tests: extract shared mock grafana server from jellyfin test

tests/mock-grafana-server.py

@@ -0,0 +1,58 @@
+import http.server, json, sys
+
+PORT = int(sys.argv[1])
+DATA_FILE = sys.argv[2]
+
+class Handler(http.server.BaseHTTPRequestHandler):
+    def log_message(self, fmt, *args):
+        pass
+
+    def _read_body(self):
+        length = int(self.headers.get("Content-Length", 0))
+        return json.loads(self.rfile.read(length)) if length else {}
+
+    def _json(self, code, body):
+        data = json.dumps(body).encode()
+        self.send_response(code)
+        self.send_header("Content-Type", "application/json")
+        self.end_headers()
+        self.wfile.write(data)
+
+    def do_POST(self):
+        if self.path == "/api/annotations":
+            body = self._read_body()
+            try:
+                with open(DATA_FILE) as f:
+                    annotations = json.load(f)
+            except Exception:
+                annotations = []
+            aid = len(annotations) + 1
+            body["id"] = aid
+            annotations.append(body)
+            with open(DATA_FILE, "w") as f:
+                json.dump(annotations, f)
+            self._json(200, {"id": aid, "message": "Annotation added"})
+        else:
+            self.send_response(404)
+            self.end_headers()
+
+    def do_PATCH(self):
+        if self.path.startswith("/api/annotations/"):
+            aid = int(self.path.rsplit("/", 1)[-1])
+            body = self._read_body()
+            try:
+                with open(DATA_FILE) as f:
+                    annotations = json.load(f)
+            except Exception:
+                annotations = []
+            for a in annotations:
+                if a["id"] == aid:
+                    a.update(body)
+            with open(DATA_FILE, "w") as f:
+                json.dump(annotations, f)
+            self._json(200, {"message": "Annotation patched"})
+        else:
+            self.send_response(404)
+            self.end_headers()
+
+http.server.HTTPServer(("127.0.0.1", PORT), Handler).serve_forever()