setup testing macros to print to stdout for test purposes

Author: scottgerring

opentelemetry/src/global/internal_logging.rs

@@ -4,6 +4,9 @@
 /// **internally within OpenTelemetry code** or for **custom exporters, processors and other plugins**. They are not designed
 /// for general application logging and should not be used for that purpose.
 ///
+/// When running tests with `--nocapture`, these macros will print their output to stdout. This is useful for debugging
+/// test failures and understanding the flow of operations during testing.
+///
 /// Macro for logging informational messages in OpenTelemetry.
 ///
 /// # Fields:
@@ -25,7 +28,13 @@ macro_rules! otel_info {
         {
             tracing::info!( name: $name, target: env!("CARGO_PKG_NAME"), name = $name, "");
         }
-        #[cfg(not(feature = "internal-logs"))]
+
+        #[cfg(test)]
+        {
+            print!("otel_info: name={}\n", $name);
+        }
+
+        #[cfg(all(not(feature = "internal-logs"), not(test)))]
         {
             let _ = $name; // Compiler will optimize this out as it's unused.
         }
@@ -35,7 +44,17 @@ macro_rules! otel_info {
         {
             tracing::info!(name: $name, target: env!("CARGO_PKG_NAME"), name = $name, $($key = $value),+, "");
         }
-        #[cfg(not(feature = "internal-logs"))]
+
+        #[cfg(test)]
+        {
+            print!("otel_info: name={}", $name);
+            $(
+                print!(", {}={}", stringify!($key), $value);
+            )+
+            print!("\n");
+        }
+
+        #[cfg(all(not(feature = "internal-logs"), not(test)))]
         {
             let _ = ($name, $($value),+); // Compiler will optimize this out as it's unused.
         }
@@ -60,7 +79,13 @@ macro_rules! otel_warn {
         {
             tracing::warn!(name: $name, target: env!("CARGO_PKG_NAME"), name = $name, "");
         }
-        #[cfg(not(feature = "internal-logs"))]
+
+        #[cfg(test)]
+        {
+            print!("otel_warn: name={}\n", $name);
+        }
+
+        #[cfg(all(not(feature = "internal-logs"), not(test)))]
         {
             let _ = $name; // Compiler will optimize this out as it's unused.
         }
@@ -77,7 +102,17 @@ macro_rules! otel_warn {
                             ""
                     )
         }
-        #[cfg(not(feature = "internal-logs"))]
+
+        #[cfg(test)]
+        {
+            print!("otel_warn: name={}", $name);
+            $(
+                print!(", {}={}", stringify!($key), $value);
+            )+
+            print!("\n");
+        }
+
+        #[cfg(all(not(feature = "internal-logs"), not(test)))]
         {
             let _ = ($name, $($value),+); // Compiler will optimize this out as it's unused.
         }
@@ -102,7 +137,13 @@ macro_rules! otel_debug {
         {
             tracing::debug!(name: $name, target: env!("CARGO_PKG_NAME"), name = $name, "");
         }
-        #[cfg(not(feature = "internal-logs"))]
+
+        #[cfg(test)]
+        {
+            print!("otel_debug: name={}\n", $name);
+        }
+        
+        #[cfg(all(not(feature = "internal-logs"), not(test)))]
         {
             let _ = $name; // Compiler will optimize this out as it's unused.
         }
@@ -112,7 +153,17 @@ macro_rules! otel_debug {
         {
             tracing::debug!(name: $name, target: env!("CARGO_PKG_NAME"), name = $name, $($key = $value),+, "");
         }
-        #[cfg(not(feature = "internal-logs"))]
+
+        #[cfg(test)]
+        {
+            print!("otel_debug: name={}", $name);
+            $(
+                print!(", {}={}", stringify!($key), $value);
+            )+
+            print!("\n");
+        }
+
+        #[cfg(all(not(feature = "internal-logs"), not(test)))]
         {
             let _ = ($name, $($value),+); // Compiler will optimize this out as it's unused.
         }
@@ -137,7 +188,13 @@ macro_rules! otel_error {
         {
             tracing::error!(name: $name, target: env!("CARGO_PKG_NAME"), name = $name, "");
         }
-        #[cfg(not(feature = "internal-logs"))]
+
+        #[cfg(test)]
+        {
+            print!("otel_error: name={}\n", $name);
+        }
+
+        #[cfg(all(not(feature = "internal-logs"), not(test)))]
         {
             let _ = $name; // Compiler will optimize this out as it's unused.
         }
@@ -154,7 +211,17 @@ macro_rules! otel_error {
                             ""
                     )
         }
-        #[cfg(not(feature = "internal-logs"))]
+
+        #[cfg(test)]
+        {
+            print!("otel_error: name={}", $name);
+            $(
+                print!(", {}={}", stringify!($key), $value);
+            )+
+            print!("\n");
+        }
+
+        #[cfg(all(not(feature = "internal-logs"), not(test)))]
         {
             let _ = ($name, $($value),+); // Compiler will optimize this out as it's unused.
         }