Run ruby test in heroku application without database

Question

I have one rails API application (App1), which doesn't have any database (no schema.rb file), but i am using some other application's database without adding any heroku postgres addon so when i push this application to heroku, i set the environment variable as DATABASE_URL = [ Database url of App2 ], also i have added some test cases with mini-test and enabled CI in heroku, it will run the test before the deployment but that time i am getting this error

and this is my application.rb

    require_relative 'boot'

    require "rails"
    # Pick the frameworks you want:
    require "active_model/railtie"
    require "active_job/railtie"
    require "active_record/railtie"
    require "action_controller/railtie"
    require "action_mailer/railtie"
    require "action_view/railtie"
    require "action_cable/engine"
    # require "sprockets/railtie"
    require "rails/test_unit/railtie"

    # Require the gems listed in Gemfile, including any gems
    # you've limited to :test, :development, or :production.
    Bundler.require(*Rails.groups)

    module DemoGroup
      class Application < Rails::Application
        # Initialize configuration defaults for originally generated Rails version.
        config.load_defaults 5.1

        # Settings in config/environments/* take precedence over those specified here.
        # Application configuration should go into files in config/initializers
        # -- all .rb files in that directory are automatically loaded.

        # Only loads a smaller set of middleware suitable for API only apps.
        # Middleware like session, flash, cookies can be added back manually.
        # Skip views, helpers and assets when generating a new resource.
        config.api_only = true
      end
    end

is there any way i can run this test in heroku

Answer 1

The correct way to do this is by attaching the Postgres addon from app2 to app1.

Lets say you set DATABASE_URL on app1 to point to the attachment on app2. Heroku then needs to do maintenance - which changes the database url as its shifted to another server. Heroku is nice enough to automatically update DATABASE_URL on app2 - but app1 will be pointing to an invalid url.

This assumes you have the Heroku CLI client installed.

First get a list of the attachments:

$ heroku addons

Remove the default Postgres addon

$ heroku addons:remove heroku-postgresql:dev --app app1

Replace app2 with the name of your application on heroku.

Attach the addon from the other application.

Then attach the Postgres add-on from app2 to app1:

$ heroku addons:attach attachment_name -a app1

Schema.rb

schema.rb is required for ActiveRecord to work properly. If app1 does actually create migrations you can just commit an "empty" schema.rb:

ActiveRecord::Schema.define(version: 0) do
  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"
end