From f6bc94add4b85313101cbaf74af720566bdfad0f Mon Sep 17 00:00:00 2001
From: Sung Yoon Whang <suwhang@microsoft.com>
Date: Wed, 12 Feb 2020 18:19:43 -0800
Subject: [PATCH] Add test for null EventName in FormattedMessage event

---
 .../test/EventSourceLoggerTest.cs             | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/Logging/Logging.EventSource/test/EventSourceLoggerTest.cs b/src/Logging/Logging.EventSource/test/EventSourceLoggerTest.cs
index 3bc88a7b49e..9511c6306bb 100644
--- a/src/Logging/Logging.EventSource/test/EventSourceLoggerTest.cs
+++ b/src/Logging/Logging.EventSource/test/EventSourceLoggerTest.cs
@@ -427,6 +427,35 @@ public void Logs_Nothing_AfterDispose()
             }
         }
 
+        [Fact]
+        public void Logs_AsExpected_FormattedMessage_WithNullString()
+        {
+            using (var testListener = new TestEventListener())
+            {
+                var factory = CreateLoggerFactory();
+
+                var listenerSettings = new TestEventListener.ListenerSettings();
+                listenerSettings.Keywords = LoggingEventSource.Keywords.FormattedMessage;
+                listenerSettings.FilterSpec = null;
+                listenerSettings.Level = EventLevel.Verbose;
+                testListener.EnableEvents(listenerSettings);
+
+                LogStuff(factory);
+
+                var containsNullEventName = false;
+
+                foreach (var eventJson in testListener.Events)
+                {
+                    if (eventJson.Contains(@"""__EVENT_NAME"":""FormattedMessage""") && eventJson.Contains(@"""EventName"":"""","))
+                    {
+                        containsNullEventName = true;
+                    }
+                }
+
+                Assert.True(containsNullEventName, "EventName is supposed to be null but it isn't.");
+            }
+        }
+
         private void LogStuff(ILoggerFactory factory)
         {
             var logger1 = factory.CreateLogger("Logger1");