test(util): add a test_dbg! macro (#333)

This was cherry-picked out of PR #332

Author: hawkw

Cargo.lock

@@ -27,6 +27,9 @@ tracing = { git = "https://github.com/tokio-rs/tracing", default_features = fals
 [target.'cfg(loom)'.dependencies]
 loom = "0.5.5"
 
+[target.'cfg(loom)'.dev-dependencies]
+tracing_01 = { package = "tracing", version = "0.1.36" }
+
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]

util/Cargo.toml

@@ -66,3 +66,40 @@ macro_rules! unreachable_unchecked {
         }
     });
 }
+
+#[cfg(test)]
+macro_rules! test_dbg {
+    ($x:expr) => {
+        match $x {
+            x => {
+                test_trace!(
+                    location = %core::panic::Location::caller(),
+                    "{} = {x:?}",
+                    stringify!($x)
+                );
+                x
+            }
+        }
+    };
+}
+
+#[cfg(not(test))]
+macro_rules! test_dbg {
+    ($x:expr) => {
+        $x
+    };
+}
+
+#[cfg(all(test, not(loom)))]
+macro_rules! test_trace {
+    ($($arg:tt)+) => {
+        tracing::trace!($($arg)+);
+    };
+}
+
+#[cfg(all(test, loom))]
+macro_rules! test_trace {
+    ($($arg:tt)+) => {
+        tracing_01::trace!($($arg)+);
+    };
+}