Module ez_visual_regression.api
Expand source code
# Standard lib dependencies
import os # Path verification & modification
import time # Allows for pauses
import logging # Enables logging
import webbrowser
from typing import Union, List
# Third Party Dependencies
## Image comparison
from ez_img_diff.api import compare_images
## Browser automation
from selenium import webdriver # Instantiates a browser
from selenium.webdriver.common.by import By # Specify find_element type
from selenium.webdriver.chrome.options import Options # Allows webdriver config
from selenium.webdriver.remote.webdriver import WebDriver # Used for type hinting
from selenium.common.exceptions import NoSuchElementException # Allows for error catching
### Used to manage driver installation
from webdriver_manager.chrome import ChromeDriverManager
from webdriver_manager.firefox import GeckoDriverManager
from webdriver_manager.microsoft import EdgeChromiumDriverManager
### Services needed for instantiating browsers
from selenium.webdriver.chrome.service import Service as ChromeService # Helps instantiate browser
from selenium.webdriver.edge.service import Service as EdgeService # Helps instantiate browser
from selenium.webdriver.firefox.service import Service as FirefoxService
def get_screenshot(driver:WebDriver, url:str, filename:str, locator:Union[str, None]=None, ignored_elements: List[str]= None):
"""Takes a screenshot of a page or element
Parameters
----------
driver : WebDriver
The browser to use for capturing screenshots
url : str
The URl you want to get a screenshot from (or filepath)
filename : str, optional
The file to export the screenshot to, by default None
locator : Union[str, None], optional
The CSS selector to search the element with (i.e. #myChart, .rows etc.)
ignored_elements: List[str], option
Use a query selector to specify elements to ignore
Notes
-----
- If locator is not specified a full page screenshot is used
References
----------
- How to use by if you've never seen it https://selenium-python.readthedocs.io/locating-elements.html
Raises
------
FileNotFoundError
If the URL is a file path and it does not exist
Examples
--------
### Create a screenshot of full page
```
from ez_visual_regression.api import get_screenshot, get_installed_driver, instantiate_driver
# Configuration variables
URL = "https://canadiancoding.ca"
filename = "screenshot.png"
driver_name = "chrome"
driver = instantiate_driver(driver_name)
get_screenshot(driver, URL, filename=filename)
```
### Create a screenshot of an element
```
from ez_visual_regression.api import get_screenshot, get_installed_driver, instantiate_driver
# Configuration variables
URL = "https://canadiancoding.ca"
filename = "screenshot.png"
driver_name = "chrome"
driver = instantiate_driver(driver_name)
locator = "#myChart"
get_screenshot(driver, URL, filename=filename, locator=locator)
```
### Create a screenshot of full page while ignoring elements with the card class and nav element(s)
```
from ez_visual_regression.api import get_screenshot, get_installed_driver, instantiate_driver
# Configuration variables
URL = "https://canadiancoding.ca"
filename = "screenshot.png"
driver_name = "chrome"
driver = instantiate_driver(driver_name)
ignored_elements = ["nav", ".card"]
get_screenshot(driver, URL, filename=filename, ignored_elements=ignored_elements)
```
"""
if not url.startswith("http"):
if (url.endswith(".html") or url.endswith(".pdf")) and not url.startswith("file:///"): # Assume file path
logging.debug("URL provided does not have protocol, defaulting to file")
abs_fp = os.path.abspath(url).replace("\\","/")
if not os.path.exists(abs_fp):
raise FileNotFoundError(f"File path {abs_fp} does not exist")
url = f"file:///{abs_fp}"
else:
url = "http://" + url
if not os.path.exists(os.path.dirname(filename)):
os.mkdir(os.path.dirname(filename))
print(f"{filename=} {locator=}")
driver.get(url)
# Wait for page to load and run all animations
time.sleep(3) # TODO: Be better
if ignored_elements:
for selector in ignored_elements:
driver.execute_script(f'document.querySelectorAll("{selector}").forEach((el)=>{{el.style.opacity=0}})')
if locator: # Screenshot element
try:
driver.find_elements(By.CSS_SELECTOR, locator)[0].screenshot(filename)
except NoSuchElementException:
logging.error(f"\033[0;m Element does not exist when looking for css selector: {locator} confirm spelling and capitalization\033[1;37m")
exit(1)
else: # Screenshot page
driver.save_screenshot(filename)
def compare_multiple_elements(driver:WebDriver, url:str, folder:str, locator:str, ignored_elements: List[str]= None) -> List[float]:
"""Regression test multiple elements
Parameters
----------
driver : WebDriver
The browser to use for capturing screenshots
url : str
The URl you want to get a screenshot from (or filepath)
folder : str
The folder to export the screenshots to
locator : str
The CSS selector to search the element with (i.e. #myChart, .rows etc.)
