Development Experience(s)

Let's hammer out some code! The above code looks fine and reads nicely - "if we don't have any app settings key called HttpBaseUrlSettingsKey , ... throw a configuration errors exception that explains what's wrong". In reality, however, what comes out, is an  ArgumentNullException  - AppSettings.Get returns null if it cannot find the requested key. This might not be so bad if you're consuming this code from the same solution. However, in a dependent solution, you get very sparse information about what went wrong: Not quite as nice as the intended "Missing keys ' HttpBaseUrlSettingsKey ' ... in appSettings element" message. A correct implementation in this case could look like this: However , the moral of this story is: Love your error conditions and test them. Don't just run down the happy path, leaving your carefully crafted checks behind!