kellsaro/genome_challenge_validations

Live Code Challenge

Write a program that validates a given input.

The validation criteria is the following.

The length of the string must be between 10 and 15 characters.
The string must include at least 3 numbers.
The string must include at least 4 uppercase characters.

When the criteria is not met, the program will throw a custom exception that has a message indicating the invalid criteria.

For example ,the string “too-short” will include the 3 messages.

[

  “The length of the input must be between 10 and 15 characters”,

  “The input must include at least 3 numbers”,

  “The input must include at least 4 uppercase characters”

]

We want a descriptive error message when the validation fails.

The code has to be implemented taking into account that the validation requirements may change over time.

We encourage you to write automated tests.

Solution

The proposed solution tries to mimic the way ActiveRecord::Validations works. This solution was implemented with Ruby 3.

Validator class hierarchy

Under Validator module there is a class hierarchy for describing different validators. Validator::Base class is the base class of the hierarchy and provides #validate method to be implemented in child classes.

For the sake of this exercise Validator::DigitsMinValidator, Validator::LengthInRangeValidator and Validator::UppercaseMinValidator are provided.

Validations module

For achieve this goal there is a Validations::Validatable module which add validate class method, and validate! instance method.

validate class method registers the attribute and the different validators to use depending on the validations.

validate! instance method run validations configured for each field and raise exception Validations::ValidationException with one or multiple error messages. The current implementation follows the description for this exercise and only includes the message, future implementations could include information on the field with the error.

There is a convention to be followed: When declaring a validation option, there should be a validator matching that option. Ex: for length_in_range the programs looks if exists a class in Validator module with the name LengthInRangeValidator.

Future versions could include other options for more flexibility.

Genome program

The class GenomeProgram includes the Validatable module and uses the validate class method for describing the validation on the input field. GenomeProgram instances has access to validate! method for runing validations.

require_relative './validations/validatable'

class GenomeProgram
  include Validations::Validatable

  attr_reader :input

  validate :input, length_in_range: (10..15), digits_min: 3, uppercase_min: 4

  def initialize(input)
    @input = input
  end
end

Test

Tests implemented in genome_program_test.rb file can be executed in a terminal using: ruby genome_program_test.rb. They cover the test for this exercise.

Those tests use Test::Unit Ruby framework.