Add basic arbitrary-model-tests based fuzzing

Cargo.toml

@@ -29,3 +29,6 @@ travis-ci = { repository = "Lokathor/tinyvec" }
 
 [package.metadata.docs.rs]
 all-features = true
+
+[workspace]
+members = ["fuzz"]

fuzz/.gitignore

@@ -0,0 +1,2 @@
+hfuzz_target/
+hfuzz_workspace/

fuzz/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "tinyvec-fuzz"
+version = "0.1.0"
+authors = []
+edition = "2018"
+publish = false
+
+[dependencies]
+tinyvec = { path = "..", features = ["nightly_slice_partition_dedup"] }
+arbitrary-model-tests = { git = "https://github.com/jakubadamw/arbitrary-model-tests" }
+honggfuzz = "0.5.45"
+arbitrary = "0.2.0"
+better-panic = "0.2.0"
+derive_arbitrary = "0.2.0"

fuzz/README.md

@@ -0,0 +1,11 @@
+## Quickstart
+
+```console
+> cargo install honggfuzz
+> cargo hfuzz run arrayish
+```
+
+When a crash is found:
+```console
+> cargo hfuzz run-debug arrayish hfuzz_workspace/arrayish/*.fuzz
+```

fuzz/src/arb_range.rs

@@ -0,0 +1,61 @@
+use arbitrary::{Arbitrary, Unstructured};
+use std::ops::{Range, RangeBounds, RangeFrom, RangeInclusive, RangeTo, RangeToInclusive, Bound};
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum ArbRange<T> {
+    Range(Range<T>),
+    RangeFrom(RangeFrom<T>),
+    RangeInclusive(RangeInclusive<T>),
+    RangeTo(RangeTo<T>),
+    RangeToInclusive(RangeToInclusive<T>),
+}
+
+impl<T> RangeBounds<T> for ArbRange<T> {
+    fn start_bound(&self) -> Bound<&T> {
+        match self {
+            ArbRange::Range(range) => range.start_bound(),
+            ArbRange::RangeFrom(range) => range.start_bound(),
+            ArbRange::RangeInclusive(range) => range.start_bound(),
+            ArbRange::RangeTo(range) => range.start_bound(),
+            ArbRange::RangeToInclusive(range) => range.start_bound(),
+        }
+    }
+
+    fn end_bound(&self) -> Bound<&T> {
+        match self {
+            ArbRange::Range(range) => range.end_bound(),
+            ArbRange::RangeFrom(range) => range.end_bound(),
+            ArbRange::RangeInclusive(range) => range.end_bound(),
+            ArbRange::RangeTo(range) => range.end_bound(),
+            ArbRange::RangeToInclusive(range) => range.end_bound(),
+        }
+    }
+
+    fn contains<U: ?Sized>(&self, item: &U) -> bool
+    where
+        T: PartialOrd<U>,
+        U: PartialOrd<T>,
+        {
+        match self {
+            ArbRange::Range(range) => range.contains(item),
+            ArbRange::RangeFrom(range) => range.contains(item),
+            ArbRange::RangeInclusive(range) => range.contains(item),
+            ArbRange::RangeTo(range) => range.contains(item),
+            ArbRange::RangeToInclusive(range) => range.contains(item),
+        }
+    }
+}
+
+impl<T: Arbitrary> Arbitrary for ArbRange<T> {
+    fn arbitrary<U: Unstructured + ?Sized>(u: &mut U) -> Result<Self, U::Error> {
+        let variant = u8::arbitrary(u)? % 5;
+        Ok(match variant {
+            0 => ArbRange::Range(T::arbitrary(u)?..T::arbitrary(u)?),
+            1 => ArbRange::RangeFrom(T::arbitrary(u)?..),
+            2 => ArbRange::RangeInclusive(T::arbitrary(u)?..=T::arbitrary(u)?),
+            3 => ArbRange::RangeTo(..T::arbitrary(u)?),
+            4 => ArbRange::RangeToInclusive(..=T::arbitrary(u)?),
+            _ => unreachable!(),
+        })
+    }
+}

