create financial module (price plus tax)and tests

Author: alirezasariri78

Algorithms.Tests/Financial/PricePlusTaxTest.cs

@@ -0,0 +1,25 @@
+using Algorithms.Financial;
+using FluentAssertions;
+using NUnit.Framework;
+
+namespace Algorithms.Tests.Financial
+{
+    [TestFixture]
+
+    public class PricePlusTaxTest
+    {
+        [Test]
+        public void Price_Plus_Tax_Test()
+        {
+            PricePlusTax.Calculate(125.50m, 0.05m).Should().Be(131.775m);
+            PricePlusTax.Calculate(125.50f, 0.05f).Should().Be(131.775f);
+
+            PricePlusTax.Calculate(100.0m, 0.25m).Should().Be(125.0m);
+            PricePlusTax.Calculate(100.0f, 0.25f).Should().Be(125.0f);
+
+            PricePlusTax.Calculate(0, 0.25).Should().Be(0);
+            PricePlusTax.Calculate(0.0f, 0.25f).Should().Be(0.0f);
+            PricePlusTax.Calculate(0.0m, 0.25m).Should().Be(0.0m);
+        }
+    }
+}

Algorithms/Financial/PricePlusTax.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Numerics;
+
+namespace Algorithms.Financial
+{
+    public static class PricePlusTax
+    {
+        public static double Calculate(double price, double taxRate)
+        => price * (1 + taxRate);
+
+        public static decimal Calculate(decimal price, decimal taxRate)
+        => price * (1 + taxRate);
+
+        public static int Calculate(int price, int taxRate)
+        => price * (1 + taxRate);
+
+        public static float Calculate(float price, float taxRate)
+        => price * (1 + taxRate);
+    }
+}