task.rb

class Task
  attr_reader :id
  attr_accessor :title, :description, :done

  def initialize(attr = {})
    @id = attr[:id]
    @title = attr[:title]
    @done = attr[:done] || false
    @description = attr[:description]
  end

  def self.find(id)
    result = DB.execute("SELECT * FROM tasks WHERE id = ?", id).first
    build_task(result) if result
  end

  def self.all
    tasks = DB.execute("SELECT * FROM tasks")
    tasks.map{ |result| build_task(result) }
  end

  def destroy
    DB.execute("DELETE FROM tasks WHERE id = ?", @id)
  end

  def save
    if @id
      DB.execute("UPDATE tasks SET title = ?, description = ?, done = ? WHERE id = ?",
      @title, @description, @done ? 1 : 0, @id)
    else
      DB.execute("INSERT INTO tasks (title, description, done) VALUES (?,?,?)",
      @title, @description, @done ? 1 : 0)
      @id = DB.last_insert_row_id
    end
  end

  def self.build_task(result)
    Task.new(
      id: result['id'],
      title: result['title'],
      description: result['description'],
      done: result['done'] == 1
    )
  end
end

test.rb

require "sqlite3"
require_relative "task"
DB = SQLite3::Database.new("tasks.db")
DB.results_as_hash = true

# find should return a given post
# expect to put out an instance of task with the following data
# 1|Complete Livecode|Implement CRUD on Task|false
p Task.find(1)

# return array of instances of task
p Task.all

# 1 save a new task to the database
new_task = Task.new(title: 'hello', description: 'more beer please')
new_task.save
# expect the task to have an id
p new_task.id

# 2 use save to update an existing task
to_update = Task.find(new_task.id)
to_update.title = "refill"
to_update.save

# expect the task to have been updated and to see a true below

p Task.find(new_task.id).title == 'refill'

# destroy the task we just created
Task.find(new_task.id).destroy


# expect Task.find(new_task.id) to be nil
p Task.find(new_task.id)