checkers

Checkers is a simple allocation checker for Rust. It plugs in through the [global allocator] API and can sanity check your unsafe Rust during integration testing.

It can check for the following things: * Double-frees. * Attempts to free regions which are not allocated. * Attempts to free only part of regions which are allocated. * Attempts to free a region with a [mismatching layout]. * Underlying allocator producting regions not adhering to the requested layout. Namely size and alignment. * Other arbitrary user-defined conditions ([see test]).

What it can't do: * Test multithreaded code. Since the allocator is global, it is difficult to scope the state for each test case.

Examples

You use checkers by installing checkers::Allocator as your allocator, then making use of either the #[checkers::test] macro or the checkers::with function.

```rust

[global_allocator]

static ALLOCATOR: checkers::Allocator = checkers::Allocator;

[checkers::test]

fn testallocations() { let _ = Box::intoraw(Box::new(42)); } ```

The above would result in the following test output:

text dangling region: 0x226e5784f30-0x226e5784f40 (size: 16, align: 8). thread 'test_leak_box' panicked at 'allocation checks failed', tests\leaky_tests.rs:4:1

With checkers::with, we can perform more detailed diagnostics:

```rust

[global_allocator]

static ALLOCATOR: checkers::Allocator = checkers::Allocator;

let snapshot = checkers::with(|| { let _ = vec![1, 2, 3, 4]; });

asserteq!(2, snapshot.events.len()); assert!(snapshot.events[0].isallocationwith(|r| r.size >= 16)); assert!(snapshot.events[1].isdeallocationwith(|a| a.size >= 16)); asserteq!(1, snapshot.events.allocations()); asserteq!(1, snapshot.events.deallocations()); assert!(snapshot.events.maxmemory_used().unwrap() >= 16); ```