python: Add basic openapi.json fetching test (#1647)

See
#1638 (comment).

python/requirements-dev.txt

@@ -1,5 +1,5 @@
 #
-# This file is autogenerated by pip-compile with Python 3.12
+# This file is autogenerated by pip-compile with Python 3.13
 # by the following command:
 #
 #    pip-compile --output-file=requirements-dev.txt requirements.in/development.txt
@@ -109,13 +109,17 @@ sniffio==1.3.1
     #   httpx
 typer==0.9.4
     # via openapi-python-client
+types-requests==2.32.0.20241016
+    # via -r requirements.in/development.txt
 typing-extensions==4.12.2
     # via
     #   mypy
     #   pydantic
     #   typer
 urllib3==2.2.3
-    # via requests
+    # via
+    #   requests
+    #   types-requests
 werkzeug==3.0.4
     # via pytest-httpserver
 wheel==0.44.0

python/requirements.in/development.txt

@@ -8,3 +8,4 @@ jinja2>=3.1.3
 pytest-docker
 pytest-httpserver
 requests
+types-requests

python/tests/test_openapi.py

@@ -0,0 +1,6 @@
+import requests
+
+def test_openapi_json_is_available(svix_server_url: str) -> None:
+    r = requests.get(f"{svix_server_url}/api/v1/openapi.json")
+    assert r.status_code == 200
+    assert r.headers["content-type"] == 'application/json'