Python: Add test for missing data-flow step in aiohttp.web

python/ql/test/library-tests/frameworks/aiohttp/app_conf_test.py

@@ -0,0 +1,48 @@
+"""
+This file is a test of an extra data-flow step that we want to have for
+aiohttp.web.Application
+
+We don't really have an established way to test extra data-flow steps in external
+libraries right now, so for now I've just used our normal taint-flow testing ¯\_(ツ)_/¯
+
+see https://docs.aiohttp.org/en/stable/web_advanced.html#application-s-config
+"""
+
+from aiohttp import web
+
+# to make code runable
+TAINTED_STRING = "TAINTED_STRING"
+def ensure_tainted(*args, **kwargs):
+    pass
+
+ensure_tainted(
+    TAINTED_STRING # $ tainted
+)
+
+
+async def example(request: web.Request): # $ requestHandler
+    return web.Response(text=f'example {request.app["foo"]=}') # $ HttpResponse
+
+
+async def also_works(request: web.Request): # $ requestHandler
+    return web.Response(text=f'also_works {request.config_dict["foo"]=}') # $ HttpResponse
+
+
+async def taint_test(request: web.Request): # $ requestHandler
+    ensure_tainted(
+        request.app["ts"], # $ MISSING: tainted
+        request.config_dict["ts"], # $ MISSING: tainted
+    )
+    return web.Response(text="ok") # $ HttpResponse
+
+
+app = web.Application()
+app.router.add_get("", example) # $ routeSetup=""
+app.router.add_get("/also-works", also_works) # $ routeSetup="/also-works"
+app.router.add_get("/taint-test", taint_test) # $ routeSetup="/taint-test"
+app["foo"] = 42
+app["ts"] = TAINTED_STRING
+
+
+if __name__ == "__main__":
+    web.run_app(app)