Unit testing caveats

There is much controversy regarding test driven development. People do not seem to settle on the time trade-off, the London vs. State school, TDD vs BDD and the list could go on. But before diving into all of these, my first reports from the tranches of unit testing are as follows.

Behavior depending on date and time conditions

Tests should be runnable at any hour. Even if we leave the office at 6PM and everything seems to work properly, having loose DateTime variables in the tests could mean that they will fail during the automatic build that is run every night.

For example, we might want to ensure that our newsletter goes out only on Mondays. In this case, using an ICommand would make sense, because we can verify that our condition has been met before executing the action. A Command accepts a CanExecute Action that could like this one:

Func<Email, bool> canSendEmail = (email) =>
{
    if (email.DateToBeSent.DayOfWeek == DayOfWeek.Monday)
        return true;
    return false;
};

Working with WebViews in Xamarin.Android

Showing a webpage inside a Xamarin.Android app can be done using a WebView. Here are some tips.

Using Directives

Pop science says that more choices don’t bring more happiness. Well, yeah. Turns out you have two options for creating an URL. This was half of my problem.

An easier way of writing conditional code

I love attending code retreats. It’s an extremely efficient way to learn new things, though the people you pair with and the exercises you practice. And since keeping up with the newest thing is essential to a programmer, what better way to expand your knowledge is there than to let your creativity loose writing code in a different manner than the one you do every day?

What is a code kata?

A code kata is an exercise in programming which helps hone your skills through practice and repetition. Usually at code retreats, you pair with a different partner for each kata and you try to solve them by applying different pair programming techniques. Definitely my favorite kata so far is “Use no conditional blocks in your code”.

TeaTimer for Mac

This article will cover how to build a Mac application with Mono.Mac, making use of XCode interface builder and NSComboBoxDataSource. TeaTimer will let us chose a tea variety and it will the time how long it will take to make it.

Open Xamarin studio and start a new project. Select a Mono.Mac application.

Open the MainWindow.xib, which will be our main application window. This will start up XCode interface builder. From the Object library, drag and drop onto the existing window:

• a combo box, which will display our tea menu,
• a button, to start the timer,
• two labels: one for displaying the current time and one for additional information

Kaleidoscope Image Gallery

This recipe is written for the Xamarin iOS 7 Cook-off. The source code can be found here.

iOS 7 introduces a lot of new features. We will explore the gravity and collision behaviors the OS provides natively with its newest version, building a kaleidoscope image gallery.

Start by creating a new Xamarin.iOS project. Go to File > New > Solution. Select C# > iOS from the sidebar and then Single View Application. Name your application and Xamarin Studio will create for us a ViewController.