Refactor Encryption logic for improved testing

[mallardduck]

Before the change there are 2 files in util; 0% and 22% respectively.
Before this change, the util package is currently at 50% coverage.

After the change there are 3 files (counting new sub package); 0%, 13% and 70.4% respectively.
After this change, the util package will be at 66.7% coverage.

[alexandreLamarre]

Instead of the filepath + os.ReadFile can use:

backup-restore-operator/e2e/test/test.go

Line 14 in 155b1a9

func Data(filename string) []byte {

this way the tests aren't dependent on specific paths

can also probably move that into a pkg/test instead of e2e/test if you want

[mallardduck]

Maybe as a follow up PR we move that to test, and consider making it more generic? To use:

func Data(testFs embed.FS, filename string) []byte {

So then we can still keep organizing each pkgs test stubs in place?

NVM, I forgot we need to pass the k8s apis we're re-using a file path. So I'm not sure the Data() trick works here, since the apiserver code reads the bytes out the config file itself.

Making a mental note that this area is also something we could potentially workaround in the future with expansions to BROs logic around encryption.

[mallardduck]

/backport release/v6.x

[github-actions]

Not creating port PR, there was an error running git am -3:

Applying: move encryption config specific functions to new package
Applying: refactor to use new package for encryption config
Using index info to reconstruct a base tree...
A	e2e/backup/backup_test.go
A	e2e/backup/setup_test.go
M	pkg/controllers/backup/controller.go
M	pkg/controllers/restore/controller.go
M	pkg/resourcesets/collector.go
M	pkg/util/util.go
Falling back to patching base and 3-way merge...
Auto-merging pkg/util/util.go
CONFLICT (content): Merge conflict in pkg/util/util.go
Auto-merging pkg/resourcesets/collector.go
Auto-merging pkg/controllers/restore/controller.go
Auto-merging pkg/controllers/backup/controller.go
CONFLICT (modify/delete): e2e/backup/setup_test.go deleted in HEAD and modified in refactor to use new package for encryption config. Version refactor to use new package for encryption config of e2e/backup/setup_test.go left in tree.
CONFLICT (modify/delete): e2e/backup/backup_test.go deleted in HEAD and modified in refactor to use new package for encryption config. Version refactor to use new package for encryption config of e2e/backup/backup_test.go left in tree.
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config advice.mergeConflict false"
Patch failed at 0002 refactor to use new package for encryption config

[mallardduck]

Manual backporting it is...

[alexandreLamarre]

I didn't notice this before, but you we should be careful about opening files inside a function and expecting others to close said file.

Can lead to concurrent closes or file descriptor leaks.
We should look into alternative return types instead of os.File. I also don't see this being used by anything other than the tests at the moment.

Will we need this inside the controller logic?