Add unit test for ProcessInfo.

Author: haipz

test/Libraries/Microsoft.Extensions.Diagnostics.ResourceMonitoring.Tests/Windows/ProcessInfoTests.cs

@@ -0,0 +1,24 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.Extensions.Diagnostics.ResourceMonitoring.Windows.Interop;
+using Microsoft.TestUtilities;
+using Xunit;
+
+namespace Microsoft.Extensions.Diagnostics.ResourceMonitoring.Windows.Test;
+
+/// <summary>
+/// Process Info Interop Tests.
+/// </summary>
+/// <remarks>These tests are added for coverage reasons, but the code doesn't have
+/// the necessary environment predictability to really test it.</remarks>
+[OSSkipCondition(OperatingSystems.Linux | OperatingSystems.MacOSX, SkipReason = "Windows specific.")]
+public sealed class ProcessInfoTests
+{
+    [ConditionalFact]
+    public void GetCurrentProcessMemoryUsage()
+    {
+        var workingSet64 = new ProcessInfo().GetCurrentProcessMemoryUsage();
+        Assert.True(workingSet64 > 0);
+    }
+}