From 7bdf6f6fe8de1ea092c4cfea4ae44c7da2001aa4 Mon Sep 17 00:00:00 2001
From: teor <teor@riseup.net>
Date: Wed, 24 Jun 2020 18:18:43 +1000
Subject: [PATCH] consensus: Only initialise tracing once for the block tests

Part of #428.
---
 zebra-consensus/src/lib.rs          | 29 +++++++++++++++++++++++++++++
 zebra-consensus/src/verify/block.rs | 24 +++++++-----------------
 2 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/zebra-consensus/src/lib.rs b/zebra-consensus/src/lib.rs
index b0d513729b4..bf894937699 100644
--- a/zebra-consensus/src/lib.rs
+++ b/zebra-consensus/src/lib.rs
@@ -16,3 +16,32 @@
 pub mod checkpoint;
 pub mod mempool;
 pub mod verify;
+
+/// Test utility functions
+///
+/// Submodules have their own specific tests.
+#[cfg(test)]
+mod tests {
+    use std::sync::Once;
+    use tracing_error::ErrorLayer;
+    use tracing_subscriber::prelude::*;
+    use tracing_subscriber::{fmt, EnvFilter};
+
+    static LOGGER_INIT: Once = Once::new();
+
+    // TODO(jlusby): Refactor into the zebra-test crate (#515)
+    pub(crate) fn install_tracing() {
+        LOGGER_INIT.call_once(|| {
+            let fmt_layer = fmt::layer().with_target(false);
+            let filter_layer = EnvFilter::try_from_default_env()
+                .or_else(|_| EnvFilter::try_new("info"))
+                .unwrap();
+
+            tracing_subscriber::registry()
+                .with(filter_layer)
+                .with(fmt_layer)
+                .with(ErrorLayer::default())
+                .init();
+        })
+    }
+}
diff --git a/zebra-consensus/src/verify/block.rs b/zebra-consensus/src/verify/block.rs
index 17d609476a9..322bdfe3564 100644
--- a/zebra-consensus/src/verify/block.rs
+++ b/zebra-consensus/src/verify/block.rs
@@ -147,6 +147,7 @@ where
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::tests::install_tracing;
 
     use chrono::offset::{LocalResult, TimeZone};
     use chrono::{Duration, Utc};
@@ -288,26 +289,11 @@ mod tests {
         }
     }
 
-    fn install_tracing() {
-        use tracing_error::ErrorLayer;
-        use tracing_subscriber::prelude::*;
-        use tracing_subscriber::{fmt, EnvFilter};
-
-        let fmt_layer = fmt::layer().with_target(false);
-        let filter_layer = EnvFilter::try_from_default_env()
-            .or_else(|_| EnvFilter::try_new("info"))
-            .unwrap();
-
-        tracing_subscriber::registry()
-            .with(filter_layer)
-            .with(fmt_layer)
-            .with(ErrorLayer::default())
-            .init();
-    }
-
     #[tokio::test]
     #[spandoc::spandoc]
     async fn verify() -> Result<(), Report> {
+        install_tracing();
+
         let block =
             Arc::<Block>::zcash_deserialize(&zebra_test::vectors::BLOCK_MAINNET_415000_BYTES[..])?;
         let hash: BlockHeaderHash = block.as_ref().into();
@@ -331,6 +317,8 @@ mod tests {
     #[tokio::test]
     #[spandoc::spandoc]
     async fn round_trip() -> Result<(), Report> {
+        install_tracing();
+
         let block =
             Arc::<Block>::zcash_deserialize(&zebra_test::vectors::BLOCK_MAINNET_415000_BYTES[..])?;
         let hash: BlockHeaderHash = block.as_ref().into();
@@ -440,6 +428,8 @@ mod tests {
     #[tokio::test]
     #[spandoc::spandoc]
     async fn verify_fail_future_time() -> Result<(), Report> {
+        install_tracing();
+
         let mut block =
             <Block>::zcash_deserialize(&zebra_test::vectors::BLOCK_MAINNET_415000_BYTES[..])?;