Get tests working for FileFetcher

docker/.gitignore

@@ -0,0 +1,5 @@
+/.bundle/
+/.env
+/tmp
+/dependabot-*.gem
+Gemfile.lock

docker/lib/dependabot/docker/file_fetcher.rb

@@ -1,40 +1,42 @@
 # frozen_string_literal: true
 
+require "dependabot/file_fetchers"
 require "dependabot/file_fetchers/base"
 
 module Dependabot
-  module FileFetchers
-    module Docker
-      class Docker < Dependabot::FileFetchers::Base
-        def self.required_files_in?(filenames)
-          filenames.any? { |f| f.match?(/dockerfile/i) }
-        end
-
-        def self.required_files_message
-          "Repo must contain a Dockerfile."
-        end
-
-        private
-
-        def fetch_files
-          fetched_files = []
-          fetched_files += dockerfiles
-
-          return fetched_files if fetched_files.any?
-
-          raise(
-            Dependabot::DependencyFileNotFound,
-            File.join(directory, "Dockerfile")
-          )
-        end
-
-        def dockerfiles
-          @dockerfiles ||=
-            repo_contents(raise_errors: false).
-            select { |f| f.type == "file" && f.name.match?(/dockerfile/i) }.
-            map { |f| fetch_file_from_host(f.name) }
-        end
+  module Docker
+    class FileFetcher < Dependabot::FileFetchers::Base
+      def self.required_files_in?(filenames)
+        filenames.any? { |f| f.match?(/dockerfile/i) }
+      end
+
+      def self.required_files_message
+        "Repo must contain a Dockerfile."
+      end
+
+      private
+
+      def fetch_files
+        fetched_files = []
+        fetched_files += dockerfiles
+
+        return fetched_files if fetched_files.any?
+
+        raise(
+          Dependabot::DependencyFileNotFound,
+          File.join(directory, "Dockerfile")
+        )
+      end
+
+      def dockerfiles
+        @dockerfiles ||=
+          repo_contents(raise_errors: false).
+          select { |f| f.type == "file" && f.name.match?(/dockerfile/i) }.
+          map { |f| fetch_file_from_host(f.name) }
       end
     end
   end
 end
+
+Dependabot::FileFetchers.
+  register("docker", Dependabot::Docker::FileFetcher)

docker/spec/dependabot/docker/file_fetcher_spec.rb

@@ -1,9 +1,10 @@
 # frozen_string_literal: true
 
-require "dependabot/file_fetchers/docker/docker"
-require_relative "../shared_examples_for_file_fetchers"
+require "spec_helper"
+require "dependabot/docker/file_fetcher"
+require_common_spec "file_fetchers/shared_examples_for_file_fetchers"
 
-RSpec.describe Dependabot::FileFetchers::Docker::Docker do
+RSpec.describe Dependabot::Docker::FileFetcher do
   it_behaves_like "a dependency file fetcher"
 
   let(:source) do

docker/spec/fixtures/github/not_found.json

@@ -0,0 +1,4 @@
+{
+    "message": "Not Found",
+    "documentation_url": "https://developer.github.com/v3"
+}

lib/dependabot/file_fetchers.rb

@@ -7,7 +7,6 @@
 require "dependabot/file_fetchers/java/gradle"
 require "dependabot/file_fetchers/php/composer"
 require "dependabot/file_fetchers/git/submodules"
-require "dependabot/file_fetchers/docker/docker"
 require "dependabot/file_fetchers/elixir/hex"
 require "dependabot/file_fetchers/rust/cargo"
 require "dependabot/file_fetchers/dotnet/nuget"
@@ -25,7 +24,6 @@ module FileFetchers
       "pip" => FileFetchers::Python::Pip,
       "composer" => FileFetchers::Php::Composer,
       "submodules" => FileFetchers::Git::Submodules,
-      "docker" => FileFetchers::Docker::Docker,
       "hex" => FileFetchers::Elixir::Hex,
       "cargo" => FileFetchers::Rust::Cargo,
       "nuget" => FileFetchers::Dotnet::Nuget,