Author: Chris F Carroll

Web Forms – Mocking HttpSession

With thanks to http://stackoverflow.com/users/603670/ben-barreth
at http://stackoverflow.com/questions/1981426/how-do-i-mock-fake-the-session-object-in-asp-net-web-forms

[SetUp]
public void SetUpHttpSessionMock()
{
HttpWorkerRequest _wr = new SimpleWorkerRequest("/dummyWorkerRequest", @"c:\inetpub\wwwroot\dummy", "default.aspx", null, new StringWriter());
HttpContext.Current = new HttpContext(_wr);
HttpSessionStateContainer sessionContainer = new HttpSessionStateContainer("id", new SessionStateItemCollection(), new HttpStaticObjectsCollection(), 10, true, HttpCookieMode.AutoDetect, SessionStateMode.InProc, false);
SessionStateUtility.AddHttpSessionStateToContext(HttpContext.Current, sessionContainer);
}

Refactoring a static class with hard-coded dependencies for testability

is not that hard. You can add a factory method to the static class to create the dependency, and change the factory method at test-time.
Here's an example:

public static class WithDependencies
{
	public static string MethodWithDependencies()
	{
		using (var thing = new HardCodedThing())
		{
			return DoSomething();
		}
	}
}

which can be turned into:

public static class WithDependencies
{
    public static Func<HardCodedThing> CreateHardCodedThing = () => new HardCodedThing();

	public static void MethodWithDependencies()
	{
		using (var thing = CreateHardCodedThing())
		{
			DoSomething();
		}
	}
}

With this code in your test:

[TestFixture]
public class WhenDoingSomething
{
	private Mock<HardCodedThing> mockThing;

	[SetUp]
	public void SetUpMockThing()
	{
		// mockThing.Setup( ...  ) ... etc ...
	}

	public void Given_hardcodedthing_does_X_should_get_Y()
	{
		//Arrange
		WithDependencies.CreateHardCodedThing = () => mockThing.Object;
		//Act
		var result= WithDependencies.MethodWithDependencies();
		//Assert
		Assert.AreEqual("Y", result);
	}
}

Code Kata One as Code – Supermarket Pricing

The code kata on supermarket pricing is one we wanted to do because we have some interest in pricing rules. However, it's written as a design exercise (which is a good thing), whereas we still wanted to do some coding.
So :

The Checkout Pricing Kata

Some things in supermarkets have simple prices: this can of beans costs £0.20. Other things have more complex prices. For example:
• three for a £ (so what’s the price if I buy 4, or 5?)
• £1.99/pound (so what does 4 ounces cost?)
• buy two, get one free (so does the third item have a price?)
Here's an example stock list with pricing and rules

Stock Pricing
Baked Beans: 20p per can, with a three-for-two offer.
Bananas: £1 per Kg
Bagged Bananas: £1.20 per bag
Beer: £1.50 per bottle, with a three-for-£4 offer
Bagels: £3 per dozen or £2.00 per half-dozen or 50p each
Kitchen Roll: 50p each
Beer 'n' Beans Cleanup Offer: Buy 3 cans of beans, 3 bottles of beer and get one free kitchen roll (not combinable with any other offer).
Beans 'n' Bagel Breakfast Offer: Get 6 cans of beans and a dozen bagels for £3.50 (not combinable with any other offer).

Checkout Pricing

Write something which, given a list of items purchased, will print out a priced and itemised receipt, with weights shown where relevant and all discount rules correctly applied. The customer should not be able to get a better price by re-organising or splitting up the shopping basket. The receipt should help the uncertain customer to see this.
In TDD style, do it by writing code to pass tests for a list of increasingly complex requirements.

Example shopping baskets

• 1 can of beans, and 1 bottle of beer
• 6 can of beans, and 3 bottles of beer
• 5 cans of beans and 1.4 kg of loose bananas
• 3kg of bananas and 7 bagels
• 4 cans of beans, 3 bottles of beer and a kitchen roll
• 10 cans of beans, 15 bagels, 4 bottles of beer, 2 kitchen rolls, 3.5 kg loose plus 1 bag of bananas.

I leave to the retail stategists amongst you the question, "Should it always be impossible for the customer to get a cheaper price by adding something to their basket?"

iPad printing problems

iPad printing is unreasonably difficult. It all works fine no doubt if you go out and buy a shiny new AirPrint enabled printer. Otherwise the simplest/cheapest thing I've found is:

I've had network problems too, similar to the problems with iTunes. Replacing my router was the best solution I had for that. If your router is old, or a very cheap broadband freebie, you may need to replace it.