ignored_elements: List[str], option
Use a query selector to specify elements to ignore
Notes
-----
- If locator is not specified a full page screenshot is used
References
----------
- How to use by if you've never seen it https://selenium-python.readthedocs.io/locating-elements.html
Raises
------
FileNotFoundError
If the URL is a file path and it does not exist
Returns
-------
List[float]:
The differences of each found element
Examples
--------
### Compare multiple elements
```
from ez_visual_regression.api import compare_multiple_elements,instantiate_driver
# Configuration variables
URL = "https://canadiancoding.ca"
folder = "canadiancoding"
driver = instantiate_driver("chrome")
locator = ".nav-item p"
compare_multiple_elements(driver, URL,folder, locator) # Returns (assuming 3 total elements): [0.1, 19.8, 0.4]
```
### Compare multiple elements while ignoring divs and the red class
```
from ez_visual_regression.api import compare_multiple_elements,nstantiate_driver
# Configuration variables
URL = "https://canadiancoding.ca"
folder = "canadiancoding"
driver = instantiate_driver("chrome")
locator = ".nav-item p"
ignored_elements= ["div", ".red"]
compare_multiple_elements(driver, URL,folder, locator, ignored_elements) # Returns (assuming 3 total elements): [0.1, 0.0, 0.4]
```
"""
if not url.startswith("http"):
if (url.endswith(".html") or url.endswith(".pdf")) and not url.startswith("file:///"): # Assume file path
logging.debug("URL provided does not have protocol, defaulting to file")
abs_fp = os.path.abspath(url).replace("\\","/")
if not os.path.exists(abs_fp):
raise FileNotFoundError(f"File path {abs_fp} does not exist")
url = f"file:///{abs_fp}"
else:
url = "http://" + url
if not os.path.isdir(folder):
os.mkdir(folder)
driver.get(url)
# Wait for page to load and run all animations
time.sleep(3) # TODO: Be better
if ignored_elements:
for selector in ignored_elements:
driver.execute_script(f'document.querySelectorAll("{selector}").forEach((el)=>{{el.style.opacity=0}})')
try:
elements = driver.find_elements(By.CSS_SELECTOR, locator)
baseline_images = [(os.path.join(folder,f"baseline-{index}.png"), element) for index, element in enumerate(elements)]
current_images = [element for element in elements]
diffs = []
for path, element in baseline_images:
if not os.path.exists(path):
element.screenshot(path)
for index,element in enumerate(current_images):
element.screenshot(os.path.join(folder,f"current-{index}.png"))
diffs.append(compare_images(os.path.join(folder,f"current-{index}.png"), os.path.join(folder,f"baseline-{index}.png"), os.path.join(folder,f"diff-{index}.png"),os.path.join(folder,f"thresh-{index}.png")))
except NoSuchElementException:
logging.error(f"\033[0;m Element does not exist when looking for css selector: {locator} confirm spelling and capitalization\033[1;37m")
exit(1)
return diffs
def assert_image_similarity_to_baseline(driver:WebDriver, url:str, folder:str, locator:Union[str, None]=None, warning_threshold:float=10, error_threshold:float=30, ignored_elements: List[str]= None, multielements:bool=False) -> Union[float, List[float]]:
"""Asserts the current screenshot of a page is similar to `<folder>/baseline.png` within: 0 < diff < error_threshold
Parameters
----------
driver : WebDriver
The browser to use for capturing screenshots
url : str
The URl you want to get a screenshot from (or filepath)
folder : str
The folder to save the baseline, threshold, current and difference images to
locator : Union[str, None], optional
The CSS selector to search the element with (i.e. #myChart, .rows etc.)
