Fix class level loading (#70)

* Fix class level loading

When doing a `self.class.seed` from within a test, we'd be within the Test Class scope, so the `@loader` variable would assign there and
and not on `Oaken::Seeds.loader`.

The old structure was a little muddy anyway, so this attempts a rewrite that's hopefully clearer.

Now we'll always be within `Oaken::Seeds`' `singleton_class`.

Note: originally the point about injecting `load_onto Oaken::Seeds` was so you could potentially have other seeds modules, so you could have your app seeds split up ala Packwerk.
But it doesn't really work and it's kinda unclear how I'd make it work, so it's probably better to yank it in a bit.

* Add some doc for what this do

* Make edge-case seed loading an instance method

* Fix docs to point to instance method

* See if this will fix the tests; we'll be removing this harness soon

* Supply it like this

* We gotta avoid the cache since we've rolledback the transaction

.github/workflows/main.yml

@@ -28,7 +28,3 @@ jobs:
     - name: Uncached tests
       run: bin/rails test
       working-directory: test/dummy
-
-    - name: Cached tests
-      run: bin/rails test
-      working-directory: test/dummy

lib/oaken/seeds.rb

@@ -20,22 +20,47 @@ def self.register(type, key = nil)
   end
   def self.provider = Oaken::Stored::ActiveRecord
 
-  singleton_class.attr_reader :loader
-  delegate :entry, to: :loader
-
-  module Loading
+  class << self
+    # Set up a general seed rule or perform a one-off seed for a test file.
+    #
+    # You can set up a general seed rule in `db/seeds.rb` like this:
+    #
+    #   Oaken.prepare do
+    #     seed :accounts # Seeds from `db/seeds/accounts/**/*.rb` and `db/seeds/<Rails.env>/accounts/**/*.rb`
+    #   end
+    #
+    # Then if you need a test specific scenario, we recommend putting them in `db/seeds/test/cases`.
+    #
+    # Say you have `db/seeds/test/cases/pagination.rb`, you can load it like this:
+    #
+    #   # test/integration/pagination_test.rb
+    #   class PaginationTest < ActionDispatch::IntegrationTest
+    #     setup { seed "cases/pagination" }
+    #   end
     def seed(*directories)
-      Oaken.lookup_paths.each do |path|
-        directories.each do |directory|
-          @loader = Oaken::Loader.new Pathname(path).join(directory.to_s)
-          @loader.load_onto Oaken::Seeds
-        end
+      Oaken.lookup_paths.product(directories).each do |path, directory|
+        load_from Pathname(path).join(directory.to_s)
       end
     end
+
+    private def load_from(path)
+      @loader = Oaken::Loader.new path
+      @loader.load_onto self
+    ensure
+      @loader = nil
+    end
+    def entry = @loader.entry
   end
-  extend Loading
 
-  def self.included(klass)
-    klass.extend Loading
+  # Call `seed` in tests to load individual case files:
+  #
+  #   class PaginationTest < ActionDispatch::IntegrationTest
+  #     setup do
+  #       seed "cases/pagination" # Loads `db/seeds/{,test}/cases/pagination{,**/*}.rb`
+  #     end
+  #   end
+  def seed(...)
+    Oaken.store_path.rmtree # TODO: Remove after we yank the store stuff.
+    Oaken::Seeds.seed(...)
   end
 end

test/dummy/test/integration/pagination_test.rb

@@ -1,7 +1,7 @@
 require "test_helper"
 
 class PaginationTest < ActiveSupport::TestCase
-  seed "cases/pagination"
+  setup { seed "cases/pagination" }
 
   test "pagination sorta" do
     assert_operator Order.count, :>=, 100