feat: 實作圓形面積計算邏輯。調整測試個案中PI的小數進位問題。

AreaOfShapeCalulations/Circle.cs

@@ -0,0 +1,17 @@
+namespace AreaOfShapeCalulations
+{
+    public class Circle : IShape
+    {
+        private double _radius;
+
+        public Circle(double radius)
+        {
+            _radius = radius;
+        }
+
+        public double Area()
+        {
+            return Math.Round(Math.PI * _radius * _radius,2);
+        }
+    }
+}

AreaOfShapeCalulationsTests/CalculateAreaTests.cs

@@ -31,6 +31,15 @@ public void CalculateSquareArea()
             TotalAreaShouldBe(9, square);
         }
 
+        [TestMethod]
+        public void CalculateCircleArea()
+        {
+            //Arrange：準備測試資料(物件)
+            var circle = new Circle(4d);
+
+            TotalAreaShouldBe(50.27, circle);
+        }
+
         private void TotalAreaShouldBe(double expected, IShape shape)
         {
             //Act：用Calculator

README.md

@@ -70,7 +70,7 @@ Feature: Calculate the area of different shapes.
   Scenario: Calculate Circle
     Given There is a circle, and radius is 4 cm 
     When Calculate area
-    Then The area is 50.24 square cm
+    Then The area is 50.27 square cm
 
   Scenario: Calculate Triangle
     Given There is a triangle, height is 4 cm, and base-side is 5 cm