2 releases
0.1.1 | Dec 21, 2022 |
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0.1.0 | Dec 21, 2022 |
#612 in Testing
18KB
154 lines
crossroads
library
This library consists of a single proc macro with a simple purpose: Turn one function into potentially many!
To motivate this, assume you have a couple of test cases like these:
use std::collections::HashMap;
#[test]
fn empty_be_default() {
let map: HashMap<String, usize> = Default::default();
assert!(map.is_empty());
}
#[test]
fn empty_after_clear() {
let mut map: HashMap<String, usize> = Default::default();
map.insert("test".to_string(), 1);
map.clear();
assert!(map.is_empty());
}
#[test]
fn empty_after_remove() {
let mut map: HashMap<String, usize> = Default::default();
map.insert("test".to_string(), 1);
map.remove("test");
assert!(map.is_empty());
}
This crate allows you to write the following instead:
use std::collections::HashMap;
use crossroads::crossroads;
#[crossroads]
#[test]
fn empty() {
let mut map: HashMap<String, usize> = Default::default();
match fork!() {
by_default => {}
after_add => {
map.insert("Key".to_owned(), 1337);
match fork!() {
and_remove => map.remove("Key"),
and_clear => map.clear(),
};
}
}
assert!(map.is_empty());
}
The macro computes every possible path through the fork!()
s and creates a version of the function for it.
These can then be picked up by the test system (as attributes below the #[crossroads]
attribute are cloned as
well). In this case, you will get output like this (run cargo test --examples
to reproduce:
running 3 tests
test empty_by_default ... ok
test empty_after_add_and_clear ... ok
test empty_after_add_and_remove ... ok
The idea is inspired
by @Nested
tests in JUnit 5
, sections in Catch2
and subtests in doctest
.
Questions
Answers to common questions:
- Why did you decide to use the standard
match
syntax instead of introducing a custom one, for examplefork! { a => { .. }, b => { .. }}
?
It would indeed be possible to offer a completely custom syntax with the proc macro. However, I decided to just latch
onto the match
structure as it makes code-formatting tools, in particular rustfmt
work a lot more smoothly.
Contributions
I welcome any suggestions/feature requests/changes/bug fixes. Feel free to open a PR if you already have concrete changes at hand. Alternatively, open an issue and we can discuss possible solutions/viability.
Please note that any contributions that you make to this project are assumed to be licensed under the same license(s) as the remainder of project. Make sure that you are legally allowed to grant such licenses to your work.
General requirements:
- CI checks must all pass on your PR.
- After review/approval, please rebase to the latest version of the
master
branch.
License
The library is licensed under MIT license, see LICENSE
for details.
Dependencies
~1.5MB
~34K SLoC