Testing for proxying, including both TOOLS and DUP_TOOLS

[workingjubilee]

(Note: this has been edited by the rustup team)

1.24.0 shipped with the ability to run cargo fmt, untested.

1.24.1 will not have that defect.
We need to test to make sure that:

• rustup correctly proxies to all of its core tools rather than the subset currently checked.
• rustup correctly proxies to its DUP_TOOLS list.

[rbtcollins]

Rustup doesn't do the third Item on your list.

[0xPoe]

Test all proxies on macOS Catalina 10.15.7 19H2 x86_64

All proxies working well.

The package cargo-cache for cargo was also tested.

See: https://discord.com/channels/442252698964721669/463480252723888159/836798461134897152

[0xPoe]

If anyone wants to help test, you can use the following command to upgrade to 1.24.1(linux/macos/git-bash):

$ export RUSTUP_UPDATE_ROOT=https://dev-static.rust-lang.org/rustup
$ rustup self update
info: checking for self-updates
info: downloading self-update
  rustup updated - 1.24.1 (from 1.23.1)

[0xPoe]

@rustbot claim

I will try to test it.

[0xPoe]

Added unit tests to it, maybe we need better integration tests. My intention is to write a script and install and run these proxy tools in the CI, do you have a better way to test them?