Create unit tests for Calculator plugin (#6356)

* Refactored logic and made it unit testable

* Changes after code review

* Added to build steps, and modified bracket to new class with unittest. Validates complexer cases now.

Co-authored-by: p-storm <paul.de.man@gmail.com>

src/modules/launcher/Plugins/Microsoft.Plugin.Calculator/CalculateResult.cs

@@ -0,0 +1,41 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Generic;
+
+namespace Microsoft.Plugin.Calculator
+{
+    public struct CalculateResult : IEquatable<CalculateResult>
+    {
+        public decimal Result { get; set; }
+
+        public decimal RoundedResult { get; set; }
+
+        public bool Equals(CalculateResult other)
+        {
+            return Result == other.Result && RoundedResult == other.RoundedResult;
+        }
+
+        public override bool Equals(object obj)
+        {
+            return obj is CalculateResult other && Equals(other);
+        }
+
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(Result, RoundedResult);
+        }
+
+        public static bool operator ==(CalculateResult left, CalculateResult right)
+        {
+            return left.Equals(right);
+        }
+
+        public static bool operator !=(CalculateResult left, CalculateResult right)
+        {
+            return !(left == right);
+        }
+    }
+}