warning_threshold : float, optional
The threshold at which there will be a logged warning, by default 10
error_threshold : float, optional
The threshold at which an explicit error will be thrown, by default 30
ignored_elements: List[str], option
Use a query selector to specify elements to ignore
multielements: bool, option
Whether to screenshot all occurances of a css selector (True), or just the firs occurance (False), default False
Raises
------
AssertionError
If diff > error_threshold
Returns
-------
Union[float, List[float]]:
The difference between the two images as a whole number percent (i.e. 1.313 is 1.313% or 15.928 is 15.928%), or list of floats if multielement is True
Examples
--------
### Create baseline images for a webpage
```
# Setup driver
from ez_visual_regression.api import instantiate_driver
driver_name = "chrome"
driver = instantiate_driver(driver_name)
# import functions needed for testing
from ez_visual_regression.api import assert_image_similarity_to_baseline
url = "tests/example_sites/no_difference/index.html" # File in this case
folder = "tests/example_sites/no_difference" # Where to store output images
locator = "#myChart" # The queryselector to find an element with
# Creates baseline if one isn't available
assert_image_similarity_to_baseline(driver,url, locator=locator, folder=folder)
```
### Test against baseline image
```
# Setup driver
from ez_visual_regression.api import instantiate_driver
driver_name = "chrome"
driver = instantiate_driver(driver_name)
# import functions needed for testing
from ez_visual_regression.api import assert_image_similarity_to_baseline
url = "tests/example_sites/no_difference/index.html" # File in this case
folder = "tests/example_sites/no_difference" # Where to store output images
locator = "#myChart" # The queryselector to find an element with
try:
assert_image_similarity_to_baseline(driver,url, locator=locator, folder=folder )
except AssertionError:
print("Image too far from baseline!")
```
### Take screenshot of whole page while ignoring h2's and elements with id of myChart
```
# Setup driver
from ez_visual_regression.api import instantiate_driver
driver_name = "chrome"
driver = instantiate_driver(driver_name)
# import functions needed for testing
from ez_visual_regression.api import assert_image_similarity_to_baseline
url = "tests/example_sites/no_difference/index.html" # File in this case
folder = "tests/example_sites/no_difference" # Where to store output images
ignored_elements = ["h2", "#myChart"]
assert_image_similarity_to_baseline(driver,url, folder=folder, ignored_elements=ignored_elements)
```
### Take screenshot of all nav elements (not just 1) on a page
```
from ez_visual_regression.api import compare_multiple_elements, instantiate_driver
# Configuration variables
URL = "https://canadiancoding.ca"
folder = "canadiancoding"
driver = instantiate_driver("chrome")
locator = ".nav-item p"
ignored_elements= ["div", ".red"]
assert_image_similarity_to_baseline(driver, URL, folder, locator, ignored_elements=ignored_elements, multielements=True) # Returns (assuming 3 total elements): [0.1, 0.0, 0.4]
```
"""
if not os.path.isdir(folder):
print(f"No directory was found called {folder}, creating...")
os.mkdir(folder)
if not os.path.exists(os.path.join(folder, "baseline.png")) and not multielements:
print(f"No baseline image(s) found in {os.path.join(folder, 'baseline.png')}, creating...")
