BFT-457: Separate logging init

node/actors/bft/src/tests.rs

@@ -254,9 +254,7 @@ async fn twins_network_w2_twins_w_partitions() {
 #[tokio::test(flavor = "multi_thread")]
 #[should_panic]
 async fn twins_network_to_fail() {
-    run_twins(5, 1, 100)
-        .await
-        .expect_err("will fail with assert");
+    run_twins(5, 1, 100).await.unwrap();
 }
 
 /// Create network configuration for a given number of replicas and twins and run [Test].
@@ -270,10 +268,10 @@ async fn run_twins(
 
     // If we pass more twins than tolerable faulty replicas then it should fail with an assertion error,
     // but if we abort the process on panic then the #[should_panic] attribute doesn't work with `cargo nextest`.
-    // Unfortunately this also turns off logging, but it's fine this is just to make sure Twins catch _something_.
     if num_twins <= max_faulty {
         zksync_concurrency::testonly::abort_on_panic();
     }
+    zksync_concurrency::testonly::init_tracing();
 
     let ctx = &ctx::test_root(&ctx::AffineClock::new(10.0));
     // Use a single timeout for all scenarios to finish.

node/libs/concurrency/src/testonly.rs

@@ -9,12 +9,7 @@ use std::{future::Future, io::IsTerminal as _};
 // TODO: investigate whether "-Zpanic-abort-tests" could replace this function once the flag
 // becomes stable: https://github.com/rust-lang/rust/issues/67650, so we don't use it.
 pub fn abort_on_panic() {
-    let _ = tracing_subscriber::fmt()
-        .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
-        .with_test_writer()
-        .with_ansi(std::env::var("NO_COLOR").is_err() && std::io::stdout().is_terminal())
-        .with_line_number(true)
-        .try_init();
+    init_tracing();
 
     // I don't know a way to set panic=abort for nextest builds in compilation time, so we set it
     // in runtime. https://nexte.st/book/env-vars.html#environment-variables-nextest-sets
@@ -35,6 +30,18 @@ pub fn abort_on_panic() {
     }));
 }
 
+/// Set up a tracing subscriber.
+///
+/// Use `RUST_LOG=info` to see the logs in testing.
+pub fn init_tracing() {
+    let _ = tracing_subscriber::fmt()
+        .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
+        .with_test_writer()
+        .with_ansi(std::env::var("NO_COLOR").is_err() && std::io::stdout().is_terminal())
+        .with_line_number(true)
+        .try_init();
+}
+
 /// Guard which has to be dropped before timeout is reached.
 /// Otherwise the test will panic.
 #[allow(dead_code)]