def assertScreenshot(self, selector, path):
"""
Assert that the element as defined by the passed CSS `selector` is
the same as the one saved in the baseline screenshot.
Note that this method will generate a baseline screenshot if the
make_baseline_screenshots config option is set to true. No assertions
will occur.
:param unicode selector: CSS selector of element to screenshot.
:param path: URL path to page where element is found.
"""
for display_name, browser_name, driver in self._yield_drivers():
url = self._make_url(path)
driver.get(url)
# selenium checks for a str instance. Unicode would fail here.
element = driver.find_element_by_css_selector(str(selector))
sleep(1)
screenshot = element.get_screenshot()
baseline_path = self._make_screenshot_path(
self._BASELINE_FOLDER_NAME, browser_name, display_name)
baseline_file = '{}/{}--{}.png'.format(baseline_path, path,
selector)
# Create the directory if it does not exist.
if not os.path.exists(baseline_path):
os.makedirs(baseline_path)
if self._make_baseline_screenshots:
screenshot.save(baseline_file)
log.warning(
'Creating baseline screenshot: {}'.format(baseline_file))
else:
try:
baseline_screenshot = Image.open(baseline_file).convert(
'RGB')
except IOError:
raise MissingBaselineScreenshotException
error_path = self._make_screenshot_path(
self._ERROR_FOLDER_NAME, browser_name, display_name)
if not os.path.exists(error_path):
os.makedirs(error_path)
error_file = '{}/{}--{}.png'.format(error_path, path, selector)
try:
diff = ImageDiff(screenshot, baseline_screenshot)
except AssertionError:
screenshot.save(error_file)
raise AssertScreenshotException(error_file)
distance = abs(diff.get_distance())
if distance > self._THRESHOLD:
screenshot.save(error_file)
raise AssertScreenshotException(distance)
driver.close()
def assertSameFiles(self, output_file, baseline_file, threshold):
output_image = Image.open(output_file).convert('RGB')
baseline_image = Image.open(baseline_file).convert('RGB')
diff = ImageDiff(output_image, baseline_image)
distance = abs(diff.get_distance())
if distance > threshold:
raise AssertionError("The new screenshot '%s' did not match "
"the baseline '%s' (by a distance of %.2f)" %
(output_file, baseline_file, distance))
def assertSameFiles(self, output_file, baseline_file, threshold):
output_image = Image.open(output_file).convert('RGB')
baseline_image = Image.open(baseline_file).convert('RGB')
diff = ImageDiff(output_image, baseline_image)
distance = abs(diff.get_distance())
if distance > threshold:
raise AssertionError("The new screenshot '%s' did not match "
"the baseline '%s' (by a distance of %.2f)"
% (output_file, baseline_file, distance))
def test_distance_all_channels(self):
diff = ImageDiff(self.get_white_image(), self.get_black_image())
self.assertAlmostEqual(diff.get_distance(), 100 * 100, delta=0.001)
def test_nrmsd_half_filled(self):
diff = ImageDiff(self.get_black_image(), self.get_half_filled_image())
self.assertEqual(diff.get_nrmsd(), math.sqrt(0.5))
def test_nrmsd_one_channel(self):
diff = ImageDiff(self.get_image((255, 0, 0)), self.get_black_image())
self.assertEqual(diff.get_nrmsd(), math.sqrt(1.0 / 3))
def test_nrmsd_all_channels(self):
diff = ImageDiff(self.get_white_image(), self.get_black_image())
self.assertEqual(diff.get_nrmsd(), 1)
def test_distance_half_filled(self):
diff = ImageDiff(self.get_black_image(), self.get_half_filled_image())
self.assertAlmostEqual(diff.get_distance(), 10000.0 / 2, delta=0.001)
def assertScreenshot(self, selector, path):
"""
Assert that the element as defined by the passed CSS `selector` is
the same as the one saved in the baseline screenshot.
Note that this method will generate a baseline screenshot if the
make_baseline_screenshots config option is set to true. No assertions
will occur.
:param unicode selector: CSS selector of element to screenshot.
:param path: URL path to page where element is found.