get_screenshot(driver, url, os.path.join(folder, "baseline.png"), locator, ignored_elements)
if multielements:
diffs = compare_multiple_elements(driver, url, folder, locator, ignored_elements)
return diffs
else:
get_screenshot(driver, url, os.path.join(folder, "current.png"), locator, ignored_elements)
diff = compare_images(os.path.join(folder, "baseline.png"), os.path.join(folder, "current.png"), os.path.join(folder, "diff.png"), os.path.join(folder, "thresh.png"))
if diff > error_threshold:
logging.error(f"Difference {diff} is over error threshold {error_threshold}")
raise AssertionError(f"Difference {diff} is over error threshold {error_threshold}")
if error_threshold > diff > warning_threshold:
logging.warning(f"Difference {diff} is over warning threshold {error_threshold}")
return diff
def instantiate_driver(driver:str) -> WebDriver:
"""Creates a webdriver based on a driver name
Parameters
----------
driver : str
The name of the driver to use (can be "edge", "chrome" or "firefox")
Returns
-------
WebDriver
The webdriver for the specified browser
Raises
------
ValueError
If the driver does not exist
Examples
--------
### Get any supported browser, and instantiate it
```
from ez_visual_regression.api import instantiate_driver
driver_name = "chrome" # Either "chrome", "firefox","edge" or raises webbrowser.Error
instantiate_driver(driver_name) # Returns a WebDriver of the correct browser type
```
### Check if person has chrome installed
```
from ez_visual_regression.api import instantiate_driver
get_installed_driver("chrome") # Either "chrome" or raises webbrowser.Error
instantiate_driver(driver_name) # Returns a Chrome.WebDriver
```
"""
if driver == "chrome":
chrome_options = Options()
chrome_options.add_argument("--disable-gpu")
chrome_options.add_argument("--no-sandbox")
return webdriver.Chrome(options=chrome_options, service=ChromeService(ChromeDriverManager().install()))
elif driver == "edge":
edge_options = Options()
return webdriver.Edge(options=edge_options, service=EdgeService(EdgeChromiumDriverManager().install()))
elif driver == "firefox":
return webdriver.Firefox(service=FirefoxService(GeckoDriverManager().install()))
else:
raise ValueError(f"Driver not supported {driver}")Functions
def assert_image_similarity_to_baseline(driver: selenium.webdriver.remote.webdriver.WebDriver, url: str, folder: str, locator: Optional[str] = None, warning_threshold: float = 10, error_threshold: float = 30, ignored_elements: List[str] = None, multielements: bool = False) ‑> Union[float, List[float]]-
Asserts the current screenshot of a page is similar to
<folder>/baseline.pngwithin: 0 < diff < error_thresholdParameters
driver:WebDriver- The browser to use for capturing screenshots
url:str- The URl you want to get a screenshot from (or filepath)
folder:str- The folder to save the baseline, threshold, current and difference images to
locator:Union[str, None], optional- The CSS selector to search the element with (i.e. #myChart, .rows etc.)
warning_threshold:float, optional- The threshold at which there will be a logged warning, by default 10
error_threshold:float, optional- The threshold at which an explicit error will be thrown, by default 30
ignored_elements:List[str], option- Use a query selector to specify elements to ignore
multielements:bool, option- Whether to screenshot all occurances of a css selector (True), or just the firs occurance (False), default False
Raises
AssertionError- If diff > error_threshold
Returns
Union[float, List[float]]:- The difference between the two images as a whole number percent (i.e. 1.313 is 1.313% or 15.928 is 15.928%), or list of floats if multielement is True
Examples
Create baseline images for a webpage
# Setup driver from ez_visual_regression.api import instantiate_driver driver_name = "chrome" driver = instantiate_driver(driver_name) # import functions needed for testing from ez_visual_regression.api import assert_image_similarity_to_baseline url = "tests/example_sites/no_difference/index.html" # File in this case folder = "tests/example_sites/no_difference" # Where to store output images locator = "#myChart" # The queryselector to find an element with # Creates baseline if one isn't available assert_image_similarity_to_baseline(driver,url, locator=locator, folder=folder)Test against baseline image
# Setup driver from ez_visual_regression.api import instantiate_driver driver_name = "chrome" driver = instantiate_driver(driver_name) # import functions needed for testing from ez_visual_regression.api import assert_image_similarity_to_baseline url = "tests/example_sites/no_difference/index.html" # File in this case folder = "tests/example_sites/no_difference" # Where