From 97ad06697ff0f88771ff1fbf2e9922a2ba54a198 Mon Sep 17 00:00:00 2001
From: Morgen Peschke <morgen.peschke@gmail.com>
Date: Tue, 25 Jun 2024 15:12:31 -0700
Subject: [PATCH] Add test explicitly demonstrating MDC behavior

---
 .../slf4j/internal/Slf4jLoggerInternalSuite.scala   | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/slf4j/src/test/scala/org/typelevel/log4cats/slf4j/internal/Slf4jLoggerInternalSuite.scala b/slf4j/src/test/scala/org/typelevel/log4cats/slf4j/internal/Slf4jLoggerInternalSuite.scala
index db09ca75..976dec24 100644
--- a/slf4j/src/test/scala/org/typelevel/log4cats/slf4j/internal/Slf4jLoggerInternalSuite.scala
+++ b/slf4j/src/test/scala/org/typelevel/log4cats/slf4j/internal/Slf4jLoggerInternalSuite.scala
@@ -141,6 +141,19 @@ class Slf4jLoggerInternalSuite extends CatsEffectSuite {
         )
   }
 
+  testLoggerFixture().test("Slf4jLoggerInternal ignores(?) values already in the MDC") { testLogger =>
+    IO.delay(MDC.put("baz", "bar")) >>
+      Slf4jLogger.getLoggerFromSlf4j[IO](testLogger).info(Map("foo" -> "bar"))("A log went here") >>
+      IO(testLogger.logs())
+        .map(toDeferredLogs)
+        .assertEquals(
+          List(
+            DeferredLogMessage.info(Map("foo" -> "bar"), none, () => "A log went here")
+          ),
+          clue("Context should not include baz->bar")
+        )
+  }
+
   testLoggerFixture(
     traceEnabled = false,
     debugEnabled = false,