Quit on `mod1+q' key binding

* Loop our runner until it is "stopped";
* Use the event dispatcher to stop the runner on `mod1+q' key press;
* Tell the manager to grab the `q' key.

features/actions/quit.feature

@@ -0,0 +1,6 @@
+Feature: quit action
+
+  Scenario: quits on keybing press
+    Given uhwm is running
+    When I press the default quit key binding
+    Then uhwm should terminate successfully

features/steps/run_steps.rb

@@ -4,6 +4,15 @@ def uhwm_run options = nil
   @interactive = @process = run command.join ' '
 end
 
+def uhwm_run_wait_ready
+  uhwm_run
+  uhwm_wait_output 'Connected to'
+end
+
+Given /^uhwm is running$/ do
+  uhwm_run_wait_ready
+end
+
 When /^I start uhwm$/ do
   uhwm_run
 end
@@ -15,3 +24,7 @@ end
 Then /^the exit status must be (\d+)$/ do |exit_status|
   assert_exit_status exit_status.to_i
 end
+
+Then /^uhwm should terminate successfully$/ do
+  assert_exit_status 0
+end

features/steps/x_steps.rb

@@ -1,3 +1,11 @@
+def x_key key
+  fail "cannot simulate X key `#{key}'" unless system "xdotool key #{key}"
+end
+
+When /^I press the default quit key binding$/ do
+  x_key 'alt+q'
+end
+
 Then /^it must connect to X display$/ do
   uhwm_wait_output 'Connected to'
   expect(`sockstat -u`.lines.grep /\s+ruby.+\s+#{@process.pid}/)