Fix aggressive prune breaking rollback

In the image prune command --all overrides --dangling=true. This removes
the image git sha image tag for the latest image which prevented
us from rolling back to it.

I've updated the integration test to now test deploy, redeploy and
rollback.

test/integration/deploy_test.rb

@@ -13,11 +13,36 @@ class DeployTest < ActiveSupport::TestCase
   end
 
   test "deploy" do
+    first_version = latest_app_version
+
     assert_app_is_down
 
     mrsk :deploy
 
-    assert_app_is_up
+    assert_app_is_up version: first_version
+
+    second_version = update_app_rev
+
+    mrsk :redeploy
+
+    assert_app_is_up version: second_version
+
+    mrsk :rollback, first_version
+
+    assert_app_is_up version: first_version
+
+    details = mrsk :details, capture: true
+
+    assert_match /Traefik Host: vm1/, details
+    assert_match /Traefik Host: vm2/, details
+    assert_match /App Host: vm1/, details
+    assert_match /App Host: vm2/, details
+    assert_match /traefik:v2.9/, details
+    assert_match /registry:4443\/app:#{first_version}/, details
+
+    audit = mrsk :audit, capture: true
+
+    assert_match /Booted app version #{first_version}.*Booted app version #{second_version}.*Booted app version #{first_version}.*/m, audit
   end
 
   private
@@ -34,23 +59,19 @@ class DeployTest < ActiveSupport::TestCase
       result
     end
 
-    def deployer_exec(*commands, capture: false)
-      if capture
-        stdouted { docker_compose("exec deployer #{commands.join(" ")}") }
-      else
-        docker_compose("exec deployer #{commands.join(" ")}", capture: capture)
-      end
+    def deployer_exec(*commands, **options)
+      docker_compose("exec deployer #{commands.join(" ")}", **options)
     end
 
-    def mrsk(*commands, capture: false)
-      deployer_exec(:mrsk, *commands, capture: capture)
+    def mrsk(*commands, **options)
+      deployer_exec(:mrsk, *commands, **options)
     end
 
     def assert_app_is_down
       assert_equal "502", app_response.code
     end
 
-    def assert_app_is_up
+    def assert_app_is_up(version: nil)
       code = app_response.code
       if code != "200"
         puts "Got response code #{code}, here are the traefik logs:"
@@ -60,12 +81,44 @@ class DeployTest < ActiveSupport::TestCase
         puts "Tried to get the response code again and got #{app_response.code}"
       end
       assert_equal "200", code
+      assert_app_version(version) if version
+    end
+
+    def assert_app_not_found
+      assert_equal "404", app_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"))
     end
 
+    def update_app_rev
+      deployer_exec "./update_app_rev.sh"
+      latest_app_version
+    end
+
+    def latest_app_version
+      deployer_exec("cat version", capture: true)
+    end
+
+    def assert_app_version(version)
+      actual_version = Net::HTTP.get_response(URI.parse("http://localhost:12345/version")).body.strip
+
+      assert_equal version, actual_version
+    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"