[FEAT] Validation Helper (#33)

* feat: add validation helper

* test: add test coverage for validation helper

* chore: rename 'Errors' dir to 'errors'

app/errors/validation_error.rb

@@ -0,0 +1,11 @@
+##
+# Base class for a validation error.
+class ValidationError < StandardError
+  ##
+  # Constructor for error.
+  #
+  # @param message the error message (defaults to "Validation Error").
+  def initialize(message="Validation Error")
+    super(message)
+  end
+end

app/helpers/canvas_validation_helper.rb

@@ -0,0 +1,63 @@
+module CanvasValidationHelper
+  OVERRIDE_TITLE_MAX_CHARACTERS = 40
+
+  ##
+  # Checks if the provided course id is valid.
+  #
+  # @param [Integer] courseId the course id to check.
+  # @return [Boolean] whether the provided id is valid.
+  def is_valid_course_id(courseId)
+    courseId.is_a?(Integer) && courseId > 0
+  end
+
+  ##
+  # Checks if the provided assignment id is valid.
+  #
+  # @param [Integer] assignmentId the assignment id to check.
+  # @return [Boolean] whether the assignment id is valid.
+  def is_valid_assignment_id(assignmentId)
+    assignmentId.is_a?(Integer) && assignmentId > 0
+  end
+
+  ##
+  # Checks if the student id is valid.
+  #
+  # @param [Integer] studentId the student id to check.
+  # @return [Boolean] whether the student id is valid.
+  def is_valid_student_id(studentId)
+    studentId.is_a?(Integer) && studentId > 0
+  end
+
+  ##
+  # Checks if the list of student ids is valid.
+  #
+  # @param [Enumerable] the list of student ids to validate.
+  # @return [Boolean] whether all student ids in the list are valid.
+  def is_valid_student_ids(studentIds)
+    studentIds.all? do |studentId|
+      is_valid_student_id(studentId)
+    end
+  end
+
+  ##
+  # Checks to see if the provided override title is valid.
+  #
+  # @param [String] title the title to check.
+  # @return [Boolean] whether the title is valid.
+  def is_valid_title(title)
+    /^[A-Za-z0-9\-_ ]*$/.match?(title) && title.length < OVERRIDE_TITLE_MAX_CHARACTERS
+  end
+
+  ##
+  # Checks whether the provided date is a valid Canvas date.
+  # TODO: maybe want to refine this to actually valid dates not just format?
+  #
+  # @param [String] date the date string to validate.
+  # @return [Boolean] whether the date string is valid.
+  def is_valid_date(date)
+    if (date == nil)
+      return true
+    end
+    /^[0-9]{4}\-[0-9]{2}\-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}Z$/.match?(date)
+  end
+end

spec/Helpers/canvas_validation_helper_spec.rb

@@ -0,0 +1,112 @@
+require 'rails_helper'
+require_relative '../../app/helpers/canvas_validation_helper'
+
+describe 'CanvasValidationHelper', type: :helper do
+  class Helper
+    include CanvasValidationHelper
+  end
+  attr_reader :helper
+
+  before do
+    @helper = Helper.new
+  end
+
+  describe 'is_valid_course_id' do
+    it 'returns true on positive integer input' do
+      expect(helper.is_valid_course_id(16)).to be(true)
+    end
+
+    it 'returns false on negative integer input' do
+      expect(helper.is_valid_course_id(-16)).to be(false)
+    end
+
+    it 'returns false on boolean input' do
+      expect(helper.is_valid_course_id(0.1)).to be(false)
+    end
+
+    it 'returns false on alphabetical input' do
+      expect(helper.is_valid_course_id('abc')).to be(false)
+    end
+  end
+
+  describe 'is_valid_assignment_id' do
+    it 'returns true on positive integer input' do
+      expect(helper.is_valid_assignment_id(16)).to be(true)
+    end
+
+    it 'returns false on negative integer input' do
+      expect(helper.is_valid_assignment_id(-16)).to be(false)
+    end
+
+    it 'returns false on boolean input' do
+      expect(helper.is_valid_assignment_id(0.1)).to be(false)
+    end
+
+    it 'returns false on alphabetical input' do
+      expect(helper.is_valid_assignment_id('abc')).to be(false)
+    end
+  end
+
+  describe 'is_valid_student_id' do
+    it 'returns true on positive integer input' do
+      expect(helper.is_valid_student_id(16)).to be(true)
+    end
+
+    it 'returns false on negative integer input' do
+      expect(helper.is_valid_student_id(-16)).to be(false)
+    end
+
+    it 'returns false on boolean input' do
+      expect(helper.is_valid_student_id(0.1)).to be(false)
+    end
+
+    it 'returns false on alphabetical input' do
+      expect(helper.is_valid_student_id('abc')).to be(false)
+    end
+  end
+
+  describe 'is_valid_student_ids' do
+    it 'returns true on positive integral input' do
+      expect(helper.is_valid_student_ids([16, 18])).to be(true)
+    end
+
+    it 'returns false on negative integer input' do
+      expect(helper.is_valid_student_ids([-16, 16])).to be(false)
+    end
+
+    it 'returns false on boolean input' do
+      expect(helper.is_valid_student_ids([16, 0.1])).to be(false)
+    end
+
+    it 'returns false on alphabetical input' do
+      expect(helper.is_valid_student_ids(['abc', 16])).to be(false)
+    end
+  end
+  describe 'is_valid_title' do
+    it 'returns true on valid input' do
+      expect(helper.is_valid_title('hello world')).to be(true)
+    end
+
+    it 'returns false invalid characters' do
+      expect(helper.is_valid_title('**')).to be(false)
+    end
+
+    it 'returns false on too long input' do
+      expect(helper.is_valid_title('A' * 50)).to be(false)
+    end
+  end
+
+  describe 'is_valid_date' do
+    it 'returns true on properly formatted dates' do
+      expect(helper.is_valid_date('2002-03-16T12:00:00Z')).to be(true)
+    end
+
+    it 'returns false on inproperly formatted dates' do
+      expect(helper.is_valid_date('March 16th 2002')).to be(false)
+    end
+
+    it 'returns false on strings with too much text' do
+      expect(helper.is_valid_date('2002-03-16T12:00:00Z*')).to be(false)
+    end
+  end
+end