Add add_and_match_order method to orderbook

lib/rex/order_book.rb

@@ -2,7 +2,10 @@ require "rbtree"
 
 module Rex
   class OrderBook
-    def initialize
+    class NoMatcherProvidedError < StandardError; end
+
+    def initialize(matcher: Matcher.new)
+      @matcher = matcher
       @sell_side = RBTree.new
       @buy_side = RBTree.new
       @order_ids = {} # order_id => order
@@ -17,6 +20,11 @@ module Rex
       order_ids[order.id] = order
     end
 
+    def add_and_match_order(order)
+      add_order(order)
+      @matcher.match(self)
+    end
+
     def remove_order(order_id)
       order = order_ids[order_id]
       return nil if order.nil?

spec/matcher_spec.rb

@@ -9,7 +9,6 @@ RSpec.describe Rex::Matcher do
     let(:cheaper_sell_order) { build(:order, price: 99, is_buy: false, amount: 50, remaining_amount: 50) }
     let(:pricier_sell_order) { build(:order, price: 100, is_buy: false, amount: 70, remaining_amount: 70) }
 
-
     context "when order book has unmatched orders" do
       before do
         order_book.add_order(buy_order)

spec/order_book_spec.rb

@@ -49,6 +49,28 @@ RSpec.describe Rex::OrderBook do
     end
   end
 
+  describe "add_and_match_order" do
+    context "when matcher is given" do
+      let(:matcher) { instance_double(Rex::Matcher) }
+      let(:instance) { described_class.new(matcher: matcher) }
+      let(:order) { build(:order, is_buy: true, price: 100) }
+
+      before do
+        allow(matcher).to receive(:match).with(instance)
+      end
+
+      it "adds the order" do
+        expect(instance).to receive(:add_order).with(order)
+        instance.add_and_match_order(order)
+      end
+
+      it "calls the matcher" do
+        expect(matcher).to receive(:match).with(instance)
+        instance.add_and_match_order(order)
+      end
+    end
+  end
+
   describe "#highest_buy_order" do
     context "when there is nothing in the book" do
       it "returns nil " do
@@ -96,7 +118,7 @@ RSpec.describe Rex::OrderBook do
   end
 
   describe "#next_trade_id" do
-    it 'returns an increasing trade id' do
+    it "returns an increasing trade id" do
       expect(instance.next_trade_id).to eq(1)
       expect(instance.next_trade_id).to eq(2)
       expect(instance.next_trade_id).to eq(3)