How do you test/develop your AWS Lambdas locally?

Hi, im currently implementing AWS SAM to test and develop my lambdas locally, which works wonder in every scenario BUT the one i have. My lambdas get the information i need to use from RDS instance, which is on a VPC and it seems that when running the invoke lambda, just when it tries to make the connection it times out. I Tried using AWS Toolkit as well, where i create the SAM template given the lambda i have on my AWS resources, configuring automatically the SubnetsIds on the VPC Config and everything, but it doesnt seem to work. The option i have is to work it with dummy data, but i dont know if that is the common option so i wanted to ask you the title's question. And if you could, help me to find the proper way to work this out. Thanks in advance!