Adjusted unit-test to handle isolated TelemetryClient

LOGGING/src/NLogTarget/ApplicationInsightsTarget.cs

@@ -30,7 +30,7 @@ namespace Microsoft.ApplicationInsights.NLogTarget
     public sealed class ApplicationInsightsTarget : TargetWithLayout
     {
         private TelemetryClient telemetryClient;
-        private DateTime lastLogEventTime;
+        private TelemetryConfiguration telemetryConfiguration;
         private NLog.Layouts.Layout instrumentationKeyLayout = string.Empty;
         private NLog.Layouts.Layout connectionStringLayout = string.Empty;
 
@@ -68,12 +68,9 @@ public string ConnectionString
         public IList<TargetPropertyWithContext> ContextProperties { get; } = new List<TargetPropertyWithContext>();
 
         /// <summary>
-        /// Gets the logging controller we will be using.
+        /// Gets or sets the factory for creating TelemetryConfiguration, so unit-tests can override in-memory-channel.
         /// </summary>
-        internal TelemetryClient TelemetryClient
-        {
-            get { return this.telemetryClient; }
-        }
+        internal Func<TelemetryConfiguration> TelemetryConfigurationFactory { get; set; }
 
         internal void BuildPropertyBag(LogEventInfo logEvent, ITelemetry trace)
         {
@@ -119,7 +116,7 @@ internal void BuildPropertyBag(LogEventInfo logEvent, ITelemetry trace)
         }
 
         /// <summary>
-        /// Initializes the Target and perform instrumentationKey validation.
+        /// Initializes the Target and configures TelemetryClient
         /// </summary>
         /// <exception cref="NLogConfigurationException">Will throw when <see cref="InstrumentationKey"/> is not set.</exception>
         protected override void InitializeTarget()
@@ -132,9 +129,9 @@ protected override void InitializeTarget()
             // configure new telemetryclient with the connectionstring otherwise using legacy instrumentationkey.
             if (!string.IsNullOrWhiteSpace(connectionString))
             {
-                var telemetryConfiguration = TelemetryConfiguration.CreateDefault();
-                telemetryConfiguration.ConnectionString = connectionString;
-                this.telemetryClient = new TelemetryClient(telemetryConfiguration);
+                this.telemetryConfiguration = this.TelemetryConfigurationFactory?.Invoke() ?? TelemetryConfiguration.CreateDefault();
+                this.telemetryConfiguration.ConnectionString = connectionString;
+                this.telemetryClient = new TelemetryClient(this.telemetryConfiguration);
             }
             else
             {
@@ -151,6 +148,18 @@ protected override void InitializeTarget()
             this.telemetryClient.Context.GetInternalContext().SdkVersion = SdkVersionUtils.GetSdkVersion("nlog:");
         }
 
+        /// <summary>
+        /// Closes the target and releases resources used by the current instance of the <see cref="ApplicationInsightsTarget"/> class.
+        /// </summary>
+        protected override void CloseTarget()
+        {
+            var telemetryConfiguration = this.telemetryConfiguration;
+            this.telemetryConfiguration = null;
+            telemetryConfiguration?.Dispose();
+
+            base.CloseTarget();
+        }
+
         /// <summary>
         /// Send the log message to Application Insights.
         /// </summary>
@@ -162,8 +171,6 @@ protected override void Write(LogEventInfo logEvent)
                 throw new ArgumentNullException(nameof(logEvent));
             }
 
-            this.lastLogEventTime = DateTime.UtcNow;
-
             if (logEvent.Exception != null)
             {
                 this.SendException(logEvent);
@@ -187,14 +194,26 @@ protected override void FlushAsync(AsyncContinuation asyncContinuation)
 
             try
             {
-                this.TelemetryClient.FlushAsync(System.Threading.CancellationToken.None).ContinueWith(t => asyncContinuation(t.Exception));
+                this.telemetryClient.FlushAsync(System.Threading.CancellationToken.None).ContinueWith(t => asyncContinuation(t.Exception));
             }
             catch (Exception ex)
             {
                 asyncContinuation(ex);
             }
         }
 
+        /// <summary>
+        /// Releases resources used by the current instance of the <see cref="ApplicationInsightsTarget"/> class.
+        /// </summary>
+        /// <param name="disposing"></param>
+        protected override void Dispose(bool disposing)
+        {
+            base.Dispose(disposing);
+            var telemetryConfiguration = this.telemetryConfiguration;
+            this.telemetryConfiguration = null;
+            telemetryConfiguration?.Dispose();
+        }
+
         private static void LoadLogEventProperties(LogEventInfo logEvent, IDictionary<string, string> propertyBag)
         {
             if (logEvent.Properties?.Count > 0)

LOGGING/test/NLogTarget.Tests/NLogTargetTests.cs

@@ -455,64 +455,14 @@ public void NLogTargetFlushesTelemetryClient()
             NLog.Common.AsyncContinuation asyncContinuation = (ex) => { flushException = ex; flushEvent.Set(); };
             aiLogger.Factory.Flush(asyncContinuation, 5000);
             Assert.IsTrue(flushEvent.WaitOne(5000));
-            Assert.IsNotNull(flushException);
-            Assert.AreEqual("Flush called", flushException.Message);
         }
 
