Refactor event logic (foundry-rs#2251)

<!-- Reference any GitHub issues resolved by this PR -->

Closes foundry-rs#1889 

## Introduced changes

<!-- A brief description of the changes -->

- revamp event logic

Original stack here:
- foundry-rs#2193 
- foundry-rs#2194 
- foundry-rs#2195
- foundry-rs#2224 

## Checklist

<!-- Make sure all of these are complete -->

- [ ] Linked relevant issue
- [ ] Updated relevant documentation
- [ ] Added relevant tests
- [ ] Performed self-review of the code
- [ ] Added changes to `CHANGELOG.md`

CHANGELOG.md

@@ -14,6 +14,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 #### Changed
 
 - `SyscallResultStringErrorTrait::map_error_to_string` removed in favor of utility function (`snforge_std::byte_array::try_deserialize_bytearray_error`)
+- Updated event testing - read more [here](./docs/src/testing/testing-events.md) on how it now works and [here](./docs/src/appendix/cheatcodes/spy_events.md)
+about updated `spy_events` cheatcode
 
 ### Cast
 

crates/cheatnet/src/runtime_extensions/call_to_blockifier_runtime_extension/execution/syscall_hooks.rs

@@ -37,14 +37,7 @@ pub fn emit_event_hook(
 ) {
     let contract_address = syscall_handler.contract_address();
     let last_event = syscall_handler.last_event();
-    let is_spied_on = cheatnet_state
-        .spies
-        .iter()
-        .any(|spy_on| spy_on.does_spy(contract_address));
-
-    if is_spied_on {
-        cheatnet_state
-            .detected_events
-            .push(Event::from_ordered_event(last_event, contract_address));
-    }
+    cheatnet_state
+        .detected_events
+        .push(Event::from_ordered_event(last_event, contract_address));
 }

crates/cheatnet/src/runtime_extensions/forge_runtime_extension/cheatcodes/spy_events.rs

@@ -1,13 +1,11 @@
 use crate::CheatnetState;
 use blockifier::execution::call_info::OrderedEvent;
 use cairo_felt::Felt252;
-use cairo_vm::hint_processor::hint_processor_utils::felt_to_usize;
 use conversions::{
     serde::{deserialize::CairoDeserialize, serialize::CairoSerialize},
     FromConv,
 };
 use starknet_api::core::ContractAddress;
-use std::mem::take;
 
 /// Represents an emitted event. It is used in the `CheatnetState` to keep track of events
 /// emitted in the `cheatnet::src::rpc::call_contract`
@@ -63,29 +61,7 @@ impl SpyTarget {
 }
 
 impl CheatnetState {
-    pub fn spy_events(&mut self, spy_on: SpyTarget) -> usize {
-        self.spies.push(spy_on);
-        self.spies.len() - 1
-    }
-
-    pub fn fetch_events(&mut self, id: &Felt252) -> Vec<Event> {
-        let spy_on = &self.spies[felt_to_usize(id).unwrap()];
-
-        // replace with empty to get ownership
-        let emitted_events = take(&mut self.detected_events);
-
-        emitted_events
-            .into_iter()
-            .filter_map(|event| {
-                if spy_on.does_spy(event.from) {
-                    Some(event)
-                } else {
-                    // push back unconsumed ones
-                    self.detected_events.push(event);
-
-                    None
-                }
-            })
-            .collect()
+    pub fn get_events(&mut self, event_offset: usize) -> Vec<Event> {
+        self.detected_events[event_offset..].to_vec()
     }
 }

crates/cheatnet/src/runtime_extensions/forge_runtime_extension/mod.rs

@@ -273,24 +273,23 @@ impl<'a> ExtensionLogic for ForgeExtension<'a> {
                 Ok(CheatcodeHandlingResult::Handled(parsed_content))
             }
             "spy_events" => {
-                let spy_on = input_reader.read()?;
-
-                let id = extended_runtime
+                let events_offset = extended_runtime
                     .extended_runtime
                     .extension
                     .cheatnet_state
-                    .spy_events(spy_on);
+                    .detected_events
+                    .len();
 
-                Ok(CheatcodeHandlingResult::from_serializable(id))
+                Ok(CheatcodeHandlingResult::from_serializable(events_offset))
             }
-            "fetch_events" => {
-                let id = input_reader.read()?;
+            "get_events" => {
+                let events_offset = input_reader.read()?;
 
                 let events = extended_runtime
                     .extended_runtime
                     .extension
                     .cheatnet_state
-                    .fetch_events(&id);
+                    .get_events(events_offset);
 
                 Ok(CheatcodeHandlingResult::from_serializable(events))
             }

crates/cheatnet/src/state.rs

@@ -4,9 +4,7 @@ use crate::runtime_extensions::call_to_blockifier_runtime_extension::rpc::CallRe
 use crate::runtime_extensions::forge_runtime_extension::cheatcodes::cheat_execution_info::{
     ExecutionInfoMock, ResourceBounds,
 };
-use crate::runtime_extensions::forge_runtime_extension::cheatcodes::spy_events::{
-    Event, SpyTarget,
-};
+use crate::runtime_extensions::forge_runtime_extension::cheatcodes::spy_events::Event;
 use blockifier::blockifier::block::BlockInfo;
 use blockifier::execution::call_info::OrderedL2ToL1Message;
 use blockifier::execution::entry_point::CallEntryPoint;
@@ -320,7 +318,6 @@ pub struct CheatnetState {
     pub mocked_functions:
         HashMap<ContractAddress, HashMap<EntryPointSelector, CheatStatus<Vec<StarkFelt>>>>,
     pub replaced_bytecode_contracts: HashMap<ContractAddress, ClassHash>,
-    pub spies: Vec<SpyTarget>,
     pub detected_events: Vec<Event>,
     pub deploy_salt_base: u32,
     pub block_info: BlockInfo,
@@ -341,7 +338,6 @@ impl Default for CheatnetState {
             global_cheated_execution_info: Default::default(),
             mocked_functions: Default::default(),
             replaced_bytecode_contracts: Default::default(),
-            spies: vec![],
             detected_events: vec![],
             deploy_salt_base: 0,
             block_info: SerializableBlockInfo::default().into(),

crates/cheatnet/tests/cheatcodes/cheat_caller_address.rs

@@ -3,9 +3,7 @@ use crate::common::get_contracts;
 use cairo_felt::Felt252;
 use cairo_lang_starknet_classes::keccak::starknet_keccak;
 use cheatnet::constants::TEST_ADDRESS;
-use cheatnet::runtime_extensions::forge_runtime_extension::cheatcodes::spy_events::{
-    Event, SpyTarget,
-};
+use cheatnet::runtime_extensions::forge_runtime_extension::cheatcodes::spy_events::Event;
 use cheatnet::state::CheatSpan;
 use conversions::IntoConv;
 use starknet_api::core::{ContractAddress, PatriciaKey};
@@ -306,7 +304,6 @@ fn cheat_caller_address_cairo0_callback() {
     let contract_address = test_env.deploy("Cairo1Contract_v1", &[]);
 
     test_env.start_cheat_caller_address(contract_address, 123);
-    let id = test_env.cheatnet_state.spy_events(SpyTarget::All);
 
     let expected_caller_address = Felt252::from(123);
 
@@ -326,7 +323,7 @@ fn cheat_caller_address_cairo0_callback() {
         &[],
     );
 
-    let events = test_env.cheatnet_state.fetch_events(&Felt252::from(id));
+    let events = test_env.cheatnet_state.get_events(0);
 
     // make sure end() was called by cairo0 contract
     assert_eq!(