Remove test_logger feature (#9125)

- #9107


  Remove all instances of `test_logger` in the code


Co-Authored-By: Tan Chee Keong <tanck@sigmaprime.io>

common/logging/Cargo.toml

@@ -4,12 +4,11 @@ version = "0.2.0"
 authors = ["blacktemplar <blacktemplar@a1.net>"]
 edition = { workspace = true }
 
-[features]
-# Print log output to stderr when running tests instead of dropping it.
-test_logger = []
-
 [dependencies]
-chrono = { version = "0.4", default-features = false, features = ["clock", "std"] }
+chrono = { version = "0.4", default-features = false, features = [
+    "clock",
+    "std",
+] }
 logroller = { workspace = true }
 metrics = { workspace = true }
 serde = { workspace = true }

common/logging/src/lib.rs

@@ -42,16 +42,15 @@ impl TimeLatch {
 
 /// Return a tracing subscriber suitable for test usage.
 ///
-/// By default no logs will be printed, but they can be enabled via
-/// the `test_logger` feature.  This feature can be enabled for any
-/// dependent crate by passing `--features logging/test_logger`, e.g.
+/// By default no logs will be printed, logs will be printed by using --nocapture. Example:
 /// ```bash
-/// cargo test -p beacon_chain --features logging/test_logger
+/// cargo test --release  -p beacon_chain -- --nocapture
 /// ```
 pub fn create_test_tracing_subscriber() {
-    if cfg!(feature = "test_logger") {
-        let _ = tracing_subscriber::fmt()
-            .with_env_filter(EnvFilter::try_new("debug").unwrap())
-            .try_init();
-    }
+    let _ = tracing_subscriber::fmt()
+        .with_test_writer()
+        .with_env_filter(
+            EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("debug")),
+        )
+        .try_init();
 }