to store output images locator = "#myChart" # The queryselector to find an element with try: assert_image_similarity_to_baseline(driver,url, locator=locator, folder=folder ) except AssertionError: print("Image too far from baseline!")Take screenshot of whole page while ignoring h2's and elements with id of myChart
# Setup driver from ez_visual_regression.api import instantiate_driver driver_name = "chrome" driver = instantiate_driver(driver_name) # import functions needed for testing from ez_visual_regression.api import assert_image_similarity_to_baseline url = "tests/example_sites/no_difference/index.html" # File in this case folder = "tests/example_sites/no_difference" # Where to store output images ignored_elements = ["h2", "#myChart"] assert_image_similarity_to_baseline(driver,url, folder=folder, ignored_elements=ignored_elements)Take screenshot of all nav elements (not just 1) on a page
from ez_visual_regression.api import compare_multiple_elements, instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" folder = "canadiancoding" driver = instantiate_driver("chrome") locator = ".nav-item p" ignored_elements= ["div", ".red"] assert_image_similarity_to_baseline(driver, URL, folder, locator, ignored_elements=ignored_elements, multielements=True) # Returns (assuming 3 total elements): [0.1, 0.0, 0.4]Expand source code
def assert_image_similarity_to_baseline(driver:WebDriver, url:str, folder:str, locator:Union[str, None]=None, warning_threshold:float=10, error_threshold:float=30, ignored_elements: List[str]= None, multielements:bool=False) -> Union[float, List[float]]: """Asserts the current screenshot of a page is similar to `<folder>/baseline.png` within: 0 < diff < error_threshold Parameters ---------- driver : WebDriver The browser to use for capturing screenshots url : str The URl you want to get a screenshot from (or filepath) folder : str The folder to save the baseline, threshold, current and difference images to locator : Union[str, None], optional The CSS selector to search the element with (i.e. #myChart, .rows etc.) warning_threshold : float, optional The threshold at which there will be a logged warning, by default 10 error_threshold : float, optional The threshold at which an explicit error will be thrown, by default 30 ignored_elements: List[str], option Use a query selector to specify elements to ignore multielements: bool, option Whether to screenshot all occurances of a css selector (True), or just the firs occurance (False), default False Raises ------ AssertionError If diff > error_threshold Returns ------- Union[float, List[float]]: The difference between the two images as a whole number percent (i.e. 1.313 is 1.313% or 15.928 is 15.928%), or list of floats if multielement is True Examples -------- ### Create baseline images for a webpage ``` # Setup driver from ez_visual_regression.api import instantiate_driver driver_name = "chrome" driver = instantiate_driver(driver_name) # import functions needed for testing from ez_visual_regression.api import assert_image_similarity_to_baseline url = "tests/example_sites/no_difference/index.html" # File in this case folder = "tests/example_sites/no_difference" # Where to store output images locator = "#myChart" # The queryselector to find an element with # Creates baseline if one isn't available assert_image_similarity_to_baseline(driver,url, locator=locator, folder=folder) ``` ### Test against baseline image ``` # Setup driver from ez_visual_regression.api import instantiate_driver driver_name = "chrome" driver = instantiate_driver(driver_name) # import functions needed for testing from ez_visual_regression.api import assert_image_similarity_to_baseline url = "tests/example_sites/no_difference/index.html" # File in this case folder = "tests/example_sites/no_difference" # Where to store output images locator = "#myChart" # The queryselector to find an element with try: assert_image_similarity_to_baseline(driver,url, locator=locator, folder=folder ) except AssertionError: print("Image too far from baseline!") ``` ### Take screenshot of whole page while ignoring h2's and elements with id of myChart ``` # Setup driver from ez_visual_regression.api import instantiate_driver driver_name = "chrome" driver = instantiate_driver(driver_name) # import functions needed for testing from ez_visual_regression.api import assert_image_similarity_to_baseline url = "tests/example_sites/no_difference/index.html" # File in this case folder = "tests/example_sites/no_difference" # Where to store output images ignored_elements = ["h2", "#myChart"] assert_image_similarity_to_baseline(driver,url, folder=folder, ignored_elements=ignored_elements) ``` ### Take