cleanup: Do not use path calculation in multi-index integration tests

[ahmetb]

Right now the integration tests for TestKrewIndex** methods have:

localIndex := test.TempDir().Path("index/" + constants.DefaultIndexName)

We should avoid guessing directory layouts in the test code, and in general.

environment.Paths type is supposed to calculate path segments.

It's advisable to move these to use:

localIndex := environment.NewPaths(test.Root()).IndexPath(constants.DefaultIndexName)

after the multi-index switch can be removed. Otherwise these tests will also need os.Setenv + "defer os.Unsetenv" with constants.EnableMultiIndexSwitch to influence how environment.Paths computes paths.

cc: @chriskim06
/kind cleanup
/priority important-soon
/area multi-index

[chriskim06]

Should we switch these to use environment.Paths/Setenv and Unsetenv now? There's the item in #566 to remove the multi-index flag feature where the Setenv and Unsetenv could be cleaned up in the tests along with the os.Getenv(...) calls in the code.

[ahmetb]

Since it's tied to that this is probably one of the last items to do. But take it for a spin if you're sure we can churn through the list rather quickly.

[ahmetb]

@chriskim06 any ideas if this is addressed?

[chriskim06]

I haven''t started this yet, but should be able to get to it fairly soon.