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//! Property-based tests for SafeDeserializer.
//!
//! These tests verify the correctness properties defined in the design document:
//! - Property 1: Deserialization Safety Invariant
//! - Property 6: Safe Deserializer Round-Trip
#[cfg(test)]
mod property_tests {
// use crate::machine::safe_deserialize::SafeDeserializer;
use crate::safety::SafetyError;
use proptest::prelude::*;
use std::mem::size_of;
// ========================================================================
// Property 1: Deserialization Safety Invariant
// Feature: codebase-safety-audit, Property 1: Deserialization Safety Invariant
// Validates: Requirements 1.1, 1.2, 1.3, 1.5
// ========================================================================
proptest! {
#![proptest_config(ProptestConfig::with_cases(1000))]
/// Property 1: For any type T and byte slice, deserialization succeeds iff:
/// - slice.len() >= size_of::<T>() AND
/// - slice.as_ptr() is aligned to align_of::<T>()
#[test]
fn prop_deserialize_validates_size_u32(
buffer_len in 0usize..100,
) {
let buffer = vec![0u8; buffer_len];
let mut deserializer = SafeDeserializer::new(&buffer);
let result: Result<&u32, _> = deserializer.read();
if buffer_len >= size_of::<u32>() {
// Buffer is large enough, should succeed (alignment is guaranteed for Vec)
prop_assert!(result.is_ok(), "Expected Ok for buffer_len={}", buffer_len);
} else {
// Buffer too small, should fail
prop_assert!(
matches!(result, Err(SafetyError::BufferTooSmall { .. })),
"Expected BufferTooSmall for buffer_len={}, got {:?}",
buffer_len, result
);
}
}
/// Property 1: Test with u64 type (8-byte alignment)
#[test]
fn prop_deserialize_validates_size_u64(
buffer_len in 0usize..100,
) {
let buffer = vec![0u8; buffer_len];
let mut deserializer = SafeDeserializer::new(&buffer);
let result: Result<&u64, _> = deserializer.read();
if buffer_len >= size_of::<u64>() {
prop_assert!(result.is_ok(), "Expected Ok for buffer_len={}", buffer_len);
} else {
prop_assert!(
matches!(result, Err(SafetyError::BufferTooSmall { .. })),
"Expected BufferTooSmall for buffer_len={}, got {:?}",
buffer_len, result
);
}
}
/// Property 1: Test sequential reads consume buffer correctly
#[test]
fn prop_sequential_reads_track_position(
num_values in 1usize..10,
) {
let buffer_size = num_values * size_of::<u32>();
let buffer = vec![0u8; buffer_size];
let mut deserializer = SafeDeserializer::new(&buffer);
for i in 0..num_values {
let result: Result<&u32, _> = deserializer.read();
prop_assert!(result.is_ok(), "Read {} should succeed", i);
prop_assert_eq!(
deserializer.position(),
(i + 1) * size_of::<u32>(),
"Position after read {}", i
);
}
// Next read should fail (buffer exhausted)
let result: Result<&u32, _> = deserializer.read();
prop_assert!(result.is_err(), "Read past end should fail");
}
/// Property 1: Test read_slice validates count * size
#[test]
fn prop_read_slice_validates_total_size(
buffer_len in 0usize..100,
count in 0usize..20,
) {
// Use an aligned buffer to avoid alignment issues
// Vec<u32> guarantees proper alignment for u32
let aligned_buffer: Vec<u32> = vec![0u32; buffer_len.div_ceil(4)];
// SAFETY: Creating a byte view of the aligned buffer.
// aligned_buffer is a valid Vec<u32>, so its pointer and length are valid.
// We're creating a byte slice view that doesn't exceed the buffer bounds.
let buffer = unsafe {
std::slice::from_raw_parts(
aligned_buffer.as_ptr() as *const u8,
buffer_len.min(aligned_buffer.len() * 4)
)
};
let actual_buffer_len = buffer.len();
let mut deserializer = SafeDeserializer::new(buffer);
let result: Result<&[u32], _> = deserializer.read_slice(count);
let needed = count * size_of::<u32>();
if actual_buffer_len >= needed {
prop_assert!(result.is_ok(), "Expected Ok for buffer_len={}, count={}", actual_buffer_len, count);
prop_assert_eq!(result.unwrap().len(), count);
} else {
prop_assert!(result.is_err(), "Expected error for buffer_len={}, count={}", actual_buffer_len, count);
}
}
/// Property 1: Test that misaligned buffers are rejected
#[test]
fn prop_misaligned_buffer_rejected(
base_len in 16usize..100,
misalign in 1usize..8,
) {
// Create an aligned buffer
let aligned: Vec<u64> = vec![0; (base_len / 8) + 2];
let base_ptr = aligned.as_ptr() as *const u8;
// SAFETY: We're creating a test slice to verify misalignment detection.
// base_ptr points to a valid Vec<u64>, and we're creating a slice within its bounds.
