[IMP] base: add test for wkhtmltopdf generation

The current used version of wkhtmltopdf manages is frozen to 0.12.5
because some features used by odoo are only available in this version
using a patched qt.

Anyway, it become difficult to keep this version up to date, especially
with Ubuntu Jammy and updates of the dependencies used by wkhtmltopdf.
More than that because of qt related issues, wkhtmltopdf maintenance
will end soon.

Adding a test to check some caracteristics of pdf reports may be usefull
to check that current version is still working, and eventually to find
an alternative solution.

This test checks that pdf reports contains the expected headers and
footers elements with the correct page number (2 record of 2 pages)
This also check that the pdf is in the expected A4 format.

Future test may check other formats, margins, layout,
page size/pagebreak combination, (table of content?), ...

This test may also check performances and existing limitations.

closes odoo/odoo#136626

Signed-off-by: Christophe Monniez (moc) <moc@odoo.com>

odoo/tests/common.py

@@ -866,6 +866,22 @@ def fchain(future, next_callback):
 
     return new_future
 
+
+def save_test_file(test_name, content, prefix, extension='png', logger=_logger, document_type='Screenshot'):
+    assert re.fullmatch(r'\w*_', prefix)
+    assert re.fullmatch(r'[a-z]+', extension)
+    assert re.fullmatch(r'\w+', test_name)
+    now = datetime.now().strftime("%Y%m%d_%H%M%S_%f")
+    screenshots_dir = pathlib.Path(odoo.tools.config['screenshots']) / get_db_name() / 'screenshots'
+    screenshots_dir.mkdir(parents=True, exist_ok=True)
+    fname = f'{prefix}{now}_{test_name}.{extension}'
+    full_path = screenshots_dir / fname
+
+    with full_path.open('wb') as f:
+        f.write(content)
+    logger.runbot(f'{document_type} in: {full_path}')
+
+
 class ChromeBrowser:
     """ Helper object to control a Chrome headless process. """
     remote_debugging_port = 0  # 9222, change it in a non-git-tracked file
@@ -879,9 +895,6 @@ class ChromeBrowser:
         self.user_data_dir = tempfile.mkdtemp(suffix='_chrome_odoo')
 
         otc = odoo.tools.config
-        self.screenshots_dir = os.path.join(otc['screenshots'], get_db_name(), 'screenshots')
-        os.makedirs(self.screenshots_dir, exist_ok=True)
-
         self.screencasts_dir = None
         self.screencast_frames = []
         if otc['screencasts']:
@@ -1331,21 +1344,14 @@ which leads to stray network requests and inconsistencies."""))
         # endGroup, assert, profile, profileEnd, count, timeEnd
     }
 
-    def take_screenshot(self, prefix='sc_', suffix=None):
+    def take_screenshot(self, prefix='sc_'):
         def handler(f):
             base_png = f.result(timeout=0)['data']
             if not base_png:
                 self._logger.warning("Couldn't capture screenshot: expected image data, got ?? error ??")
                 return
-
             decoded = base64.b64decode(base_png, validate=True)
-            fname = '{}{:%Y%m%d_%H%M%S_%f}{}.png'.format(
-                prefix, datetime.now(),
-                suffix or '_%s' % self.test_class.__name__)
-            full_path = os.path.join(self.screenshots_dir, fname)
-            with open(full_path, 'wb') as f:
-                f.write(decoded)
-            self._logger.runbot('Screenshot in: %s', full_path)
+            save_test_file(self.test_class.__name__, decoded, prefix, logger=self._logger)
 
         self._logger.info('Asking for screenshot')
         f = self._websocket_send('Page.captureScreenshot', with_future=True)