"""
for display_name, browser_name, driver in self._yield_drivers():
url = self._make_url(path)
driver.get(url)
# selenium checks for a str instance. Unicode would fail here.
element = driver.find_element_by_css_selector(str(selector))
sleep(1)
screenshot = element.get_screenshot()
baseline_path = self._make_screenshot_path(
self._BASELINE_FOLDER_NAME,
browser_name,
display_name)
baseline_file = '{}/{}--{}.png'.format(
baseline_path,
path,
selector)
# Create the directory if it does not exist.
if not os.path.exists(baseline_path):
os.makedirs(baseline_path)
if self._make_baseline_screenshots:
screenshot.save(baseline_file)
log.warning('Creating baseline screenshot: {}'.format(
baseline_file))
else:
try:
baseline_screenshot = Image.open(baseline_file).convert('RGB')
except IOError:
raise MissingBaselineScreenshotException
error_path = self._make_screenshot_path(
self._ERROR_FOLDER_NAME,
browser_name,
display_name)
if not os.path.exists(error_path):
os.makedirs(error_path)
error_file = '{}/{}--{}.png'.format(
error_path,
path,
selector)
try:
diff = ImageDiff(screenshot, baseline_screenshot)
except AssertionError:
screenshot.save(error_file)
raise AssertScreenshotException(error_file)
distance = abs(diff.get_distance())
if distance > self._THRESHOLD:
screenshot.save(error_file)
raise AssertScreenshotException(distance)
driver.close()
def compareScreenshot(self, element_or_selector, file, threshold=0):
"""
Assert that a screenshot of an element is the same as a screenshot on disk,
within a given threshold.
:param element_or_selector:
Either a CSS selector as a string or a
:py:class:`~needle.driver.NeedleWebElementMixin` object that represents
the element to capture.
:param file:
If a string, then assumed to be the filename for the screenshot,
which will be appended with ``.png``. Otherwise assumed to be
a file object for the baseline image.
:param threshold:
The threshold for triggering a test failure.
"""
yield # To allow using this method as a context manager
if not isinstance(element_or_selector, NeedleWebElementMixin):
element = self.driver.find_element_by_css_selector(
element_or_selector)
else:
element = element_or_selector
if not isinstance(file, basestring):
# Comparing in-memory files instead of on-disk files
baseline_image = Image.open(file).convert('RGB')
fresh_screenshot = element.get_screenshot()
diff = ImageDiff(fresh_screenshot, baseline_image)
distance = abs(diff.get_distance())
if distance > threshold:
raise AssertionError("The new screenshot did not match "
"the baseline (by a distance of %.2f)" %
distance)
else:
baseline_file = os.path.join(self.baseline_directory,
'%s.png' % file)
output_file = os.path.join(self.output_directory, '%s.png' % file)
# Determine whether we should save the baseline image
save_baseline = False
if self.save_baseline:
save_baseline = True
elif self.capture:
warn(
"The 'NeedleTestCase.capture' attribute and '--with-save-baseline' nose option "
"are deprecated since version 0.2.0. Use 'save_baseline' and '--with-save-baseline' "
"instead. See the changelog for more information.",
PendingDeprecationWarning)
if os.path.exists(baseline_file):
self.skipTest(
'Not capturing %s, its baseline image already exists. If you '
'want to capture this element again, delete %s' %
(file, baseline_file))
else:
save_baseline = True
if save_baseline:
# Save the baseline screenshot and bail out
element.get_screenshot().save(baseline_file)
return
else:
if not os.path.exists(baseline_file):
raise IOError(
'The baseline screenshot %s does not exist. '
'You might want to re-run this test in baseline-saving mode.'
