Creating Projects using a database class (no database included)

db.rb

module TM
  class DB
    attr_reader :projects

    def initialize
      @projects = {}
      @project_count = 0
    end

    def create_project(data)
      @project_count += 1
      data[:id] = @project_count
      # I've commented out how I would create the complete and time_create
      #   attributes for tasks
      #
      # data[:complete] = false
      # data[:time_created] = Time.now
      @projects[ data[:id] ] = data
      TM::Project.new(data[:name], data[:id])
      # The line below would be used if we had a complete attribute
      # TM::Project.new(data[:name], data[:id], data[:complete])
    end

    def get_project(id)
      data = @projects[id]
      if !data.nil?
        TM::Project.new(data[:name], data[:id])
      end
    end

    def update_project(id, data)
      old_data = @projects[id]
      old_data.merge!(data)
    end

    def destroy_project(id)
      @projects.delete(id)
    end

    # >>>>>>>>>NOTE<<<<<<<<< This method does not work.
    # I created this as a demo of how this method would work
    def get_completed_tasks(project_id)
      results = []
      @tasks.each do |task|
        if task[:project_id] == project_id && task[:complete]
          results << get_task(task[:id])
        end
      end
      results.sort_by()

    end
  end

  def self.db
    @__db_instance ||= TM::DB.new
  end
end

db_spec.rb

require 'spec_helper.rb'

describe TM::DB do
  describe 'db as a singleton' do
    it "returns a DB object" do
      db = TM.db
      expect(db).to be_a(TM::DB)
    end

    it "returns same db object every time" do
      db = TM.db
      db2 = TM.db
      expect(db).to be(db2)
    end
  end

  describe "projects inside db" do
    it "contains storage for projects" do
      expect(TM.db.projects).to be_a(Hash)
    end

    describe "#create_project" do
      let(:project) {TM.db.create_project(:name => "My Project")}

      it "creates a new project entity" do
        expect(project).to be_a(TM::Project)
        expect(project.id).to be_a(Fixnum)
        expect(project.name).to eq("My Project")
      end

      it "stores information in the db" do
        expect(TM.db.projects[project.id]).to eq({
          :name => "My Project",
          :id => project.id
        })
      end

      it "gives a unique id every time" do
        p1 = TM.db.create_project(:name => "p1")
        p2 = TM.db.create_project(:name => "p1")
        expect(p1.id).to_not eq(p2.id)
      end
    end

    describe "#get_project" do
      it "returns a project entity with the proper data" do
        p1 = TM.db.create_project(:name => "p1")
        p2 = TM.db.create_project(:name => "p1")
        project = TM.db.get_project(p1.id)
        expect(project).to be_a(TM::Project)
        expect(p1.id).to eq(project.id)
        expect(p1.name).to eq(project.name)
      end

      it "returns nil if the project doesn't exist" do
        project = TM.db.get_project(3)
        expect(project).to eq(nil)
      end
    end

    describe "#update_project" do
      it "updates the project in the db" do
        p1 = TM.db.create_project(:name => "p1")
        # t1 = TM.db.create_task(:project_id => 1, :description: "blah", :priority_num => 3)
        TM.db.update_project(p1.id, :name => "Hello")
        project = TM.db.get_project(p1.id)
        expect(project.name).to eq("Hello")
        expect(project.id).to eq(p1.id)
      end
    end

    describe "#destroy_project" do
      it "destroys project from db" do
        p1 = TM.db.create_project(:name => "p1")
        TM.db.destroy_project(p1.id)
        project = TM.db.get_project(p1.id)
        expect(project).to eq(nil)
      end
    end

  end
end