// The misalignment is intentional to test the safety checks.
// Create a misaligned slice
let slice = unsafe {
let ptr = base_ptr.add(misalign);
let len = base_len.saturating_sub(misalign);
std::slice::from_raw_parts(ptr, len.min(aligned.len() * 8 - misalign))
};
let mut deserializer = SafeDeserializer::new(slice);
let result: Result<&u64, _> = deserializer.read();
// Should fail due to misalignment (u64 requires 8-byte alignment)
if slice.len() >= 8 {
prop_assert!(
matches!(result, Err(SafetyError::Misaligned { .. })),
"Expected Misaligned for misalign={}, got {:?}",
misalign, result
);
}
}
}
// ========================================================================
// Property 6: Safe Deserializer Round-Trip
// Feature: codebase-safety-audit, Property 6: Safe Deserializer Round-Trip
// Validates: Requirements 1.1, 1.2
// ========================================================================
proptest! {
#![proptest_config(ProptestConfig::with_cases(500))]
/// Property 6: Round-trip for u32 values
#[test]
fn prop_roundtrip_u32(value: u32) {
let bytes = value.to_le_bytes();
let mut deserializer = SafeDeserializer::new(&bytes);
let read_value: &u32 = deserializer.read().unwrap();
prop_assert_eq!(*read_value, value);
}
/// Property 6: Round-trip for u64 values
#[test]
fn prop_roundtrip_u64(value: u64) {
let bytes = value.to_le_bytes();
let mut deserializer = SafeDeserializer::new(&bytes);
let read_value: &u64 = deserializer.read().unwrap();
prop_assert_eq!(*read_value, value);
}
/// Property 6: Round-trip for i64 values
#[test]
fn prop_roundtrip_i64(value: i64) {
let bytes = value.to_le_bytes();
let mut deserializer = SafeDeserializer::new(&bytes);
let read_value: &i64 = deserializer.read().unwrap();
prop_assert_eq!(*read_value, value);
}
/// Property 6: Round-trip for f64 values
#[test]
fn prop_roundtrip_f64(value: f64) {
let bytes = value.to_le_bytes();
let mut deserializer = SafeDeserializer::new(&bytes);
let read_value: &f64 = deserializer.read().unwrap();
// Use to_bits for comparison to handle NaN correctly
prop_assert_eq!(read_value.to_bits(), value.to_bits());
}
/// Property 6: Round-trip for slice of u32 values
#[test]
fn prop_roundtrip_slice_u32(values in prop::collection::vec(any::<u32>(), 0..20)) {
// Create a properly aligned buffer
let buffer: Vec<u32> = values.clone();
// SAFETY: Creating a byte view of a valid u32 slice.
// buffer is a valid Vec<u32>, so its pointer and length are valid.
// We're creating a byte slice view of exactly buffer.len() * 4 bytes.
let bytes = unsafe {
std::slice::from_raw_parts(
buffer.as_ptr() as *const u8,
buffer.len() * size_of::<u32>()
)
};
let mut deserializer = SafeDeserializer::new(bytes);
let read_values: &[u32] = deserializer.read_slice(values.len()).unwrap();
prop_assert_eq!(read_values, values.as_slice());
}
}
// ========================================================================
// Additional Safety Tests
// ========================================================================
proptest! {
#![proptest_config(ProptestConfig::with_cases(200))]
/// Test that skip validates bounds
#[test]
fn prop_skip_validates_bounds(
buffer_len in 0usize..100,
skip_len in 0usize..150,
) {
let buffer = vec![0u8; buffer_len];
let mut deserializer = SafeDeserializer::new(&buffer);
let result = deserializer.skip(skip_len);
if skip_len <= buffer_len {
prop_assert!(result.is_ok());
prop_assert_eq!(deserializer.position(), skip_len);
} else {
prop_assert!(result.is_err());
}
}
/// Test that seek validates bounds
#[test]
fn prop_seek_validates_bounds(
buffer_len in 0usize..100,
seek_pos in 0usize..150,
) {
let buffer = vec![0u8; buffer_len];
let mut deserializer = SafeDeserializer::new(&buffer);
let result = deserializer.seek(seek_pos);
if seek_pos <= buffer_len {
prop_assert!(result.is_ok());
prop_assert_eq!(deserializer.position(), seek_pos);
} else {
prop_assert!(result.is_err());
}
}
/// Test remaining() is always accurate
#[test]
fn prop_remaining_accurate(
buffer_len in 0usize..100,
reads in 0usize..10,
) {
let buffer = vec![0u8; buffer_len];
let mut deserializer = SafeDeserializer::new(&buffer);
prop_assert_eq!(deserializer.remaining(), buffer_len);
let actual_reads = reads.min(buffer_len);
for _ in 0..actual_reads {
let _ = deserializer.read_bytes(1);
}
prop_assert_eq!(
deserializer.remaining(),
buffer_len.saturating_sub(actual_reads)
);
}
}
}