% baseline_file)
# Save the new screenshot
element.get_screenshot().save(output_file)
try:
self.engine.assertSameFiles(output_file, baseline_file,
threshold)
except:
raise
else:
if self.cleanup_on_success:
os.remove(output_file)
def test_nrmsd_half_filled(self):
diff = ImageDiff(self.get_black_image(), self.get_half_filled_image())
self.assertEqual(diff.get_nrmsd(), math.sqrt(0.5))
def test_nrmsd_one_channel(self):
diff = ImageDiff(self.get_image((255, 0, 0)), self.get_black_image())
self.assertEqual(diff.get_nrmsd(), math.sqrt(1.0 / 3))
def test_nrmsd_all_channels(self):
diff = ImageDiff(self.get_white_image(), self.get_black_image())
self.assertEqual(diff.get_nrmsd(), 1)
def assert_screenshot(self,
file_path,
element_or_selector=None,
threshold=0,
exclude=None):
"""Fail if new fresh image is too dissimilar from the baseline image
.. note:: From needle
https://github.com/python-needle/needle/blob/master/needle/cases.py#L161
:param str file_path: File name for baseline image
:param element_or_selector: WebElement or tuple containing selector ex. ('id', 'mainPage')
:param threshold: Distance threshold
:param list exclude: Elements or element selectors for areas to exclude
:return:
"""
element = self._find_element(
element_or_selector) if element_or_selector else None
# Get baseline screenshot
self._create_dir(self.baseline_dir)
baseline_image = os.path.join(self.baseline_dir, '%s.png' % file_path) \
if isinstance(file_path, basestring) else Image.open(file_path).convert('RGB')
# Take screenshot and exit if in baseline saving mode
if self.save_baseline:
self.get_screenshot_as_image(element,
exclude=exclude).save(baseline_image)
return
# Get fresh screenshot
self._create_dir(self.output_dir)
fresh_image = self.get_screenshot_as_image(element, exclude=exclude)
fresh_image_file = os.path.join(self.output_dir, '%s.png' % file_path)
fresh_image.save(fresh_image_file)
# Error if there is not a baseline image to compare
if not self.save_baseline and not isinstance(
file_path, basestring) and not os.path.exists(baseline_image):
raise IOError(
'The baseline screenshot %s does not exist. You might want to '
're-run this test in baseline-saving mode.' % baseline_image)
# Compare images
if isinstance(baseline_image, basestring):
try:
self.engine.assertSameFiles(fresh_image_file, baseline_image,
threshold)
except AssertionError as err:
msg = getattr(err, 'message', err.args[0] if err.args else "")
args = err.args[1:] if len(err.args) > 1 else []
raise ImageMismatchException(msg, baseline_image,
fresh_image_file, args)
except EnvironmentError:
msg = "Missing baseline '{}'. Please run again with --needle-save-baseline".format(
baseline_image)
raise MissingBaselineException(msg)
except ValueError as err:
if self.options['needle_engine'] == 'imagemagick':
msg = "It appears {0} is not installed. Please verify {0} is installed or choose a different engine"
raise MissingEngineException(
msg.format(self.options['needle_engine']))
raise err
finally:
if self.cleanup_on_success:
os.remove(fresh_image_file)
else:
diff = ImageDiff(fresh_image, baseline_image)
distance = abs(diff.get_distance())
if distance > threshold:
pytest.fail(
'Fail: New screenshot did not match the baseline (by a distance of %.2f)'
% distance)
def test_distance_one_channel(self):
diff = ImageDiff(self.get_image((255, 0, 0)), self.get_black_image())
self.assertAlmostEqual(diff.get_distance(), 10000.0 / 3, delta=0.001)
def test_distance_all_channels(self):
diff = ImageDiff(self.get_white_image(), self.get_black_image())
self.assertAlmostEqual(diff.get_distance(), 100 * 100, delta=0.001)
def test_distance_half_filled(self):
diff = ImageDiff(self.get_black_image(), self.get_half_filled_image())
self.assertAlmostEqual(diff.get_distance(), 10000.0 / 2, delta=0.001)
def test_distance_one_channel(self):
diff = ImageDiff(self.get_image((255, 0, 0)), self.get_black_image())
self.assertAlmostEqual(diff.get_distance(), 10000.0 / 3, delta=0.001)
def compareScreenshot(self, element_or_selector, file, threshold=0):
"""
Assert that a screenshot of an element is the same as a screenshot on disk,
within a given threshold.
:param element_or_selector:
Either a CSS selector as a string or a
:py:class:`~needle.driver.NeedleWebElementMixin` object that represents
the element to capture.
