Administering the Interview

###30 minutes, 50 possible points

Before beginning, make sure they understand that you assume from their resume that they are proficient in .NET, C#, SOLID design principles, unit testing, and at least one IoC Container

Scenario: A junior programmer created the following application, it needs to be finished and code reviewed.

1. Show the candidate ReverseEvenNumberGenerator and its unit test They may not change the for loop
   • (5 points) Have them finish the class so that the unit tests pass
   • (2 points) Single if-then-else statement
   • (2 points) don't concatenate strings to produce the result (string builder or string.Join)
   • (1 point) No extraneous lists or processing
   • (1 point) Style & readability
2. Have them perform a code review on Class1
   • (2 points) Identifies "SetRange" method as Sequential Coupling issue (must call as dependency initializer)
   • (2 points) Recommends Constructor Injection
   • (2 points) name the class something meaningful
   • (2 points) Recommends putting the range elements into another class
   • (2 points) Justifies another class because it can be injected by IoC container whereas integer primitives cannot.
   • (2 points) Recognizes extraneous loop in Generate Output based on putting items in a list and calling string.join
3. Show them OddNumberGenerator and the Extensions file.
   • Ask them how they would apply the provided interface and introduce a second implementation
     • (2 points) Make the class non-static
     • (2 points) Remove the "this" keyword from each method
     • (2 points) Remove the "static" keyword from each method
     • (2 points) Change the existing calls to be made from an instance of the object
   • Ask them what they would need to change to make the library a pluggable dependency
     • (2 points) Register the desired class in the IoC container & provide as dependency
4. Add the FizzBuzzGenerator to the program
   • Show them the program wrapper (program.cs)
   • Show them the FizzBuzzGenerator class, ask them what they need to do to add FizzBuzzGenerator functionality to the application and suggest improvements
     • (4 points) The switch statement used to create different classes is a code smell because it requrires changing every time a new class is registered or removed from IoC
     • (2 points) They suggest refactoring the switch statment using either an array of IGenerateOutput, or named registrations
   • Based on the different Generator classes dependency injection methods, describe how these classes would be registered using their IoC of choice, and suggest improvements
     • (2 points) Factory Methods and Create registrations are a code smell that means the classes themselves should be refactored
     • (2 points) Registrations should be performed by convention or automatically
5. Ask them to finish the code review by commenting on the unit tests
   • (1 point) Split tests into classes to mirror the classes being tested and common test setup conditions "When..."
   • (1 point) Rename test methods to follow a "Should..."
   • (2 points) Use a stub rather than private class
   • (2 points) Missing unit tests for FizzBuzzGenerator
   • (2 points) Missing unit tests for Range