Email has already been takenと出てテストがパスしない

Question

お世話になっております。validationについての質問です。

前提・実現したいこと

railsのバリデーションでemailの大文字小文字の区別をするためにcase_sensitive:trueにしたい。

発生している問題・エラーメッセージ

Userモデルに明示的にcase_sensitive: trueと書いたにも関わらず、テストがパスしない。

User
DEPRECATION WARNING: Uniqueness validator will no longer enforce case sensitive comparison in Rails 6.1. To continue case sensitive comparison on the :email attribute in User model, pass `case_sensitive: true` option explicitly to the uniqueness validator. (called from block (2 levels) in <main> at /usr/src/app/spec/models/user_spec.rb:6)
  is valid with name, email and password
  emailの小文字と大文字を識別できるか
DEPRECATION WARNING: Uniqueness validator will no longer enforce case sensitive comparison in Rails 6.1. To continue case sensitive comparison on the :email attribute in User model, pass `case_sensitive: true` option explicitly to the uniqueness validator. (called from block (3 levels) in <main> at /usr/src/app/spec/models/user_spec.rb:11)
DEPRECATION WARNING: Uniqueness validator will no longer enforce case sensitive comparison in Rails 6.1. To continue case sensitive comparison on the :email attribute in User model, pass `case_sensitive: true` option explicitly to the uniqueness validator. (called from block (3 levels) in <main> at /usr/src/app/spec/models/user_spec.rb:13)
    全く同じemailアドレスの時
DEPRECATION WARNING: Uniqueness validator will no longer enforce case sensitive comparison in Rails 6.1. To continue case sensitive comparison on the :email attribute in User model, pass `case_sensitive: true` option explicitly to the uniqueness validator. (called from block (3 levels) in <main> at /usr/src/app/spec/models/user_spec.rb:17)
DEPRECATION WARNING: Uniqueness validator will no longer enforce case sensitive comparison in Rails 6.1. To continue case sensitive comparison on the :email attribute in User model, pass `case_sensitive: true` option explicitly to the uniqueness validator. (called from block (3 levels) in <main> at /usr/src/app/spec/models/user_spec.rb:19)
    大文字小文字の区別がある時 (FAILED - 1)

Failures:

  1) User emailの小文字と大文字を識別できるか 大文字小文字の区別がある時
     Failure/Error: expect(user3).to be_valid
       expected #<User id: nil, provider: "email", uid: "", name: "test2", image: nil, email: "[e-mail]", allow_password_change: false, created_at: nil, updated_at: nil> to be valid, but got errors: Email has already been taken, Email has already been taken
     # ./spec/models/user_spec.rb:19:in `block (3 levels) in <main>'
     # /usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:55:in `load'
     # /usr/local/bundle/gems/bootsnap-1.4.6/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:55:in `load'
     # /usr/local/bundle/gems/spring-commands-rspec-1.0.4/lib/spring/commands/rspec.rb:18:in `call'
     # -e:1:in `<main>'

Finished in 0.28343 seconds (files took 0.29851 seconds to load)
3 examples, 1 failure

Failed examples:

rspec ./spec/models/user_spec.rb:16 # User emailの小文字と大文字を識別できるか 大文字小文字の区別がある時

該当のソースコード

#####user_spec.rb

require "rails_helper"

RSpec.describe User, type: :model do
  it "is valid with name, email and password" do
    user = FactoryBot.build(:user)
    expect(user).to be_valid
  end

  context "emailの小文字と大文字を識別できるか" do
    it "全く同じemailアドレスの時" do
      user = FactoryBot.create(:user)
      user2 = FactoryBot.build(:user, name: "test2")
      expect(user2).not_to be_valid
    end

    it "大文字小文字の区別がある時" do
      user = FactoryBot.create(:user)
      user2 = FactoryBot.build(:user, name: "test2", email: "[e-mail]")
      expect(user2).to be_valid
    end
  end
end

#####user.rb

# frozen_string_literal: true

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable and :omniauthable

  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable
  include DeviseTokenAuth::Concerns::User
  validates :email, uniqueness: { case_sensitive: true }
end

#####spec_helper.rb

require 'database_cleaner'

RSpec.configure do |config|

  # databaseを空にする
  config.before(:suite) do
    DatabaseCleaner.strategy = :truncation
  end
  config.before(:each) do
    DatabaseCleaner.start
  end
  config.after(:each) do
    DatabaseCleaner.clean
  end

  config.expect_with :rspec do |expectations|
    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
  end

  config.mock_with :rspec do |mocks|
    mocks.verify_partial_doubles = true
  end

  config.shared_context_metadata_behavior = :apply_to_host_groups
end

#####spec/factories/users.rb

FactoryBot.define do
  factory :user do
    name                  {"test"}
    email                 {"[e-mail]"}
    password              {"password"}
    password_confirmation {"password"}
  end
end

試したこと

明示的にcase_sensitive: falseにしてみましたが、rspecの結果が全く同じです。

補足情報（FW/ツールのバージョンなど）

devise 4.7.1
devise_token_auth 1.1.3
factory_bot_rails 5.1.1
ruby 2.6.3
rails 6.0.2.2
rspec-rails 4.0.0

Answer 1

エラーの"Email has already been taken"から、

「DBがロールバックされずにデータが残っているのではないか」

との指摘を受け、下記の記事を参考にテスト環境のDBを初期化するとうまくいきました。
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