I have some class-based unit tests running in python\'s unittest2 framework. We\'re using Selenium WebDriver, which has a convenient save_screenshot()
method. I
Override fail()
to generate the screenshot and then call TestCase.fail(self)
?
Here is similar approach to @craigds answer, but with directory support and better compatibility with Python 3:
@property
def failureException(self):
class MyFailureException(AssertionError):
def __init__(self_, *args, **kwargs):
screenshot_dir = 'reports/screenshots'
if not os.path.exists(screenshot_dir):
os.makedirs(screenshot_dir)
self.driver.save_screenshot('{0}/{1}.png'.format(screenshot_dir, self.id()))
return super(MyFailureException, self_).__init__(*args, **kwargs)
MyFailureException.__name__ = AssertionError.__name__
return MyFailureException
This was actually found in this blog.
I've extended it further more with argparse
:
parser.add_argument("-r", "--reports-dir", action="store", dest="dir", help="Directory to save screenshots.", default="reports")
so the dir can be specified dynamically either by system variable or passed argument:
screenshot_dir = os.environ.get('REPORTS_DIR', self.args.dir) + '/screenshots'
This is especially useful, if you've additional wrapper to run all your scripts, like a base class.
Found a solution - I can override failureException
:
@property
def failureException(self):
class MyFailureException(AssertionError):
def __init__(self_, *args, **kwargs):
self.b.save_screenshot('%s.png' % self.id())
return super(MyFailureException, self_).__init__(*args, **kwargs)
MyFailureException.__name__ = AssertionError.__name__
return MyFailureException
This seems incredibly hacky but it seems to work so far.
sys.exc_info()
should give you exit information on whether a test failed or not. So something like this:
def tearDown(self):
if sys.exc_info()[0]:
path = os.path.join(os.path.dirname(os.path.abspath(__file__)), '../failures', self.driver.browser)
if not os.path.exists(path):
try:
os.makedirs(path)
except Exception:
# Since this might not be thread safe
pass
filename = '%s.%s.png' % (self.__class__.__name__, self._testMethodName)
file_path = os.path.join(path, filename)
self.driver.get_screenshot_as_file(file_path)
Use a decorator around each test.
The safest way to remember to decorate new tests, or to avoid going back and decorating a bunch of existing tests, is to use a metaclass to wrap all of the test functions. The How to wrap every method of a class? answer provides the basics of what you need.
You probably should filter the functions that are wrapped down to just the tests, e.g.:
class ScreenshotMetaClass(type):
"""Wraps all tests with screenshot_on_error"""
def __new__(meta, classname, bases, classDict):
newClassDict = {}
for attributeName, attribute in classDict.items():
if type(attribute) == FunctionType and 'test' in attributeName.lower():
# replace the function with a wrapped version
attribute = screenshot_on_error(attribute)
newClassDict[attributeName] = attribute
return type.__new__(meta, classname, bases, newClassDict)