:param file:
If a string, then assumed to be the filename for the screenshot,
which will be appended with ``.png``. Otherwise assumed to be
a file object for the baseline image.
:param threshold:
The threshold for triggering a test failure.
"""
yield # To allow using this method as a context manager
if not isinstance(element_or_selector, NeedleWebElementMixin):
element = self.driver.find_element_by_css_selector(element_or_selector)
else:
element = element_or_selector
if not isinstance(file, basestring):
# Comparing in-memory files instead of on-disk files
baseline_image = Image.open(file).convert('RGB')
fresh_screenshot = element.get_screenshot()
diff = ImageDiff(fresh_screenshot, baseline_image)
distance = abs(diff.get_distance())
if distance > threshold:
raise AssertionError("The new screenshot did not match "
"the baseline (by a distance of %.2f)"
% distance)
else:
baseline_file = os.path.join(self.baseline_directory, '%s.png' % file)
output_file = os.path.join(self.output_directory, '%s.png' % file)
# Determine whether we should save the baseline image
save_baseline = False
if self.save_baseline:
save_baseline = True
elif self.capture:
warn("The 'NeedleTestCase.capture' attribute and '--with-save-baseline' nose option "
"are deprecated since version 0.2.0. Use 'save_baseline' and '--with-save-baseline' "
"instead. See the changelog for more information.",
PendingDeprecationWarning)
if os.path.exists(baseline_file):
self.skipTest('Not capturing %s, its baseline image already exists. If you '
'want to capture this element again, delete %s'
% (file, baseline_file))
else:
save_baseline = True
if save_baseline:
# Save the baseline screenshot and bail out
element.get_screenshot().save(baseline_file)
return
else:
if not os.path.exists(baseline_file):
raise IOError('The baseline screenshot %s does not exist. '
'You might want to re-run this test in baseline-saving mode.'
% baseline_file)
# Save the new screenshot
element.get_screenshot().save(output_file)
try:
self.engine.assertSameFiles(output_file, baseline_file, threshold)
except:
raise
else:
if self.cleanup_on_success:
os.remove(output_file)
def assert_screenshot(self,
file_path,
element_or_selector=None,
threshold=0,
exclude=None):
"""Fail if new fresh image is too dissimilar from the baseline image
.. note:: From needle
https://github.com/python-needle/needle/blob/master/needle/cases.py#L161
:param str file_path: File name for baseline image
:param element_or_selector: WebElement or tuple containing selector ex. ('id', 'mainPage')
:param threshold: Distance threshold
:param list exclude: Elements or element selectors for areas to exclude
:return:
"""
element = self._find_element(element_or_selector)
# Get baseline image
if isinstance(file_path, basestring):
baseline_image = os.path.join(self.baseline_dir,
'%s.png' % file_path)
if self.save_baseline:
# Take screenshot and exit
return self.get_screenshot_as_image(
element, exclude=exclude).save(baseline_image)
else:
if not os.path.exists(baseline_image):
raise IOError(
'The baseline screenshot %s does not exist. '
'You might want to re-run this test in baseline-saving mode.'
% baseline_image)
else:
# Comparing in-memory files instead of on-disk files
baseline_image = Image.open(file_path).convert('RGB')
# Get fresh screenshot
fresh_image = self.get_screenshot_as_image(element, exclude=exclude)
# Compare images
if isinstance(baseline_image, basestring):
output_file = os.path.join(self.output_dir, '%s.png' % file_path)
fresh_image.save(output_file)
try:
self.engine.assertSameFiles(output_file, baseline_image,
threshold)
except AssertionError as err:
msg = err.message \
if hasattr(err, "message") \
else err.args[0] if err.args else ""
args = err.args[1:] if len(err.args) > 1 else []
raise ImageMismatchException(msg, baseline_image, output_file,
args)
finally:
if self.cleanup_on_success:
os.remove(output_file)
else:
diff = ImageDiff(fresh_image, baseline_image)
distance = abs(diff.get_distance())
if distance > threshold:
pytest.fail('Fail: New screenshot did not match the '
'baseline (by a distance of %.2f)' % distance)
