new tests fail on Windows if you have ~/.cargo/config

[ehuss]

If you have a %USERPROFILE%\.cargo\config on Windows with name/email configured, this will be inadvertently picked up in the new test. The test assumes that TempDir is created in a "safe" location, but on Windows this is typically %USERPROFILE%\AppData\Local\Temp. The recursive tree walk will end up picking up the config file.

I don't have any ideas on how to fix this (other than avoiding using ~/.cargo/config). I don't see a way to prevent cargo from walking up the tree, and I don't know of an alternate way to get a temp directory outside of the user's home directory. I'd be happy with just adding a note somewhere (CONTRIBUTING.md?) to alert any potential Windows contributors.

Reproducing

1. Create a file %USERPROFILE%\.cargo\config with these contents:

[cargo-new]
name = "Example"
email = "user@example.com"

2. Run cargo test --test new

Current Behavior

The following tests fail:

test finds_author_priority ... FAILED
test finds_author_email ... FAILED
test finds_author_user ... FAILED
test finds_git_author ... FAILED
test finds_author_username ... FAILED
test finds_author_user_escaped ... FAILED
test finds_git_email ... FAILED