update: Skips deleted and in deletion NAT gateways from nuking, adds test for config file lookup

[GiamPy5]

Description

Solves #310.

Edit: I initially thought it would solve issue number 310, but the real problem is in the README.md since it's misleading and doesn't match with the Config key in the Go code (https://github.com/gruntwork-io/cloud-nuke/blob/master/config/config.go#L16). So this PR actually just adds a test and verifies that the code works properly (which it does), and adds a small verification step in the lookup function to make sure that it doesn't retrieve NAT gateways that are deleted or in deletion.

TODOs

Read the Gruntwork contribution guidelines.

• Update the docs.
• Run the relevant tests successfully, including pre-commit checks.
• Ensure any 3rd party code adheres with our license policy or delete this line if its not applicable.
• Include release notes. If this PR is backward incompatible, include a migration guide.

Release Notes (draft)

• Added test to verify that looking up NAT Gateways with the configuration file works.
• Updated the NAT Gateway lookup method so that it does not retrieve deleted or in deletion resources.

Migration Guide

None.

[denis256]

Hi,
I'm not sure if this PR will change behavior of cloud-nuke, since it has changes only in *_test.go which is not included in the final build and it will not influence on NAT gateway filtering

[GiamPy5]

Hi,

I'm not sure if this PR will change behavior of cloud-nuke, since it has changes only in *_test.go which is not included in the final build and it will not influence on NAT gateway filtering

I agree, this was just the test to confirm the bug. I wasn't able to fix it yet because I didn't have any default VPC to work with, but I was able to recreate it so I'll have the fix ready soon!

[GiamPy5]

OK so it looks like that maybe it was a problem on our side, the config file contained NATGateway instead of NatGateway, maybe it could be interesting verifying in the future if the config file contains invalid keys so that we avoid these false alarms?

Regardless, I think this PR still adds a bit of value since now I've added the test with the configuration file, and the lookup function is also more precise is not getting deleting/deleted NAT gateways.

[yorinasub17]

LGTM