Add a compilation flag to avoid recompiling aggregation programs on tests

Author: maximopalopoli

Makefile

@@ -252,6 +252,9 @@ proof_aggregator_start_dev: is_aggregator_set reset_last_aggregated_block ./aggr
 proof_aggregator_start_dev_ethereum_package: is_aggregator_set reset_last_aggregated_block ./aggregation_mode/target/release/proof_aggregator_dev ## Starts proof aggregator with mock proofs (DEV mode) in ethereum package. Parameters: AGGREGATOR=<sp1|risc0>
 	AGGREGATOR=$(AGGREGATOR) RISC0_DEV_MODE=1 ./aggregation_mode/target/release/proof_aggregator_dev config-files/config-proof-aggregator-mock-ethereum-package.yaml
 
+proof_aggregator_test_without_compiling_agg_programs:
+	cd aggregation_mode && SKIP_AGG_PROGRAMS_BUILD=1 cargo test -p proof_aggregator --tests -- --nocapture
+
 ### All CPU proof aggregator receipts
 ./aggregation_mode/target/release/proof_aggregator_cpu: $(AGGREGATION_MODE_SOURCES)
 	AGGREGATOR=$(AGGREGATOR) cargo build --features prove --manifest-path ./aggregation_mode/Cargo.toml --release --bin proof_aggregator_cpu

aggregation_mode/proof_aggregator/build.rs

@@ -1,8 +1,29 @@
 use risc0_build::{DockerOptionsBuilder, GuestOptionsBuilder};
 use std::collections::HashMap;
+use std::path::PathBuf;
 
 // Reference: https://docs.succinct.xyz/docs/sp1/writing-programs/compiling#advanced-build-options-1
 fn main() {
+    // This allows us to skip the guest build in CI or local environments where it's not needed (reducing the build time)
+    // Note: To use this flag, the aggregation programs should be already compiled, otherwise the compilation will be done anyway.
+    if std::env::var("SKIP_AGG_PROGRAMS_BUILD")
+        .map(|v| v == "1")
+        .unwrap_or(false)
+    {
+        let out_dir = std::env::var("OUT_DIR").unwrap();
+        let methods_path = PathBuf::from(out_dir).join("methods.rs");
+
+        if methods_path.exists() {
+            println!("cargo:warning=SKIP_AGG_PROGRAMS_BUILD=1: methods.rs already exists, skipping aggregation programs build");
+            return;
+        } else {
+            println!(
+                "cargo:warning=SKIP_AGG_PROGRAMS_BUILD=1 set, but {path} does not exist, running full build",
+                path = methods_path.display()
+            );
+        }
+    }
+
     sp1_build::build_program_with_args("./aggregation_programs/sp1", {
         sp1_build::BuildArgs {
             output_directory: Some("./aggregation_programs/sp1/elf".to_string()),