How to execute cargo test using the nightly channel?

The command line solution may help you to configure your IDE:

cargo +nightly test

Provided, of course, that you have the nightly channel installed. If not, perhaps install it with rustup install nightly (no need to switch to it, but check you're still on stable: rustup show).

The +<toolchain> functionality comes from rustup, the Rust toolchain manager. It works for both cargo +<toolchain> as well as rustc +<toolchain>.

In addition, you can use

• rustup run <toolchain> <any arbitrary command goes here>
• Since your project requires nightly features, you can change into the directory and run rustup override set <toolchain> to always use the nightly toolchain in that directory.
• Create a file called rust-toolchain in your directory containing the name of the toolchain required (e.g. nightly). This has the safe effect as an override, but can be committed to source control.

See also:

• Is it possible to have multiple coexisting Rust installations?