screenshot of all nav elements (not just 1) on a page ``` from ez_visual_regression.api import compare_multiple_elements, instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" folder = "canadiancoding" driver = instantiate_driver("chrome") locator = ".nav-item p" ignored_elements= ["div", ".red"] assert_image_similarity_to_baseline(driver, URL, folder, locator, ignored_elements=ignored_elements, multielements=True) # Returns (assuming 3 total elements): [0.1, 0.0, 0.4] ``` """ if not os.path.isdir(folder): print(f"No directory was found called {folder}, creating...") os.mkdir(folder) if not os.path.exists(os.path.join(folder, "baseline.png")) and not multielements: print(f"No baseline image(s) found in {os.path.join(folder, 'baseline.png')}, creating...") get_screenshot(driver, url, os.path.join(folder, "baseline.png"), locator, ignored_elements) if multielements: diffs = compare_multiple_elements(driver, url, folder, locator, ignored_elements) return diffs else: get_screenshot(driver, url, os.path.join(folder, "current.png"), locator, ignored_elements) diff = compare_images(os.path.join(folder, "baseline.png"), os.path.join(folder, "current.png"), os.path.join(folder, "diff.png"), os.path.join(folder, "thresh.png")) if diff > error_threshold: logging.error(f"Difference {diff} is over error threshold {error_threshold}") raise AssertionError(f"Difference {diff} is over error threshold {error_threshold}") if error_threshold > diff > warning_threshold: logging.warning(f"Difference {diff} is over warning threshold {error_threshold}") return diff def compare_multiple_elements(driver: selenium.webdriver.remote.webdriver.WebDriver, url: str, folder: str, locator: str, ignored_elements: List[str] = None) ‑> List[float]-
Regression test multiple elements
Parameters
driver:WebDriver- The browser to use for capturing screenshots
url:str- The URl you want to get a screenshot from (or filepath)
folder:str- The folder to export the screenshots to
locator:str- The CSS selector to search the element with (i.e. #myChart, .rows etc.)
ignored_elements:List[str], option- Use a query selector to specify elements to ignore
Notes
- If locator is not specified a full page screenshot is used
References
- How to use by if you've never seen it https://selenium-python.readthedocs.io/locating-elements.html
Raises
FileNotFoundError- If the URL is a file path and it does not exist
Returns
List[float]:- The differences of each found element
Examples
Compare multiple elements
from ez_visual_regression.api import compare_multiple_elements,instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" folder = "canadiancoding" driver = instantiate_driver("chrome") locator = ".nav-item p" compare_multiple_elements(driver, URL,folder, locator) # Returns (assuming 3 total elements): [0.1, 19.8, 0.4]Compare multiple elements while ignoring divs and the red class
from ez_visual_regression.api import compare_multiple_elements,nstantiate_driver # Configuration variables URL = "https://canadiancoding.ca" folder = "canadiancoding" driver = instantiate_driver("chrome") locator = ".nav-item p" ignored_elements= ["div", ".red"] compare_multiple_elements(driver, URL,folder, locator, ignored_elements) # Returns (assuming 3 total elements): [0.1, 0.0, 0.4]Expand source code
def compare_multiple_elements(driver:WebDriver, url:str, folder:str, locator:str, ignored_elements: List[str]= None) -> List[float]: """Regression test multiple elements Parameters ---------- driver : WebDriver The browser to use for capturing screenshots url : str The URl you want to get a screenshot from (or filepath) folder : str The folder to export the screenshots to locator : str The CSS selector to search the element with (i.e. #myChart, .rows etc.) ignored_elements: List[str], option Use a query selector to specify elements to ignore Notes ----- - If locator is not specified a full page screenshot is used References ---------- - How to use by if you've never seen it https://selenium-python.readthedocs.io/locating-elements.html Raises ------ FileNotFoundError If the URL is a file path and it does not exist Returns ------- List[float]: The differences of each found element Examples -------- ### Compare multiple elements ``` from ez_visual_regression.api import compare_multiple_elements,instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" folder = "canadiancoding" driver = instantiate_driver("chrome") locator = ".nav-item p" compare_multiple_elements(driver, URL,folder, locator) # Returns (assuming 3 total elements): [0.1, 19.8, 0.4] ``` ### Compare multiple elements while ignoring divs and the red class ``` from ez_visual_regression.api