Crowbar OCaml Library

To use the high-performance AFL fuzzing mode, you must have afl-fuzz installed.

1. Create an input directory containing at least one non-empty file.
2. Create an output directory for AFL to store findings.
3. Run the test binary using afl-fuzz with the @@ placeholder to pass inputs to the binary.

afl-fuzz -i test/input -o output ./my_rad_test.exe @@

When AFL discovers an input that causes a property to fail, it will be reported as a crash.

To test your software, define a property using Crowbar.check_eq or Crowbar.check, then register it using Crowbar.add_test. You must specify a name, a list of types to vary (e.g., [int]), and a function that takes those types as arguments to execute the test.

Example of an identity property test:

let identity x =
  Crowbar.check_eq x x

let () =
  Crowbar.(add_test ~name:"identity function" [int] (fun i -> identity i))

Include crowbar in your project's dependencies. Ensure you build a native-code executable, not bytecode.

To enable AFL-based fuzzing, you must build your tests using an OCaml compiler with AFL instrumentation enabled. The easiest way is to use an opam switch with the +afl tag.

$ opam switch 4.06.0+afl
$ eval `opam config env`
$ ./build_my_rad_test.sh

$ opam switch 4.06.0+afl
$ eval `opam config env`
$ ./build_my_rad_test.sh # or your relevant build runes

To run tests in a simple QuickCheck-like mode where Crowbar tests propositions against totally random input, execute your compiled binary with no arguments.

$ ./my_rad_test.exe | head -5