Module fuzzcheck::builder

Expand description

Builders used to set up a fuzz test.

This module contains 5 types to build a fuzz test: FuzzerBuilder[1–5].

The idea is to help you specify each part of the fuzzer progressively:

the function to fuzz
the mutator to generate arguments to the test function (called “inputs” or “test cases”)
the serializer to save test cases to the file system
the sensor to provide feedback after running the test function, and the pool to interpret the feedback from the sensor
other settings for the fuzzer, such as the maximum allowed complexity for the test cases, where to save the corpora or artifacts on the file system, etc.

In most cases, you don’t need to manually specify all these components. If the argument type of the function has a default mutator and is serializable with serde, then you can write:

let _ = fuzzcheck::fuzz_test(test_function) // FuzzerBuilder1
    .default_options() // FuzzerBuilder5!  we use the default values for stages 2 to 5
    .launch();

This is equivalent to:

let _ = fuzzcheck::fuzz_test(test_function)
    .default_mutator()      // the default is `<T as DefaultMutator>::default_mutator()`
    .serde_serializer()   // the default is `SerdeSerializer::new()`
    .default_sensor_and_pool() // the default is `default_sensor_and_pool().finish()`
    .arguments_from_cargo_fuzzcheck()
    .launch();

If you’d like to use a custom mutator, serializer, sensor and pool, or arguments, you can write:

let _ = fuzzcheck::fuzz_test(test_function)
    .mutator(my_mutator)         // the default is `<T as DefaultMutator>::default_mutator()`
    .serializer(my_serializer)   // the default is `SerdeSerializer::new()`
    .sensor_and_pool(sensor, pool)
    .arguments(arguments)
    .launch();

To build a custom sensor and pool, you may want to look at the Sensor, Pool, and CompatibleWithObservations traits. You can also look at the types provided in the sensors_and_pools module. But the easiest way to customize them is to use the SensorAndPoolBuilder, although it only offers a couple limited options.