Crates.io | simple_test_case |
lib.rs | simple_test_case |
version | 1.2.0 |
source | src |
created_at | 2022-01-29 15:57:58.823082 |
updated_at | 2023-07-20 08:05:51.964502 |
description | A bare bones attribute macro for writing parameterised tests |
homepage | |
repository | https://github.com/sminez/simple_test_case |
max_upload_size | |
id | 523680 |
size | 33,684 |
You don't want to have to worry about bugs in your test suite or unexpected behaviour leading
to failing tests silently passing. With that in mind, simple_test_case
aims to do the bare
minimum to eliminate the boilerplate of writing parameterised tests and no more.
The test_case
attribute macro handles generating multiple test functions for you which are
parameterised by the inputs you provide. You still need to provide the #[test]
attribute (or
an alternative such as #[tokio::test]
) and all test cases must be provided before any
additional attribute macros you wish to apply.
And that's it.
There is no additional support for custom assertions, fixtures etc. That said, if you want or
need a more complicated testing set up, additional attribute macros should play nice with
simple_test_case
provided you follow the advice below.
Here the #[test]
attribute is provided after all instances of test_case
. This will work.
use simple_test_case::test_case;
fn double(n: usize) -> usize {
n * 2
}
#[test_case(1, 2; "case 1")]
#[test_case(3, 6; "case 2")]
#[test]
fn double_test(n: usize, double: usize) {
assert_eq!(double(n), double)
}
Here the #[test]
attribute is provided before all instances of test_case
. This will cause
the compiler to complain about functions used as tests not being allowed to have any arguments.
use simple_test_case::test_case;
fn double(n: usize) -> usize {
n * 2
}
#[test]
#[test_case(1, 2; "case 1")]
#[test_case(3, 6; "case 2")]
fn double_test(n: usize, double: usize) {
assert_eq!(double(n), double)
}
test_case
preserves all attributes beneath it, forwarding them on to the individual generated
test functions. As an example, the standard library should_panic
attribute works just fine as
shown below (just make sure to provide your test cases first as described above):
use simple_test_case::test_case;
#[test_case(1, 2; "case 1")]
#[test_case(3, 6; "case 2")]
#[test]
#[should_panic(expected = "this works")]
fn panic_test(n: usize, double: usize) {
assert_eq!(double(a), b);
panic!("this works")
}
Async tests are supported in the same way that all other attributes are supported: add your tests cases first and then apply the async testing macro of your choice beneath.
use simple_test_case::test_case;
async fn async_double(n: usize) -> usize {
n * 2
}
#[test_case(1, 2; "case 1")]
#[test_case(3, 6; "case 2")]
#[tokio::test]
async fn double_test(n: usize, double: usize) {
assert_eq!(double(n).await, double)
}
You are encouraged to read the source of the macro itself (the macro plus associated helper functions are under 150 lines of code) but the general idea is as follows:
test_case
(or simple_test_case::test_case
) attributes, each of which maps a
set of function arguments to a test case name.You can use cargo expand to see what the generated
tests look like using the example provided in the examples
directory like so:
$ cargo expand --example=expand_me --tests
Compiling simple_test_case v0.1.0 (/home/innes/repos/personal/simple_test_case)
Finished test [unoptimized + debuginfo] target(s) in 0.12s
#![feature(prelude_import)]
#[prelude_import]
use std::prelude::rust_2021::*;
#[macro_use]
extern crate std;
use simple_test_case::test_case;
mod example {
#[allow(unused_imports)]
use super::*;
extern crate test;
#[cfg(test)]
#[rustc_test_marker]
pub const small_example: test::TestDescAndFn = test::TestDescAndFn {
desc: test::TestDesc {
name: test::StaticTestName("example::small_example"),
ignore: false,
allow_fail: false,
compile_fail: false,
no_run: false,
should_panic: test::ShouldPanic::No,
test_type: test::TestType::Unknown,
},
testfn: test::StaticTestFn(|| test::assert_test_result(small_example())),
};
fn small_example() {
let a: usize = 1;
let b: usize = 2;
if !(a < b) {
::core::panicking::panic("assertion failed: a < b")
}
}
extern crate test;
#[cfg(test)]
#[rustc_test_marker]
pub const large_example: test::TestDescAndFn = test::TestDescAndFn {
desc: test::TestDesc {
name: test::StaticTestName("example::large_example"),
ignore: false,
allow_fail: false,
compile_fail: false,
no_run: false,
should_panic: test::ShouldPanic::No,
test_type: test::TestType::Unknown,
},
testfn: test::StaticTestFn(|| test::assert_test_result(large_example())),
};
fn large_example() {
let a: usize = 100;
let b: usize = 200;
if !(a < b) {
::core::panicking::panic("assertion failed: a < b")
}
}
}
#[allow(dead_code)]
fn main() {}
#[rustc_main]
pub fn main() -> () {
extern crate test;
test::test_main_static(&[&small_example, &large_example])
}