master | 0.10.1 |
---|---|
Mocking library for Rust.
Inspired by Google Mock library for C++.
Previous version were implemented as compiler plugin and used
syntex
crate for parsing. Compiler plugins are now deprecated, and
syntex
crate is not maintained anymore.
Version 0.10.0 migrated from compiler plugin implementation
to usage of proc_macro_attribute
feature. Since this feature isn't supported
in stable Rust yet, mockers
is only available on unstable at the moment.
It is possible that support for stable Rust will be implemented even before
proc_macro_attribute
feature stabilization.
In trivial cases migration of your tests to new mockers
version is as
simple as replacing #[derive(Mock)]
with #[derive_mock]
.
For now it is not a full-featured mocking library, but just a prototype to gather feedback. For example, only methods with four or fewer arguments are supported, non-'static lifetimes are not supported and so on.
Mocking magic is implemented using proc_macro_attribute
attribute
which is only available on nightly Rust (it was tested to work with
1.26.0-nightly (3bcda48a3 2018-02-09)). Working on stable Rust
will be supported later.
This is a very short introduction to show what is possible and how it looks. Read User Guide for details.
We will use nightly Rust in this example for simplicity.
For multirust, run the following command:
$ multirust override nightly
Or if you're using rustup:
$ rustup override set nightly
Cargo.toml:
[dev-dependencies]
mockers = "0.10.1"
mockers_derive = "0.10.1"
src/lib.rs:
#![feature(proc_macro)]
#[cfg(test)] extern crate mockers_derive;
#[cfg(test)] use mockers_derive::derive_mock;
#[cfg_attr(test, derive_mock)]
pub trait AirConditioner {
fn make_hotter(&mut self, by: i16);
fn make_cooler(&mut self, by: i16);
fn get_temperature(&self) -> i16;
}
pub fn set_temperature_20(cond: &mut AirConditioner) {
let t = cond.get_temperature();
if t < 20 {
cond.make_hotter(20 + t);
} else {
cond.make_cooler(t - 20);
}
}
#[cfg(test)]
mod test {
use super::*;
use mockers::Scenario;
#[test]
fn test_set_temperature_20() {
let scenario = Scenario::new();
let mut cond = scenario.create_mock_for::<AirConditioner>();
scenario.expect(cond.get_temperature_call().and_return(16));
scenario.expect(cond.make_hotter_call(4).and_return(()));
set_temperature_20(&mut cond);
}
}
Run tests:
$ cargo test
Compiling air v0.1.0 (file:///Users/kriomant/Temp/air)
Running target/debug/air-b2c5f8b6920cb30a
running 1 test
test test::test_set_temperature_20 ... FAILED
failures:
---- test::test_set_temperature_20 stdout ----
thread 'test::test_set_temperature_20' panicked at '
error: unexpected call to `AirConditioner#0.make_hotter(36)`
note: here are active expectations for AirConditioner#0.make_hotter
expectation `AirConditioner#0.make_hotter(4)`:
arg #0: 36 is not equal to 4
'
note: Run with `RUST_BACKTRACE=1` for a backtrace.
failures:
test::test_set_temperature_20
test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured
error: test failed
Copyright © 2016 Mikhail Trishchenkov
Distributed under the MIT License.