Rails minitest model test with table null:false constraint -

i have started new rails 5 application:

rails new projectone --api --database=postgresql 

created user model:

rails g model user 

with corresponding table migration:

class createusers < activerecord::migration[5.0]   def change     create_table :users |t|       t.string :email,              null: false       t.string :password_digest,    null: false       t.string   :confirmation_token       t.datetime :confirmed_at       t.datetime :confirmation_sent_at       t.timestamps     end   end end 

when run following minitest test:

require 'test_helper'  class usertest < activesupport::testcase   test "the truth"     assert true   end end 

the output is:

error: usertest#test_the_truth: activerecord::statementinvalid: pg::notnullviolation: error:  null value in column "email" violates not-null constraint detail:  failing row contains (980190962, null, null, null, null, null, 2017-09-10 18:58:52.08302, 2017-09-10 18:58:52.08302). : insert "users" ("created_at", "updated_at", "id") values ('2017-09-10 18:58:52.083020', '2017-09-10 18:58:52.083020', 980190962) 

in console, can create empty user object , expected receive above error, not understand trying create object within test. i'd appreciate explanation , advice of how test pass.

the command bundle exec rails g model somemodel invoking bunch of generators include test generator. test generators generate test template , fixtures:

fixtures fancy word sample data. fixtures allow populate testing database predefined data before tests run. fixtures database independent , written in yaml. there 1 file per model.

the minitest trying load environment , populate test database fixtures, fails in case. look's have invalid fixtures. in order resolve issue check forlder test/fixtures , fix or delete fixtures.

read more testing in rails.