tools: Add script to trigger webhook notification using fixtures.

When creating a webhook integration or creating a new one, it is a pain to
create or update the screenshots in the documentation. This commit adds a
tool that can trigger a sample notification for the webhook using a fixture,
that is likely already written for the tests.

Currently, the developer needs to take a screenshot manually, but this could
be automated using puppeteer or something like that.

Also, the tool does not support webhooks with basic auth, and only supports
webhooks that use json fixtures. These can be fixed in subsequent commits.

tools/setup/generate_zulip_bots_static_files.py

@@ -4,7 +4,10 @@ import glob
 import os
 import sys
 import shutil
-from typing import List
+import tempfile
+from typing import List, Optional
+
+import cairosvg
 
 ZULIP_PATH = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 if ZULIP_PATH not in sys.path:
@@ -42,5 +45,13 @@ def generate_zulip_bots_static_files() -> None:
     docs = glob.glob(doc_glob_pattern)
     copyfiles(docs)
 
+def create_png_from_svg(svg_path: str, destination_dir: Optional[str]=None) -> str:
+    png_name = os.path.splitext(os.path.basename(svg_path))[0] + '.png'
+    if destination_dir is None:
+        destination_dir = tempfile.gettempdir()
+    png_path = os.path.join(destination_dir, png_name)
+    cairosvg.svg2png(url=svg_path, write_to=png_path)
+    return png_path
+
 if __name__ == "__main__":
     generate_zulip_bots_static_files()