webui-ci: save screenshot on test failure

New decorator: ui_driver.screenshot created. It should be applied on test methods.

Screenshot is saved on each exception except SkipTest.

Configuration:
- add: `save_screenshots: True` to ~/.ipa/ui_test.conf to enable saving screenshots
- optionally add `screenshot_dir: /path/to/dir` to specify target directory
  otherwise screenshots are saved to current directory

Reviewed-By: Adam Misnyovszki <amisnyov@redhat.com>

ipatests/test_webui/ui_driver.py

@@ -24,9 +24,12 @@ Contains browser driver and common tasks.
 """
 
 import nose
+from datetime import datetime
 import time
 import re
 import os
+from functools import wraps
+from nose.plugins.skip import SkipTest
 
 try:
     from selenium import webdriver
@@ -77,6 +80,29 @@ DEFAULT_PORT = 4444
 DEFAULT_TYPE = 'local'
 
 
+def screenshot(fn):
+    """
+    Decorator for saving screenshot on exception (test fail)
+    Should be applied on methods of UI_driver subclasses
+    """
+    @wraps(fn)
+    def screenshot_wrapper(*args):
+        try:
+            return fn(*args)
+        except SkipTest:
+            raise
+        except Exception:
+            self = args[0]
+            name = '%s_%s_%s' % (
+                datetime.now().isoformat(),
+                self.__class__.__name__,
+                fn.__name__)
+            self.take_screenshot(name)
+            raise
+
+    return screenshot_wrapper
+
+
 class UI_driver(object):
     """
     Base class for all UI integration tests
@@ -368,6 +394,14 @@ class UI_driver(object):
         screen = self.get_login_screen()
         return screen and screen.is_displayed()
 
+    def take_screenshot(self, name):
+        if self.config.get('save_screenshots'):
+            scr_dir = self.config.get('screenshot_dir')
+            path = name + '.png'
+            if scr_dir:
+                path = os.path.join(scr_dir, path)
+            self.driver.get_screenshot_as_file(path)
+
     def navigate_to_entity(self, entity, facet=None):
         self.driver.get(self.get_url(entity, facet))
         self.wait_for_request(n=3, d=0.4)