Improve UAT on layout

* Move cucumber features regarding the layout protocol in
  layout/protocol;
* Add new cucumber features to test uh-layout integration in uh-wm, at
  least simple mapping and focus behavior;
* Add new acceptance testing helpers

features/layout/manage.feature

@@ -1,16 +1,12 @@
 Feature: layout client management
 
-  Scenario: sends the #<< message when telling the layout to manage a client
-    Given a file named layout.rb with:
-      """
-      class Layout
-        def register *_; end
+  Background:
+    Given uhwm is running
 
-        def << client
-          puts client
-        end
-      end
-      """
-    And uhwm is running with options -v -r./layout -l Layout
+  Scenario: maps new client window
     When a window requests to be mapped
-    Then the output must contain the window name
+    Then the window must be mapped
+
+  Scenario: focuses new client window
+    When a window requests to be mapped
+    Then the window must be focused

features/layout/protocol.feature

@@ -0,0 +1,24 @@
+Feature: layout protocol
+
+  Background:
+    Given a file named layout.rb with:
+      """
+      class Layout
+        def register display
+          puts display
+        end
+
+        def << client
+          puts client
+        end
+      end
+      """
+
+  Scenario: tells the layout to register with #register message
+    When I run uhwm with option -r./layout -l Layout
+    Then the output must contain current display
+
+  Scenario: tells the layout to manage a client with #<< message
+    Given uhwm is running with options -v -r./layout -l Layout
+    When a window requests to be mapped
+    Then the output must contain the window name

features/layout/registration.feature

@@ -1,13 +0,0 @@
-Feature: layout registration
-
-  Scenario: sends the #register message to the layout with the display
-    Given a file named layout.rb with:
-      """
-      class Layout
-        def register display
-          puts display
-        end
-      end
-      """
-    When I run uhwm with option -r./layout -l Layout
-    Then the output must contain current display

features/steps/x_steps.rb

@@ -10,3 +10,11 @@ Then /^it must connect to X display$/ do
   uhwm_wait_output 'Connected to'
   expect(x_socket_check uhwm_pid).to be true
 end
+
+Then /^the window must be mapped$/ do
+  expect(x_window_map_state).to eq 'IsViewable'
+end
+
+Then /^the window must be focused$/ do
+  expect(x_focused_window_id).to eq x_window_id
+end

lib/uh/wm/testing/acceptance_helpers.rb

@@ -60,6 +60,10 @@ module Uh
           @x_client ||= XClient.new
         end
 
+        def x_focused_window_id
+          Integer(`xdpyinfo`[/^focus:\s+window\s+(0x\h+)/, 1])
+        end
+
         def x_key key
           fail "cannot simulate X key `#{key}'" unless system "xdotool key #{key}"
         end
@@ -73,6 +77,10 @@ module Uh
           end.any?
         end
 
+        def x_window_id
+          @x_client.window_id
+        end
+
         def x_window_name
           @x_client.window_name
         end
@@ -81,6 +89,10 @@ module Uh
           x_client.map.sync
         end
 
+        def x_window_map_state
+          `xwininfo -id #{x_window_id}`[/Map State: (\w+)/, 1]
+        end
+
         def x_clients_ensure_stop
           @x_client and @x_client.terminate
         end
@@ -135,6 +147,10 @@ module Uh
             end
           end
 
+          def window_id
+            @window.id
+          end
+
           def window_name
             @name
           end