Here are the tests for the `__add_route_to_vpc` method:
```less
@pytest.mark.asyncio
async def test_add_route_to_vpc_success(xaas_service):
    tenant_id = "tenant-1"
    vpc_id = "vpc-1"
    project_type = "xaas"
    target_subnet_cidr = "10.0.0.0/24"
    next_hop = "192.168.0.1"
    request_id = "req-1"

    await xaas_service._XAASService__add_route_to_vpc(tenant_id, vpc_id, project_type, target_subnet_cidr, next_hop, request_id)

    xaas_service.network_client.vpcs.add_route_to_vpc.assert_called_once_with(
        tenant_id=tenant_id,
        vpc_id=vpc_id,
        project_type=project_type,
        destination=target_subnet_cidr,
        next_hop=next_hop,
        request_id=request_id,
    )
@pytest.mark.asyncio
async def test_add_route_to_vpc_not_found(xaas_service):
    tenant_id = "tenant-1"
    vpc_id = "vpc-1"
    project_type = "xaas"
    target_subnet_cidr = "10.0.0.0/24"
    next_hop = "192.168.0.1"
    request_id = "req-1"

    xaas_service.network_client.vpcs.add_route_to_vpc.side_effect = NotFound()

    with pytest.raises(NotFoundException):
        await xaas_service._XAASService__add_route_to_vpc(tenant_id, vpc_id, project_type, target_subnet_cidr, next_hop, request_id)

    xaas_service.network_client.vpcs.add_route_to_vpc.assert_called_once_with(
        tenant_id=tenant_id,
        vpc_id=vpc_id,
        project_type=project_type,
        destination=target_subnet_cidr,
        next_hop=next_hop,
        request_id=request_id,
    )
@pytest.mark.asyncio
async def test_add_route_to_vpc_already_exists(xaas_service):
    tenant_id = "tenant-1"
    vpc_id = "vpc-1"
    project_type = "xaas"
    target_subnet_cidr = "10.0.0.0/24"
    next_hop = "192.168.0.1"
    request_id = "req-1"

    xaas_service.network_client.vpcs.add_route_to_vpc.side_effect = KeyConflict()

    xaas_service._logger = MagicMock()

    await xaas_service._XAASService__add_route_to_vpc(tenant_id, vpc_id, project_type, target_subnet_cidr, next_hop, request_id)

    xaas_service.network_client.vpcs.add_route_to_vpc.assert_called_once_with(
        tenant_id=tenant_id,
        vpc_id=vpc_id,
        project_type=project_type,
        destination=target_subnet_cidr,
        next_hop=next_hop,
        request_id=request_id,
    )

    xaas_service._logger.warning.assert_called_once_with(
        f"Route ({target_subnet_cidr}, {next_hop}) already exists"
    )
@pytest.mark.asyncio
async def test_add_route_to_vpc_internal_error(xaas_service):
    tenant_id = "tenant-1"
    vpc_id = "vpc-1"
    project_type = "xaas"
    target_subnet_cidr = "10.0.0.0/24"
    next_hop = "192.168.0.1"
    request_id = "req-1"

    xaas_service.network_client.vpcs.add_route_to_vpc.side_effect = Exception()

    with pytest
```
다음은 `__add_route_to_vpc` 메서드에 대한 테스트입니다:```less@pytest.mark.asyncioasync def test_add_route_to_vpc_success(xaas_service):    tenant_id = "tenant-1"    vpc_id = "vpc-1"    project_type = "xaas"    target_subnet_cidr = "10.0.0.0/24"    next_hop = "192.168.0.1"    request_id = "req-1"    await xaas_service._XAASService__add_route_to_vpc(tenant_id, vpc_id, project_type, target_subnet_cidr, next_hop, request_id)    xaas_service.network_client.vpcs.add_route_to_vpc.assert_called_once_with(        테넌트_ID=테넌트_ID,        vpc_id=vpc_id,        project_type=프로젝트_type,        대상=대상_서브넷_시드르,        next_hop=next_hop,        요청_ID=요청_ID,    )@pytest.mark.asyncioasync def test_add_route_to_vpc_not_found(xaas_service):    tenant_id = "tenant-1"    vpc_id = "vpc-1"    project_type = "xaas"    target_subnet_cidr = "10.0.0.0/24"    next_hop = "192.168.0.1"    request_id = "req-1"    xaas_service.network_client.vpcs.add_route_to_vpc.side_effect = NotFound()    와 함께 pytest.raises(NotFoundException):        await xaas_service._XAASService__add_route_to_vpc(tenant_id, vpc_id, project_type, target_subnet_cidr, next_hop, request_id)    xaas_service.network_client.vpcs.add_route_to_vpc.assert_called_once_with(        테넌트_ID=테넌트_ID,        vpc_id=vpc_id,        project_type=프로젝트_type,        대상=대상_서브넷_시드르,        next_hop=next_hop,        요청_ID=요청_ID,    )@pytest.mark.asyncioasync def test_add_route_to_vpc_already_exists(xaas_service):    tenant_id = "tenant-1"    vpc_id = "vpc-1"    project_type = "xaas"    target_subnet_cidr = "10.0.0.0/24"    next_hop = "192.168.0.1"    request_id = "req-1"    xaas_service.network_client.vpcs.add_route_to_vpc.side_effect = KeyConflict()    xaas_service._logger = MagicMock()    await xaas_service._XAASService__add_route_to_vpc(tenant_id, vpc_id, project_type, target_subnet_cidr, next_hop, request_id)    xaas_service.network_client.vpcs.add_route_to_vpc.assert_called_once_with(        테넌트_ID=테넌트_ID,        vpc_id=vpc_id,        project_type=프로젝트_type,        대상=대상_서브넷_시드르,        next_hop=next_hop,        요청_ID=요청_ID,    )    xaas_service._logger.warning.assert_called_once_with(        f"경로({target_subnet_cidr}, {next_hop})가 이미 존재합니다"    )@pytest.mark.asyncioasync def test_add_route_to_vpc_internal_error(xaas_service):    tenant_id = "tenant-1"    vpc_id = "vpc-1"    project_type = "xaas"    target_subnet_cidr = "10.0.0.0/24"    next_hop = "192.168.0.1"    request_id = "req-1"    xaas_service.network_client.vpcs.add_route_to_vpc.side_effect = Exception()    와 함께```