Add new tests to verify coverage diff

Author: bart-vmware

src/Common/src/Common/Calculator.cs

@@ -0,0 +1,18 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information.
+
+namespace Steeltoe.Common;
+
+public static class Calculator
+{
+    public static int Add(int first, int second)
+    {
+        return first + second;
+    }
+
+    public static int Subtract(int first, int second)
+    {
+        return first - second;
+    }
+}

src/Common/src/Common/PublicAPI.Unshipped.txt

@@ -1,4 +1,7 @@
 #nullable enable
+static Steeltoe.Common.Calculator.Add(int first, int second) -> int
+static Steeltoe.Common.Calculator.Subtract(int first, int second) -> int
+Steeltoe.Common.Calculator
 Steeltoe.Common.Discovery.IServiceInstance.InstanceId.get -> string!
 Steeltoe.Common.Discovery.IServiceInstance.NonSecureUri.get -> System.Uri?
 Steeltoe.Common.Discovery.IServiceInstance.SecureUri.get -> System.Uri?

src/Common/test/Common.Test/CalculatorTest.cs

@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information.
+
+namespace Steeltoe.Common.Test;
+
+public sealed class CalculatorTest
+{
+    [Fact]
+    public void CanAdd()
+    {
+        int result = Calculator.Add(2, 3);
+        result.Should().Be(5);
+    }
+
+    [Fact]
+    public void CanSubtract()
+    {
+        int result = Calculator.Subtract(5, 3);
+        result.Should().Be(2);
+    }
+}