      # match by metadata
+      expect(test_created).to satisfy { |event| event in Test::TestCreated(metadata: { user_id: 42 }) }
+      expect(test_created).to satisfy { |event| event in { metadata: { user_id: 42 } } }
+      expect(test_created).to_not satisfy { |event| event in Test::TestCreated(metedata: { user_id: 41 }) }
+    end
+
     specify do
       event_id = SecureRandom.uuid
       one = Event.new(event_id: event_id, data: { yes: :no }, metadata: { event_type: "one" })