Flag: test args

[steveklabnik]

This issue is part of #125

--test-args:

Using this flag looks like this:

$ rustdoc src/lib.rs --test --test-args ignored

This flag will pass options to the test runner when running documentation tests.
For more, see the chapter on documentation tests.

See also --test.

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Should we keep this flag or not?

[steveklabnik]

This seems quite important.

[hjr3]

I was looking at starting to implement this and I am not sure we need this flag. The existing rustdoc would do something like $ rustdoc x.rs --test --test-args --color=never which made sense because --test was a distinct from --test-args. In this rustdoc, test is a subcommand. It seems better to implement $ rustdoc test --color=never instead of requiring $ rustdoc test --test-args --color=never.

[hjr3]

Current list of test-args: https://github.com/rust-lang/rust/blob/717ac960b51a5a2bbedf0e4da899aec7ab2ab7ee/src/libtest/lib.rs#L353

[hjr3]

Reading through #190, we may not need this flag. Need to find out if we plan to have rustdoc tests be actual tests.