doctest! seems to not work any more?

[BurntSushi]

Consider the following:

$ tree -I target
.
├── Cargo.lock
├── Cargo.toml
├── README.md
└── src
    └── lib.rs

1 directory, 4 files

$ cat Cargo.toml
[package]
name = "doc-comment-fail"
version = "0.1.0"
authors = ["Andrew Gallant <jamslam@gmail.com>"]
edition = "2018"

[dependencies]
doc-comment = "0.3.1"

$ cat src/lib.rs
#[cfg(test)]
doc_comment::doctest!("../README.md");

pub fn something() {}

$ cat README.md
```rust
fn main() {
  this is an invalid program
}

Since my Rust program in my README is invalid, I expected cargo test to fail. But instead, it passes and does not seem to run any tests:

$ cargo test
    Finished test [unoptimized + debuginfo] target(s) in 0.01s
     Running target/debug/deps/doc_comment_fail-fe51e9186885559c

running 0 tests

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

   Doc-tests doc-comment-fail

running 0 tests

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

Did something break this functionality or am I perhaps just doing something wrong?

If I run cargo expand, then it shows the macro is still expanding seemingly correctly:

$ cargo expand --color never --lib --tests
   Compiling doc-comment-fail v0.1.0 (/tmp/doc-comment-fail)
    Finished test [unoptimized + debuginfo] target(s) in 0.04s

#![feature(prelude_import)]
#[prelude_import]
use std::prelude::v1::*;
#[macro_use]
extern crate std;
///```rust
///fn main() {
///  this is an invalid program
///}
///```
extern "C" {}
pub fn something() {}
#[main]
pub fn main() -> () {
    extern crate test;
    test::test_main_static(&[])
}

If I inline the relevant bits of cargo expand into src/lib.rs manually, then the test fails, as I expect:

$ cat src/lib.rs
///```rust
///fn main() {
///  this is an invalid program
///}
///```
extern "C" {}

pub fn something() {}

$ cargo test
   Compiling doc-comment-fail v0.1.0 (/tmp/doc-comment-fail)
    Finished test [unoptimized + debuginfo] target(s) in 0.19s
     Running target/debug/deps/doc_comment_fail-fe51e9186885559c

running 0 tests

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

   Doc-tests doc-comment-fail

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

failures:

---- src/lib.rs -  (line 1) stdout ----
error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `is`
 --> src/lib.rs:3:8
  |
3 |   this is an invalid program
  |        ^^ expected one of 8 possible tokens

error: aborting due to previous error

Couldn't compile the test.

failures:
    src/lib.rs -  (line 1)

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

error: test failed, to rerun pass '--doc'

[GuillaumeGomez]

It's not cfg(test) that you want but cfg(doctest). ;)

[BurntSushi]

Ah right, completely forgot about that. Might be good to re-purpose this ticket into adding a quick note about that in the docs. Or even just use cfg(doctest) in the crate examples.

[GuillaumeGomez]

Oh good idea! I'll send a fix shortly.