Add more integration tests

Add tests for main, app, accessory, traefik and lock commands.
Other commands are generally covered by the main tests.

Also adds some changes to speed up the integration specs:
- Use a persistent volume for the registry so we can push images to to
reuse between runs (also gets around docker hub rate limits)
- Use persistent volume for mrsk gem install, to avoid re-installing
between tests
- Shorter stop wait time
- Shorter connection timeouts on the load balancer

Takes just over 2 minutes to run all tests locally on an M1 Mac
after docker caches are primed.

test/integration/integration_test.rb

@@ -0,0 +1,111 @@
+require "net/http"
+require "test_helper"
+
+class IntegrationTest < ActiveSupport::TestCase
+  setup do
+    docker_compose "up --build -d"
+    wait_for_healthy
+    setup_deployer
+  end
+
+  teardown do
+    docker_compose "down -t 1"
+  end
+
+  private
+    def docker_compose(*commands, capture: false, raise_on_error: true)
+      command = "docker compose #{commands.join(" ")}"
+      succeeded = false
+      if capture
+        result = stdouted { succeeded = system("cd test/integration && #{command}") }
+      else
+        succeeded = system("cd test/integration && #{command}")
+      end
+
+      raise "Command `#{command}` failed with error code `#{$?}`" if !succeeded && raise_on_error
+      result
+    end
+
+    def deployer_exec(*commands, **options)
+      docker_compose("exec deployer #{commands.join(" ")}", **options)
+    end
+
+    def mrsk(*commands, **options)
+      deployer_exec(:mrsk, *commands, **options)
+    end
+
+    def assert_app_is_down
+      response = app_response
+      debug_response_code(response, "502")
+      assert_equal "502", response.code
+    end
+
+    def assert_app_is_up(version: nil)
+      response = app_response
+      debug_response_code(response, "200")
+      assert_equal "200", response.code
+      assert_app_version(version, response) if version
+    end
+
+    def assert_app_not_found
+      response = app_response
+      debug_response_code(response, "404")
+      assert_equal "404", response.code
+    end
+
+    def wait_for_app_to_be_up(timeout: 10, up_count: 3)
+      timeout_at = Time.now + timeout
+      up_times = 0
+      response = app_response
+      while up_times < up_count && timeout_at > Time.now
+        sleep 0.1
+        up_times += 1 if response.code == "200"
+        response = app_response
+      end
+      assert_equal up_times, up_count
+    end
+
+    def app_response
+      Net::HTTP.get_response(URI.parse("http://localhost:12345/version"))
+    end
+
+    def update_app_rev
+      deployer_exec "./update_app_rev.sh"
+      latest_app_version
+    end
+
+    def latest_app_version
+      deployer_exec("git rev-parse HEAD", capture: true)
+    end
+
+    def assert_app_version(version, response)
+      assert_equal version, response.body.strip
+    end
+
+    def wait_for_healthy(timeout: 20)
+      timeout_at = Time.now + timeout
+      while docker_compose("ps -a | tail -n +2 | grep -v '(healthy)' | wc -l", capture: true) != "0"
+        if timeout_at < Time.now
+          docker_compose("ps -a | tail -n +2 | grep -v '(healthy)'")
+          raise "Container not healthy after #{timeout} seconds" if timeout_at < Time.now
+        end
+        sleep 0.1
+      end
+    end
+
+    def setup_deployer
+      deployer_exec("./setup.sh") unless $DEPLOYER_SETUP
+      $DEPLOYER_SETUP = true
+    end
+
+    def debug_response_code(app_response, expected_code)
+      code = app_response.code
+      if code != expected_code
+        puts "Got response code #{code}, here are the traefik logs:"
+        mrsk :traefik, :logs
+        puts "And here are the load balancer logs"
+        docker_compose :logs, :load_balancer
+        puts "Tried to get the response code again and got #{app_response.code}"
+      end
+    end
+end