Add test cases for handling overflows on dequantization and fix size …

…of count7x7 (#78)

* work in progress

* improved tests

* add 16bit and 32bit tests

* add toml

* fix tests

Cargo.toml

@@ -44,6 +44,7 @@ thread-priority = "1.0.0"
 [dev-dependencies]
 rstest = "0.19"
 rand = "0.8"
+rand_chacha = "0.3"
 siphasher = "1"
 
 [[bin]]

src/helpers.rs

@@ -90,6 +90,14 @@ pub fn calc_sign_index(val: i32) -> usize {
     }
 }
 
+#[cfg(test)]
+pub fn get_rand_from_seed(seed: [u8; 32]) -> rand_chacha::ChaCha12Rng {
+    use rand_chacha::rand_core::SeedableRng;
+    use rand_chacha::ChaCha12Rng;
+
+    ChaCha12Rng::from_seed(seed)
+}
+
 /*
 better way to update aritmetic encoding without using special division
 

src/structs/bit_writer.rs

@@ -200,15 +200,13 @@ fn roundtrip_bits() {
 /// verify the the bits roundtrip correctly with random bits
 #[test]
 fn roundtrip_randombits() {
-    use rand::rngs::StdRng;
     use rand::Rng;
-    use rand::SeedableRng;
 
     let mut buf = Vec::new();
 
     const ITERATIONS: usize = 10000;
 
-    let mut rng = StdRng::from_seed([0u8; 32]);
+    let mut rng = crate::helpers::get_rand_from_seed([0u8; 32]);
     let mut test_data = Vec::with_capacity(ITERATIONS);
 
     for _ in 0..ITERATIONS {

src/structs/idct.rs

@@ -344,11 +344,9 @@ pub fn test_idct_with_simple_block() {
 /// implemenation from the original scalar C++ code
 #[test]
 pub fn test_idct_with_random_blocks() {
-    use rand::rngs::StdRng;
     use rand::Rng;
-    use rand::SeedableRng;
 
-    let mut rng = StdRng::from_seed([0u8; 32]);
+    let mut rng = crate::helpers::get_rand_from_seed([0u8; 32]);
     let mut test_data = AlignedBlock::default();
     let mut test_q = [0u16; 64];