Tags

Assigning tags

Tests can be associated with an arbitrary number of tags. Each tag is global, and must be a valid Rust identifier. Tags can be assigned to tests using the #[tag] attribute:

#![allow(unused)]
fn main() {
use test_r::{tag, test};

#[tag(tag1)]
#[tag(tag2)]
#[test]
fn tagged_test() {
    assert!(true);
}
}

Tagging entire test suites

It is possible to tag an entire test suite. This can be done by using the #[tag] attribute on the module containing the tests, or alternatively using the tag_suite! macro:

#![allow(unused)]
fn main() {
use test_r::{tag, tag_suite, test};

mod inner1;

tag_suite!(inner1, tag1);

#[tag(tag2)]
mod inner2 {
    // ...
}
}

The tag_suite! macro is necessary because currently it is not possible to put attributes on non-inlined modules.

Running tagged tests

The purpose of tagging tests is to run a subset of the crate’s tests selected by tags. To select tests by tags, use the :tag: prefix when passing the test name to cargo test:

cargo test :tag:tag1

This example will run every test tagged as tag1, but no others.

Selecting untagged tests

Sometimes it is useful to select all tests without a tag. This can be done by using the :tag: prefix with no tag name:

cargo test :tag:

Selecting tests by multiple tags

Multiple tags can be combined with the | (or) and & (and) operators. The & operator has higher precedence than |. So the following example:

cargo test ':tag:tag1|tag2&tag3'

is going to run tests tagged as either tag1 or both tag2 and tag3.

Skipping tests by tag

The :tag: syntax also works with the --skip option. This allows skipping all tests with a specific tag:

cargo test -- --skip ':tag:slow'

This runs all tests except those tagged as slow.