fuzz/src/bin/arrayish.rs

@@ -0,0 +1,99 @@
+use derive_arbitrary::Arbitrary;
+use arbitrary_model_tests::arbitrary_stateful_operations;
+use honggfuzz::fuzz;
+use std::{fmt::Debug, iter::FromIterator, ops::{RangeBounds, Bound}};
+
+use tinyvec::ArrayishVec;
+use tinyvec_fuzz::ArbRange;
+
+const CAPACITY: usize = 32;
+
+arbitrary_stateful_operations! {
+    model = Vec<T>,
+    tested = ArrayishVec<[T; CAPACITY]>,
+
+    type_parameters = <
+        T: Default + Clone + Debug + Eq + Ord,
+        R: RangeBounds<usize> + Clone + Debug,
+    >,
+
+    methods {
+        equal {
+            fn as_mut_slice(&mut self) -> &mut [T];
+            fn as_slice(&self) -> &[T];
+            fn clear(&mut self);
+            fn dedup(&mut self);
+            fn insert(&mut self, index: usize, item: T);
+            fn is_empty(&self) -> bool;
+            fn len(&self) -> usize;
+            fn push(&mut self, item: T);
+            fn truncate(&mut self, new_len: usize);
+        }
+
+        equal_with(Vec::from_iter) {
+            fn drain(&self, range: R) -> impl Iterator<Item = T>;
+            fn iter(&self) -> impl Iterator<Item = &T>;
+            fn iter_mut(&self) -> impl Iterator<Item = &mut T>;
+        }
+    }
+
+    pre {
+        match self {
+            Self::insert { index, .. } if index > model.len() => {
+                // TODO: Should test that these identically panic
+                return;
+            }
+            Self::insert { .. } | Self::push { .. } if model.len() == CAPACITY => {
+                return;
+            }
+            Self::drain { ref range } => {
+                // TODO: Should test that these identically panic
+                let start = match range.start_bound() {
+                    Bound::Included(&n) => n,
+                    Bound::Excluded(&n) => n + 1,
+                    Bound::Unbounded => 0,
+                };
+                let end = match range.end_bound() {
+                    // If it's already usize::max, doesn't really matter about adding 1
+                    Bound::Included(&n) => n.checked_add(1).unwrap_or(n),
+                    Bound::Excluded(&n) => n,
+                    Bound::Unbounded => model.len(),
+                };
+                if start > end || end > model.len() {
+                    return;
+                }
+            }
+            _ => {}
+        }
+    }
+}
+
+const MAX_RING_SIZE: usize = 16_384;
+
+fn fuzz_cycle(data: &[u8]) -> Result<(), ()> {
+    use arbitrary::{Arbitrary, FiniteBuffer};
+
+    let mut ring = FiniteBuffer::new(&data, MAX_RING_SIZE).map_err(|_| ())?;
+
+    let mut model = Vec::<u16>::default();
+    let mut tested: ArrayishVec<[u16; 32]> = ArrayishVec::new();
+
+    let mut _op_trace = String::new();
+    while let Ok(op) = <op::Op<u16, ArbRange<usize>> as Arbitrary>::arbitrary(&mut ring) {
+        #[cfg(fuzzing_debug)]
+        _op_trace.push_str(&format!("{}\n", op.to_string()));
+        op.execute_and_compare(&mut model, &mut tested);
+    }
+
+    Ok(())
+}
+
+fn main() -> Result<(), ()> {
+    better_panic::install();
+
+    loop {
+        fuzz!(|data: &[u8]| {
+            let _ = fuzz_cycle(data);
+        });
+    }
+}

fuzz/src/lib.rs

@@ -0,0 +1,3 @@
+mod arb_range;
+
+pub use arb_range::ArbRange;