import compare_multiple_elements,nstantiate_driver # Configuration variables URL = "https://canadiancoding.ca" folder = "canadiancoding" driver = instantiate_driver("chrome") locator = ".nav-item p" ignored_elements= ["div", ".red"] compare_multiple_elements(driver, URL,folder, locator, ignored_elements) # Returns (assuming 3 total elements): [0.1, 0.0, 0.4] ``` """ if not url.startswith("http"): if (url.endswith(".html") or url.endswith(".pdf")) and not url.startswith("file:///"): # Assume file path logging.debug("URL provided does not have protocol, defaulting to file") abs_fp = os.path.abspath(url).replace("\\","/") if not os.path.exists(abs_fp): raise FileNotFoundError(f"File path {abs_fp} does not exist") url = f"file:///{abs_fp}" else: url = "http://" + url if not os.path.isdir(folder): os.mkdir(folder) driver.get(url) # Wait for page to load and run all animations time.sleep(3) # TODO: Be better if ignored_elements: for selector in ignored_elements: driver.execute_script(f'document.querySelectorAll("{selector}").forEach((el)=>{{el.style.opacity=0}})') try: elements = driver.find_elements(By.CSS_SELECTOR, locator) baseline_images = [(os.path.join(folder,f"baseline-{index}.png"), element) for index, element in enumerate(elements)] current_images = [element for element in elements] diffs = [] for path, element in baseline_images: if not os.path.exists(path): element.screenshot(path) for index,element in enumerate(current_images): element.screenshot(os.path.join(folder,f"current-{index}.png")) diffs.append(compare_images(os.path.join(folder,f"current-{index}.png"), os.path.join(folder,f"baseline-{index}.png"), os.path.join(folder,f"diff-{index}.png"),os.path.join(folder,f"thresh-{index}.png"))) except NoSuchElementException: logging.error(f"\033[0;m Element does not exist when looking for css selector: {locator} confirm spelling and capitalization\033[1;37m") exit(1) return diffs def get_screenshot(driver: selenium.webdriver.remote.webdriver.WebDriver, url: str, filename: str, locator: Optional[str] = None, ignored_elements: List[str] = None)-
Takes a screenshot of a page or element
Parameters
driver:WebDriver- The browser to use for capturing screenshots
url:str- The URl you want to get a screenshot from (or filepath)
filename:str, optional- The file to export the screenshot to, by default None
locator:Union[str, None], optional- The CSS selector to search the element with (i.e. #myChart, .rows etc.)
ignored_elements:List[str], option- Use a query selector to specify elements to ignore
Notes
- If locator is not specified a full page screenshot is used
References
- How to use by if you've never seen it https://selenium-python.readthedocs.io/locating-elements.html
Raises
FileNotFoundError- If the URL is a file path and it does not exist
Examples
Create a screenshot of full page
from ez_visual_regression.api import get_screenshot, get_installed_driver, instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" filename = "screenshot.png" driver_name = "chrome" driver = instantiate_driver(driver_name) get_screenshot(driver, URL, filename=filename)Create a screenshot of an element
from ez_visual_regression.api import get_screenshot, get_installed_driver, instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" filename = "screenshot.png" driver_name = "chrome" driver = instantiate_driver(driver_name) locator = "#myChart" get_screenshot(driver, URL, filename=filename, locator=locator)Create a screenshot of full page while ignoring elements with the card class and nav element(s)
from ez_visual_regression.api import get_screenshot, get_installed_driver, instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" filename = "screenshot.png" driver_name = "chrome" driver = instantiate_driver(driver_name) ignored_elements = ["nav", ".card"] get_screenshot(driver, URL, filename=filename, ignored_elements=ignored_elements)Expand source code
def get_screenshot(driver:WebDriver, url:str, filename:str, locator:Union[str, None]=None, ignored_elements: List[str]= None): """Takes a screenshot of a page or element Parameters ---------- driver : WebDriver The browser to use for capturing screenshots url : str The URl you want to get a screenshot from (or filepath) filename : str, optional The file to export the screenshot to, by default None locator : Union[str, None], optional The CSS selector to search the element with (i.e. #myChart, .rows etc.) ignored_elements: List[str], option Use a query selector to specify elements to ignore Notes ----- - If locator is not specified a full page screenshot is used References ---------- - How to use by if you've never seen it https://selenium-python.readthedocs.io/locating-elements.html