Fix felt serialization in snforge-test-collector (#1318)

Closes #1317

Fixes felt serialization in `snforge-test-collector` by using wrapper
with custom `serde::Serialize` implementation that is mimicking old
`Felt252` implementation (wrapper over `BigUint`)

extensions/scarb-snforge-test-collector/src/compilation/test_collector/config.rs

@@ -1,3 +1,4 @@
+use crate::felt252::Felt252;
 use anyhow::Result;
 use cairo_lang_defs::plugin::PluginDiagnostic;
 use cairo_lang_diagnostics::Severity;
@@ -12,7 +13,6 @@ use cairo_lang_utils::OptionHelper;
 use num_bigint::BigInt;
 use num_traits::ToPrimitive;
 use serde::Serialize;
-use starknet_types_core::felt::Felt as Felt252;
 use std::num::NonZeroU32;
 
 const FORK_ATTR: &str = "fork";
@@ -31,7 +31,9 @@ impl From<PanicExpectation> for ExpectedPanicValue {
     fn from(value: PanicExpectation) -> Self {
         match value {
             PanicExpectation::Any => ExpectedPanicValue::Any,
-            PanicExpectation::Exact(vec) => ExpectedPanicValue::Exact(vec),
+            PanicExpectation::Exact(vec) => {
+                ExpectedPanicValue::Exact(vec.into_iter().map(Felt252::new).collect())
+            }
         }
     }
 }

extensions/scarb-snforge-test-collector/src/felt252.rs

@@ -0,0 +1,81 @@
+use serde::{
+    ser::{SerializeMap, SerializeSeq},
+    Serialize, Serializer,
+};
+use std::collections::HashMap;
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Felt252(WrapperInner);
+
+impl Felt252 {
+    pub fn new(felt: starknet_types_core::felt::Felt) -> Self {
+        Self(WrapperInner(felt))
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+struct WrapperInner(starknet_types_core::felt::Felt);
+
+impl Serialize for Felt252 {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let sub_map: HashMap<_, _> = [("val", self.0.clone())].into_iter().collect();
+
+        let mut map = serializer.serialize_map(Some(1))?;
+        map.serialize_entry("value", &sub_map)?;
+        map.end()
+    }
+}
+
+// this is copy-pasted BigUint (old felt implementation) inner serialization with inlining
+impl Serialize for WrapperInner {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut data: Vec<_> = self
+            .0
+            .to_bytes_le()
+            .chunks(8)
+            .map(|chunk| {
+                chunk
+                    .iter()
+                    .rev()
+                    .fold(0, |acc, &c| (acc << 8) | u64::from(c))
+            })
+            .collect();
+
+        normalize(&mut data);
+
+        if let Some((&last, data)) = data.split_last() {
+            let last_lo = last as u32;
+            let last_hi = (last >> 32) as u32;
+            let u32_len = data.len() * 2 + 1 + (last_hi != 0) as usize;
+            let mut seq = serializer.serialize_seq(Some(u32_len))?;
+            for &x in data {
+                seq.serialize_element(&(x as u32))?;
+                seq.serialize_element(&((x >> 32) as u32))?;
+            }
+            seq.serialize_element(&last_lo)?;
+            if last_hi != 0 {
+                seq.serialize_element(&last_hi)?;
+            }
+            seq.end()
+        } else {
+            let data: &[u32] = &[];
+            data.serialize(serializer)
+        }
+    }
+}
+
+fn normalize(data: &mut Vec<u64>) {
+    if let Some(&0) = data.last() {
+        let len = data.iter().rposition(|&d| d != 0).map_or(0, |i| i + 1);
+        data.truncate(len);
+    }
+    if data.len() < data.capacity() / 4 {
+        data.shrink_to_fit();
+    }
+}

extensions/scarb-snforge-test-collector/src/main.rs

@@ -13,6 +13,7 @@ use crate::metadata::compilation_unit_for_package;
 
 mod compilation;
 mod crate_collection;
+mod felt252;
 mod metadata;
 
 /// Starknet Foundry private extension for compiling test artifacts.

extensions/scarb-snforge-test-collector/tests/test.rs

@@ -285,7 +285,6 @@ const SHOULD_PANIC_TEST: &str = indoc! {r#"
 };
 
 #[test]
-#[ignore = "TODO: fix felt serialization"]
 fn forge_test_with_should_panic_message_attribute() {
     let t = TempDir::new().unwrap();
     let pkg1 = t.child("forge");