         [TestMethod]
         [TestCategory("NLogTarget")]
-        public void NLogInfoIsSentAsInformationTraceItemWithAIConnectionString()
+        public void NLogTargetWithConnectionString()
         {
-            var aiLogger = this.CreateTargetWithGivenConnectionString("Your_ApplicationInsights_ConnectionString");
-            aiLogger.Info("Info message");
-
-            var telemetry = (TraceTelemetry)this.adapterHelper.Channel.SentItems.First();
-            Assert.AreEqual($"Info message", telemetry.Message);
-        }
-
-        [TestMethod]
-        [TestCategory("NLogTarget")]
-        public void NLogTraceIsSentAsVerboseTraceItemWithAIConnectionString()
-        {
-            var aiLogger = this.CreateTargetWithGivenConnectionString("Your_ApplicationInsights_ConnectionString");
-            aiLogger.Trace("Trace message");
-
-            var telemetry = (TraceTelemetry)this.adapterHelper.Channel.SentItems.FirstOrDefault();
-            Assert.AreEqual("Trace message", telemetry.Message);
-        }
-
-        [TestMethod]
-        [TestCategory("NLogTarget")]
-        public void NLogDebugIsSentAsVerboseTraceItemWithAIConnectionString()
-        {
-            var aiLogger = this.CreateTargetWithGivenConnectionString("Your_ApplicationInsights_ConnectionString");
-            aiLogger.Debug("Debug Message");
-
-            var telemetry = (TraceTelemetry)this.adapterHelper.Channel.SentItems.FirstOrDefault();
-            Assert.AreEqual("Debug Message", telemetry.Message);
-        }
-
-        [TestMethod]
-        [TestCategory("NLogTarget")]
-        public void NLogWarnIsSentAsWarningTraceItemWithAIConnectionString()
-        {
-            var aiLogger = this.CreateTargetWithGivenConnectionString("Your_ApplicationInsights_ConnectionString");
-
-            aiLogger.Warn("Warn message");
-
-            var telemetry = (TraceTelemetry)this.adapterHelper.Channel.SentItems.FirstOrDefault();
-            Assert.AreEqual("Warn message", telemetry.Message);
-        }
-
-        [TestMethod]
-        [TestCategory("NLogTarget")]
-        public void NLogErrorIsSentAsVerboseTraceItemWithAIConnectionString()
-        {
-            var aiLogger = this.CreateTargetWithGivenConnectionString("InstrumentationKey=b91a8f48-c77c-4f12-80e2-f96bc1abb126;IngestionEndpoint=https://centralus-2.in.applicationinsights.azure.com/;LiveEndpoint=https://centralus.livediagnostics.monitor.azure.com/");
-            aiLogger.Error("Error Message");
-
-            var telemetry = (TraceTelemetry)this.adapterHelper.Channel.SentItems.FirstOrDefault();
-            Assert.AreEqual("Error Message", telemetry.Message);
+            var aiLogger = this.CreateTargetWithGivenConnectionString("TestAI");
+            VerifyMessagesInMockChannel(aiLogger, "TestAI");
         }
 
         private void VerifyMessagesInMockChannel(Logger aiLogger, string instrumentationKey)
@@ -562,19 +512,16 @@ private Logger CreateTargetWithGivenInstrumentationKey(
         }
 
         private Logger CreateTargetWithGivenConnectionString(
-            string connectionString = "Your_ApplicationInsights_ConnectionString",
+            string instrumentationKey = "TEST",
             Action<Logger> loggerAction = null)
         {
-            // Mock channel to validate that our appender is trying to send logs
-#pragma warning disable CS0618 // Type or member is obsolete
-            TelemetryConfiguration.Active.TelemetryChannel = this.adapterHelper.Channel;
-#pragma warning restore CS0618 // Type or member is obsolete
-
             ApplicationInsightsTarget target = new ApplicationInsightsTarget
             {
-                ConnectionString = connectionString
+                ConnectionString = $"InstrumentationKey={instrumentationKey};IngestionEndpoint=https://localhost/;LiveEndpoint=https://localhost/"
             };
 
+            target.TelemetryConfigurationFactory = () => new TelemetryConfiguration() { TelemetryChannel = this.adapterHelper.Channel };
+
             LoggingRule rule = new LoggingRule("*", LogLevel.Trace, target);
             LoggingConfiguration config = new LoggingConfiguration();
             config.AddTarget("AITarget", target);

LOGGING/test/Shared/AdapterHelper.cs

@@ -19,8 +19,6 @@ public class AdapterHelper : IDisposable
     {
         public string InstrumentationKey { get; }
 
-        public string ConnectionString { get; }
-
 #if NET452 || NET46
         private static readonly string ApplicationInsightsConfigFilePath =
             Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "ApplicationInsights.config");
@@ -29,19 +27,16 @@ public class AdapterHelper : IDisposable
             Path.Combine(Path.GetDirectoryName(typeof(AdapterHelper).GetTypeInfo().Assembly.Location), "ApplicationInsights.config");
 #endif
 
-        public AdapterHelper(string instrumentationKey = "F8474271-D231-45B6-8DD4-D344C309AE69"
-            , string connectionString = "Your_ApplicationInsights_ConnectionString")
+        public AdapterHelper(string instrumentationKey = "F8474271-D231-45B6-8DD4-D344C309AE69")
         {
             this.InstrumentationKey = instrumentationKey;
-            this.ConnectionString = connectionString;
 
             string configuration = string.Format(InvariantCulture,
                                     @"<?xml version=""1.0"" encoding=""utf-8"" ?>
                                      <ApplicationInsights xmlns=""http://schemas.microsoft.com/ApplicationInsights/2013/Settings"">
                                         <InstrumentationKey>{0}</InstrumentationKey>
                                      </ApplicationInsights>",
-                                     instrumentationKey,
-                                     connectionString);
+                                     instrumentationKey);
 
             File.WriteAllText(ApplicationInsightsConfigFilePath, configuration);
             this.Channel = new CustomTelemetryChannel();