feat: add tfsec-checkgen test-check command to test custom check against tf test code

[gabrielleecredera]

• new command tfsec-checktest test-check <custom_check_file> -p <pass.tf> -f <fail.tf>
• number of --pass/-p/--fail/-f flags are optional and variable
• had to modify the internal custom package to expose functions
• subcommand test-check used to prep for future test-checks command that runs tests against more than one custom check files

partially solves #1415

[owenrumney]

Could this be added as an additional command to tfsec-checkgen?

[gabrielleecredera]

I added it as a new command as I think I've seen somewhere that the original purpose of checkgen is to generate custom checks? I'm not sure if that vision is still true tho, let me know if adding it into checkgen is preferred. :)
(unrelated: if the vision is still true, what's the solution expected to look like? some cli q&a to generate a custom check file?)

[owenrumney]

I added it as a new command as I think I've seen somewhere that the original purpose of checkgen is to generate custom checks? I'm not sure if that vision is still true tho, let me know if adding it into checkgen is preferred. :) (unrelated: if the vision is still true, what's the solution expected to look like? some cli q&a to generate a custom check file?)

Yeah, lets stick with it being part of checkgen since its all the same sort of thing.

In answer to the other question, before we moved to defsec we had tfsec-skeleton which asked you a number of questions about services, required labels, required resources. I think it would do similar to that.... I think there is only so far we can go with automating the generation of custom checks so it will be a bit trial and error

[owenrumney]

Thanks again @gabrielleecredera - your contributions are really appreciated ❤️

[owenrumney]

hey @gabrielleecredera - looks like a goimports issue breaking the build

[gabrielleecredera]

hey @gabrielleecredera - looks like a goimports issue breaking the build

apologies, forgot to add the fixed file to the merge commit haha