Merge pull request #2 from matslindh/add-xpath-to-screenshot-regression-and-windows-compatibility-fix

feat: allow xpath for test regression against element + Windows support

Author: Apkawa

pytest_image_diff/splinter.py

@@ -1,3 +1,5 @@
+import os
+import pathlib
 import pytest
 from tempfile import NamedTemporaryFile
 from typing import Optional, Generator
@@ -19,6 +21,7 @@ def __call__(
             browser: Optional[Browser] = None,
             threshold: Optional[float] = None,
             suffix: Optional[str] = None,
+            xpath: Optional[str] = "",
         ) -> bool:
             pass
 
@@ -36,22 +39,46 @@ def screenshot_regression(
         :param browser: optional, by default from `browser` fixture
         :param threshold: float, by default from `image_diff_threshold`
         :param suffix: str, need for multiple checks  by one test
+        :param xpath: str, optional xpath expression to select an element to screenshot instead of page
         """
         default_browser = browser
 
         def _factory(
             browser: Optional[Browser] = None,
             threshold: Optional[float] = None,
             suffix: Optional[str] = "",
+            xpath: Optional[str] = "",
         ) -> bool:
             if browser is None:
                 browser = default_browser
 
             if threshold is None:
                 threshold = image_diff_threshold
-            tf = NamedTemporaryFile(suffix=".png")
-            image = tf.name
-            browser.driver.save_screenshot(image)
-            return image_regression(image, threshold, suffix)
+
+            with NamedTemporaryFile(suffix=".png", delete=False) as tf:
+                temp_image_path = pathlib.Path(tf.name)
+
+            try:
+                screenshot_path = os.fspath(temp_image_path)
+
+                if xpath:
+                    # `unique_file=False` since we already have a temporary file
+                    #
+                    # Since an xpath screenshot composes its own file name, we need to give it the prefix and
+                    # suffix as separate parameters. `:-4` for the path without extension, then suffix given manually.
+                    browser.find_by_xpath(xpath).first.screenshot(screenshot_path[:-4],
+                                                                  suffix=screenshot_path[-4:],
+                                                                  unique_file=False,
+                                                                  full=True,
+                                                                  )
+                else:
+                    browser.driver.save_screenshot(screenshot_path)
+
+                result = image_regression(screenshot_path, threshold, suffix)
+            finally:
+                temp_image_path.unlink(missing_ok=True)
+
+            return result
+
 
         yield _factory