String support

[fernandobatels]

Hi, maybe is a my mistake, but i cant use the String type with 'stdout', only the str type.

    let mut main = Command::main_binary().unwrap();

    main.arg("tags")
        .arg("list")
        .arg("--use-csv");

    let stdout = String::from("\"Name\",\"#id\"");

    // stdout.push_str ....
    // stdout.push_str ....
    // stdout.push_str ....
  
    main.assert()
        .success()
        .stdout(stdout.as_str());

On run this, i receive error[E0597]: stdout does not live long enough. I cant use .stdout(stdout.as_str());, because i receive the trait assert_cmd::assert::IntoOutputPredicate<_> is not implemented for std::string::String.

Where am I going wrong :( ?

Thank you in advance for your attention.

[epage]

Overlooked this, sorry. Preparing a fix.

On a related note, I'm not sure why I made the predicate store a Cow<'static, str> rather than allowing more flexible borrows. I'm holding off on addressing that because it'll take more investigation.

[epage]

Oh and this could have been worked around by constructing the predicates but that is also a bit more work :)

[fernandobatels]

Thank you very much, the new version(v0.10.2) fix the problem. :)