Much work.

test/models/user_test.rb

@@ -0,0 +1,8 @@
+require "test_helper"
+
+class UserTest < ActiveSupport::TestCase
+  test "downcases and strips email_address" do
+    user = User.new(email_address: " DOWNCASED@EXAMPLE.COM ")
+    assert_equal("downcased@example.com", user.email_address)
+  end
+end