Raises ------ FileNotFoundError If the URL is a file path and it does not exist Examples -------- ### Create a screenshot of full page ``` from ez_visual_regression.api import get_screenshot, get_installed_driver, instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" filename = "screenshot.png" driver_name = "chrome" driver = instantiate_driver(driver_name) get_screenshot(driver, URL, filename=filename) ``` ### Create a screenshot of an element ``` from ez_visual_regression.api import get_screenshot, get_installed_driver, instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" filename = "screenshot.png" driver_name = "chrome" driver = instantiate_driver(driver_name) locator = "#myChart" get_screenshot(driver, URL, filename=filename, locator=locator) ``` ### Create a screenshot of full page while ignoring elements with the card class and nav element(s) ``` from ez_visual_regression.api import get_screenshot, get_installed_driver, instantiate_driver # Configuration variables URL = "https://canadiancoding.ca" filename = "screenshot.png" driver_name = "chrome" driver = instantiate_driver(driver_name) ignored_elements = ["nav", ".card"] get_screenshot(driver, URL, filename=filename, ignored_elements=ignored_elements) ``` """ if not url.startswith("http"): if (url.endswith(".html") or url.endswith(".pdf")) and not url.startswith("file:///"): # Assume file path logging.debug("URL provided does not have protocol, defaulting to file") abs_fp = os.path.abspath(url).replace("\\","/") if not os.path.exists(abs_fp): raise FileNotFoundError(f"File path {abs_fp} does not exist") url = f"file:///{abs_fp}" else: url = "http://" + url if not os.path.exists(os.path.dirname(filename)): os.mkdir(os.path.dirname(filename)) print(f"{filename=} {locator=}") driver.get(url) # Wait for page to load and run all animations time.sleep(3) # TODO: Be better if ignored_elements: for selector in ignored_elements: driver.execute_script(f'document.querySelectorAll("{selector}").forEach((el)=>{{el.style.opacity=0}})') if locator: # Screenshot element try: driver.find_elements(By.CSS_SELECTOR, locator)[0].screenshot(filename) except NoSuchElementException: logging.error(f"\033[0;m Element does not exist when looking for css selector: {locator} confirm spelling and capitalization\033[1;37m") exit(1) else: # Screenshot page driver.save_screenshot(filename) def instantiate_driver(driver: str) ‑> selenium.webdriver.remote.webdriver.WebDriver-
Creates a webdriver based on a driver name
Parameters
driver:str- The name of the driver to use (can be "edge", "chrome" or "firefox")
Returns
WebDriver- The webdriver for the specified browser
Raises
ValueError- If the driver does not exist
Examples
Get any supported browser, and instantiate it
from ez_visual_regression.api import instantiate_driver driver_name = "chrome" # Either "chrome", "firefox","edge" or raises webbrowser.Error instantiate_driver(driver_name) # Returns a WebDriver of the correct browser typeCheck if person has chrome installed
from ez_visual_regression.api import instantiate_driver get_installed_driver("chrome") # Either "chrome" or raises webbrowser.Error instantiate_driver(driver_name) # Returns a Chrome.WebDriverExpand source code
def instantiate_driver(driver:str) -> WebDriver: """Creates a webdriver based on a driver name Parameters ---------- driver : str The name of the driver to use (can be "edge", "chrome" or "firefox") Returns ------- WebDriver The webdriver for the specified browser Raises ------ ValueError If the driver does not exist Examples -------- ### Get any supported browser, and instantiate it ``` from ez_visual_regression.api import instantiate_driver driver_name = "chrome" # Either "chrome", "firefox","edge" or raises webbrowser.Error instantiate_driver(driver_name) # Returns a WebDriver of the correct browser type ``` ### Check if person has chrome installed ``` from ez_visual_regression.api import instantiate_driver get_installed_driver("chrome") # Either "chrome" or raises webbrowser.Error instantiate_driver(driver_name) # Returns a Chrome.WebDriver ``` """ if driver == "chrome": chrome_options = Options() chrome_options.add_argument("--disable-gpu") chrome_options.add_argument("--no-sandbox") return webdriver.Chrome(options=chrome_options, service=ChromeService(ChromeDriverManager().install())) elif driver == "edge": edge_options = Options() return webdriver.Edge(options=edge_options, service=EdgeService(EdgeChromiumDriverManager().install())) elif driver == "firefox": return webdriver.Firefox(service=FirefoxService(GeckoDriverManager().install())) else: raise ValueError(f"Driver not supported {driver}")