feat(tessie): add set_roles command for payer role assignment

docs/tessie.md

@@ -415,6 +415,9 @@ async def main():
         response = await vehicle.delete_driver(id=1)
         print(response)
 
+        response = await vehicle.set_roles(role="SUBSCRIPTION", account_id="555555555")
+        print(response)
+
         response = await vehicle.get_fleet_telemetry_config()
         print(response)
 

tesla_fleet_api/tessie/vehicle.py

@@ -1080,6 +1080,20 @@ async def revoke_invitation(self, id: str | int) -> dict[str, Any]:
             f"{self.vin}/invitations/{id}/revoke",
         )
 
+    async def set_roles(
+        self,
+        role: str,
+        account_id: str | None = None,
+        federation_id: str | None = None,
+    ) -> dict[str, Any]:
+        """Assign the subscription or charging payer role (requires a Tesla Business account)."""
+        payload: dict[str, str] = {"role": role}
+        if account_id is not None:
+            payload["account_id"] = account_id
+        if federation_id is not None:
+            payload["federation_id"] = federation_id
+        return await self._request(Method.POST, f"{self.vin}/roles", json=payload)
+
     # Fleet Telemetry
     async def get_fleet_telemetry_config(self) -> dict[str, Any]:
         """Retrieve telemetry configuration."""

tests/test_tessie_vehicle_params.py

@@ -250,7 +250,40 @@ async def test_tessie_add_charge_schedule_validates_enabled_times(self) -> None:
                 lon=4.56,
             )
 
-    async def test_tessie_add_precondition_schedule_uses_documented_parameters(self) -> None:
+    async def test_set_roles_uses_documented_parameters(self) -> None:
+        """set_roles should send the documented JSON body with only provided fields."""
+
+        vehicle, request = self.create_vehicle()
+
+        response = await vehicle.set_roles(
+            role="SUBSCRIPTION",
+            account_id="555555555",
+        )
+
+        self.assertEqual(response, {"result": True})
+        request.assert_awaited_once_with(
+            Method.POST,
+            f"{self.VIN}/roles",
+            json={"role": "SUBSCRIPTION", "account_id": "555555555"},
+        )
+
+    async def test_set_roles_omits_unset_optional_fields(self) -> None:
+        """set_roles should omit account_id/federation_id when not provided."""
+
+        vehicle, request = self.create_vehicle()
+
+        response = await vehicle.set_roles(role="CHARGING")
+
+        self.assertEqual(response, {"result": True})
+        request.assert_awaited_once_with(
+            Method.POST,
+            f"{self.VIN}/roles",
+            json={"role": "CHARGING"},
+        )
+
+    async def test_tessie_add_precondition_schedule_uses_documented_parameters(
+        self,
+    ) -> None:
         """Precondition schedule requests should follow the Tessie schema."""
 
         vehicle, request = self.create_vehicle()