add tests for controllers and ActionCable channels; improve main backend docs

main-server/spec/channels/matchmaking_channel_spec.rb

@@ -0,0 +1,68 @@
+require "rails_helper"
+
+RSpec.describe MatchmakingChannel, type: :channel do
+  let(:user) { User.create!(nickname: "Blackbeard", password: "password123", rating: 1250) }
+
+  before do
+    stub_connection current_user: user
+  end
+
+  describe "#subscribed" do
+    it "subscribes successfully and streams from the user's private channel" do
+      subscribe
+      expect(subscription).to be_confirmed
+      expect(subscription).to have_stream_from("matchmaking:#{user.id}")
+      expect(transmissions).to be_empty
+    end
+
+    it "transmits a claimed match if one was ready before or during connection" do
+      match_payload = {
+        type: "matched",
+        match_id: "test-match-uuid",
+        game_token: "jwt-game-token",
+        game_server: "ws://localhost:8080",
+        players: [ user.id, 999 ]
+      }
+      allow(MatchmakingService).to receive(:claim).with(user.id).and_return(match_payload)
+
+      subscribe
+
+      expect(subscription).to be_confirmed
+      expect(transmissions.last).to eq(match_payload.as_json)
+    end
+  end
+
+  describe "#start" do
+    it "calls MatchmakingService.enqueue with the user's id and current rating" do
+      subscribe
+
+      expect(MatchmakingService).to receive(:enqueue).with(user.id, rating: 1250)
+      perform :start
+    end
+
+    it "accepts extra parameters in data hash without error" do
+      subscribe
+
+      expect(MatchmakingService).to receive(:enqueue).with(user.id, rating: 1250)
+      perform :start, { "custom" => "data" }
+    end
+  end
+
+  describe "#stop" do
+    it "calls MatchmakingService.cancel for the current user" do
+      subscribe
+
+      expect(MatchmakingService).to receive(:cancel).with(user.id)
+      perform :stop
+    end
+  end
+
+  describe "#unsubscribed" do
+    it "cancels matchmaking search when unsubscribing" do
+      subscribe
+
+      expect(MatchmakingService).to receive(:cancel).with(user.id)
+      unsubscribe
+    end
+  end
+end