Generate a spec file when a data_migration is generated

[bgwilson87]

Hi there, I'm migrating from an old gem called datafix https://github.com/dimroc/datafix

It has a nice feature where it generates a spec file for you when you generate a data migration. With complicated data migrations, I find it's best to write some tests to make sure the data migration is doing what I expect. Do you think this is something you could support?

For example
rails g data_migration add_this_to_that

would generate a spec file in addition to the migration file at this location
spec/db/data/20200701180749_add_this_to_that_spec.rb

with this content:

require "rails_helper"
require Rails.root.join("db", "data", "20200701180749_add_this_to_that")

describe AddThisToThat do
  describe ".up" do
    pending "Needs tests"
  end

  describe ".down" do
    pending "Needs tests"
  end
end

[schwern]

I want this as well and might put a little work into it. My template goes a little further adding the special sauce necessary to keep the test quiet, and handy subject lines.

require "rails_helper"
require Rails.root.join("db", "data", "20200701180749_add_this_to_that")

describe AddThisToThat do
  let(:migrator) {
    described_class.new.tap do |m|
      m.verbose = false
    end
  }

  describe "#up" do
    subject { migrator.migrate(:up) }

    pending "Needs tests"
  end

  describe "#down" do
    subject { migrator.migrate(:down) }

    pending "Needs tests"
  end
end

What do you think?

[ilyakatz]

i knows it's not entirely the same, but can this use case can be solved with #232