mariojvargas / sa-exercise

SA-EXERCISE

Technologies used

• .NET Core 3.1.302
• Console application
• LINQ

Tools used

• Visual Studio Code 1.42.1 for Mac OS
• EditorConfig

Patterns in use

• Factory
• Command
• Repository (ad hoc implementation)
• ViewModel
• Mediator
  • The TripCommandOrchestrator uses an ad hoc version of the Mediator pattern.
  • I would have used MediatR to dispatch the command as actions and have a separate command/handler class operate on the given CommandToken.

Challenges

• The requirement "Discard any trips that average a speed of less than 5 mph or greater than 100 mph" was not immediately clear to me.
  • I was not sure whether we were excluding trip speeds of less than 5 MPH or over 100 MPH since the example provided did not showcase this scenario. In addition, this requirement doesn't explain why Bob appears in the results since there are no trip entries for him.
  • I tried asking recruiter for clarification but my email was not answered in time.
• I am getting inconsistent results for Dan in example file.
  • The expected output for Dan is:
    • Dan: 39 miles @ 47 mph
  • However, my calculations for the average speed is off by 3. I even did this by hand and derived the same calculation (Average speed for Dan is 50):
    • Dan: 39 miles @ 50 mph
  • I tried manipulating the distances read in and calculated speeds by obtaining the floor value (Math.Floor()) but the least I got was 48 mph.
  • Having someone to talk to for clarification would have helped me to understand what I was missing.
  • This is just an example of unclear requirements. In a real world situation, I would have spoken with the BA to understand the requirements and possibly worked with a tester during a 3-Amigo session to derive test cases or identify missing scenarios/edge cases.

What I would do differently

• Implement dependency injection.
• Use asynchronous methods.
• Organize solution into multiple projects:
  • Core
  • Infrastructure
  • Data
  • Main (console app)
  • etc.
• Organize files into folders (models, repositories, services, etc.).
• Add error handling logic.
• Refactor Driver Repository to use Entity Framework Core with an in-memory database.
• Add unit tests.
• Improve TripFileTokenizer so that it is testable.

Executing

From the solution root:

$ dotnet run --project ./src/Mjv.TripReportGenerator

When prompted for the file name, enter

example-trip.txt

Example execution

Enter path to trip file:
example-trip.txt
You entered: example-trip.txt

REPORT:
=======
Alex: 42 miles @ 34 mph
Dan: 39 miles @ 50 mph
Bob: 0 miles