Test the order of collection items

Gemfile

@@ -3,9 +3,11 @@ source "https://rubygems.org"
 gem "github-pages", group: :jekyll_plugins
 
 group :test do
+  gem "faraday"
   gem "fastimage"
   gem "minitest"
   gem "octokit"
+  gem "pry", require: false
   gem "rake"
   gem "rubocop"
   gem "rubocop-performance"

test/collections_test.rb

@@ -175,6 +175,19 @@ describe "collections" do
         end
       end
     end
+
+    it "has the same order and new items are at the end" do
+      collection_items = items_for_collection(collection)
+      existing_items = existing_items_for_collection(collection)
+
+      collection_items_minus_new_additions = collection_items[0, existing_items.length]
+
+      assert_equal(
+        collection_items_minus_new_additions,
+        existing_items,
+        "expected collection changes to have been appended to the existing item list",
+      )
+    end
   end
 
   def repository_exists?(item)
@@ -184,4 +197,8 @@ describe "collections" do
   def user_exists?(item)
     client.user(item)
   end
+
+  def existing_items_for_collection(collection)
+    existing_collection(collection)["items"]
+  end
 end

test/test_helper.rb

@@ -7,6 +7,7 @@ require "octokit"
 IMAGE_WIDTH = 288
 IMAGE_HEIGHT = 288
 MAX_IMAGE_FILESIZE_IN_BYTES = 75_000
+EXPLORE_FEED_URL = "https://explore-feed.github.com/feed.json"
 
 # See https://github.com/franklsf95/ruby-emoji-regex
 # rubocop:disable Layout/LineLength
@@ -58,6 +59,25 @@ def client
   @client ||= NewOctokit.new(access_token: ENV["GITHUB_TOKEN"])
 end
 
+def existing_explore_feed
+  @_existing_explore_feed ||= begin
+    conn = Faraday.new(EXPLORE_FEED_URL) do |f|
+      f.request :json
+      f.response :json
+    end
+
+    conn.get
+  end
+end
+
+def existing_collection(name)
+  @_existing_collections ||= {}
+
+  @_existing_collections[name] ||= existing_explore_feed.body["collections"].find do |collection|
+    collection["name"] == name
+  end
+end
+
 def valid_uri_scheme?(scheme)
   return false unless scheme