Add user model and unit tests

app/models/user.rb

@@ -0,0 +1,8 @@
+class User < ApplicationRecord
+  validates :email, uniqueness: true, presence: true, :on => :create
+  validates :username, uniqueness: true, presence: true, :on => :create
+  validates :email, format:{ with: /\S+@\S+[.]\S+/, message: "Must be a valid email format." }
+  validates :password_digest, presence: true
+
+  has_secure_password
+end

config/routes.rb

@@ -1,3 +1,7 @@
 Rails.application.routes.draw do
-  # For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html
+  namespace :api, defaults: { format: :json }  do
+    namespace :v1 do
+      resources :users
+    end
+  end
 end

db/migrate/20210413093535_create_users.rb

@@ -0,0 +1,13 @@
+class CreateUsers < ActiveRecord::Migration[6.1]
+  def change
+    create_table :users do |t|
+      t.string :email, null: false
+      t.index :email, unique: true
+      t.string :username, null: false
+      t.index :username, unique: true
+      t.string :password_digest
+
+      t.timestamps
+    end
+  end
+end

db/schema.rb

@@ -0,0 +1,25 @@
+# This file is auto-generated from the current state of the database. Instead
+# of editing this file, please use the migrations feature of Active Record to
+# incrementally modify your database, and then regenerate this schema definition.
+#
+# This file is the source Rails uses to define your schema when running `bin/rails
+# db:schema:load`. When creating a new database, `bin/rails db:schema:load` tends to
+# be faster and is potentially less error prone than running all of your
+# migrations from scratch. Old migrations may fail to apply correctly if those
+# migrations use external dependencies or application code.
+#
+# It's strongly recommended that you check this file into your version control system.
+
+ActiveRecord::Schema.define(version: 2021_04_13_093535) do
+
+  create_table "users", force: :cascade do |t|
+    t.string "email", null: false
+    t.string "username", null: false
+    t.string "password_digest"
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+    t.index ["email"], name: "index_users_on_email", unique: true
+    t.index ["username"], name: "index_users_on_username", unique: true
+  end
+
+end

test/fixtures/users.yml

@@ -0,0 +1,6 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+one:
+  email: one@one.com
+  username: OneUsername
+  password_digest: v@lid_pa$$w0rd

test/models/user_test.rb

@@ -0,0 +1,25 @@
+require "test_helper"
+
+class UserTest < ActiveSupport::TestCase
+  test 'user with a valid email should be valid' do
+  user = User.new(email: "test@test.com", username: "UserTest", password_digest: 'password')
+  assert user.valid?
+  end
+
+  test 'user with taken username should be invalid' do
+  other_user = users(:one)
+  user = User.new(email: "test@email.com", username: other_user.username, password_digest: "test_password")
+  assert_not user.valid?
+  end
+
+  test 'user with invalid email should be invalid' do
+  user = User.new(email: "test_invalid_email", username: "UserTest", password_digest: "test_password")
+  assert_not user.valid?
+  end
+
+  test 'user with taken email should be invalid' do
+  other_user = users(:one)
+  user = User.new(email: other_user.email, username: "UserTest", password_digest: "test_password")
+  assert_not user.valid?
+  end
+end