The code provided is a class library vs an exectuable app. You will need units tests to verify your refactored code works.
computer science
Description
Advanced .Net Development with C#
Homework Assignment # 3
⦁ Single Responsibility Principle (SRP)
⦁ Refractor the order class (order.cs) to comply with SRP. Project is provided in HW3EX1B4.zip
⦁ The code provided is a class library vs an exectuable app. You will need units tests to verify your refactored code works. Create a separate project (HW3EX1.Tests) and write unit tests for your all classes in your refectored solution.
⦁ Screencast code walkthrough
⦁ Talk me through how the original code violated SRP. There are multiple reasons.
⦁ Talk me through your strategy to make the code SRP compliant.
⦁ Talk me through your unit tests and show me that they pass.
Hints:
⦁ Cash Transactions don’t need credit card processing
⦁ Point of Sale (POS) transactions don’t need inventory reservations
⦁ POS transactions don’t need email notifications
⦁ Any change in notifications, credit card processing, or inventory management will affect Order as well as the Web and POS implementations.
⦁ Open Closed Principle (OCP)
⦁ Refractor the cart class (cart.cs) to comply with OCP. Project is provided in HW3EX2B4.zip
⦁ The code provided is a class library vs an exectuable app. You will need units tests to verify your refactored code works. Create a separate project (HW3EX2.Tests) and write unit tests for your all classes in your refectored solution
⦁ Screencast code walkthrough
⦁ Talk me through how the original code violated OCP. There are multiple reasons.
⦁ Talk me through your strategy to make the code OCPP compliant.
⦁ Talk me through your unit tests and show me that they pass.
Hints:
⦁ Adding new rules require changed to the calculator every time
⦁ Each change can introduce bugs and requires re-testing etc.
⦁ We ant to avoid introducing changes that cascade through many modules in our application
⦁ Writing new classes is less likely to introduce problems
⦁ Nothing depends on new classes
⦁ New classes have no legacy coupling to make them hard to design or test
⦁ Liskov Substitution Principle (LSP)
⦁ States that subtypes(child classes) must be substitutable for base types (parent classes)
⦁ This unit test fails public void TwentyFor4X5RectangleFromSquare() in the attached code file (HW3EX3Code.txt).
⦁ AreaCalculator, Rectangle, and Square classes are below the test methods.
⦁ Rework the classes and make them honor LSP and pass all unit tests.
⦁ You may not change any of the code in the unit tests.
Hints:
⦁ Non-substitutable code breaks polymorphism
⦁ Client code expects child classes to work in place of their base classes
⦁ “fixing” substitutability problems by added if-then or swith statements quickly becomes a maintenance nightmare (and violates OCP).
⦁ Your solution should pass the following additional unit tests
[TestMethod]
public void TwentyFor4X5ShapeFromRectangle()
{
Shape myShape = new Rectangle(){Height = 4, Width = 5};
Assert.AreEqual(20, myShape.Area());
}
[TestMethod]
public void TwentyFor4X5ShapeFromRectangleAnd9For3X3Square()
{
var shapes = new List<Shape>
{
new Rectangle {Height = 4, Width = 5},
new Square {SideLength = 3}
};
var areas = new List<int>();
foreach (Shape shape in shapes)
{
areas.Add(shape.Area());
}
Assert.AreEqual(20, areas[0]);
Assert.AreEqual(9, areas[1]);
}
