ActiveSupport's Date#all_* ranges inadvertently exclude times that should match.

all_year.rb

# frozen_string_literal: true

require "bundler/inline"
gemfile(true) do
  source "https://rubygems.org"
  gem "rails", github: "rails/rails"
  gem "sqlite3"
end

require "active_record"
require "logger"
require "minitest/autorun"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :users, force: true do |t|
    t.string :name
    t.datetime :born_at
  end
end

class User < ActiveRecord::Base
  scope :same_birth_year, ->(date) { where born_at: date.all_year }

  def same_birth_year?(date)
    date.all_year.cover?(born_at)
  end
end

class RangeTest < Minitest::Test
  def setup
    User.delete_all

    @users = User.create! [
      { name: "User1", born_at: '2019-12-25 16:32 UTC' },
      { name: "User2", born_at: '2019-12-31 23:01 UTC' },
      { name: "User3", born_at: '2020-01-01 00:00 UTC' }
    ]

    @dob = Date.parse('2019-06-01')
  end

  def test_same_birth_year_count
    assert_equal 2, User.same_birth_year(@dob).count
  end

  def test_birth_year_coverage
    assert_equal [true, true, false], @users.map { |user| user.same_birth_year?(@dob) }
  end
end