Doc tests not run with cargo test TESTNAME on stable (1.35.0)

[tspiteri]

The contents of doc/src/lib.rs:

/// ```rust
/// let _ = {};
/// ```
pub fn foo() {}

Running cargo test foo, doc tests matching the pattern are not run for stable 1.35.0, but they run fine with 1.34.2.

$ cargo version
cargo 1.35.0 (6f3e9c367 2019-04-04)
$ cargo test foo
    Finished dev [unoptimized + debuginfo] target(s) in 0.15s
     Running target/debug/deps/doc-86434eb559164ed5

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

$ cargo +1.34.2 test foo
    Finished dev [unoptimized + debuginfo] target(s) in 0.16s
     Running target/debug/deps/doc-f8e8caa996ffb988

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

   Doc-tests doc

running 1 test
test src/lib.rs - foo (line 1) ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

[ehuss]

For now you can use the --doc flag to do doc tests only.

This was changed in #6683. I didn't really consider filters with doc tests. It may not be trivial to fix due to how filters work. We also haven't really concluded how the --doc flag should behave (is it a filter or a mode?).

[tspiteri]

For my actual use case I have almost 900 examples (in the Rug crate). If I write a new example or modify an existing example, the --doc flag is not so helpful.

[ehuss]

I'm not sure I understand. cargo test --doc foo should doctest things that match the name foo, which should be what was asked for in the original report? Can you clarify why that won't work?

[tspiteri]

Oh sorry, I misunderstood. I thought you suggested --doc instead of foo, not as well as foo. Your suggestion works.

[RalfJung]

I was also just very confused by this. The documentation for the <TESTNAME> argument does not mention that this also excludes doctests. Also this means that cargo test filter and cargo test -- filter have different behavior, which is very surprising.