[rubygems/rubygems] Refactor spec helpers for reading lockfiles

https://github.com/rubygems/rubygems/commit/ea2a30ba08

spec/bundler/commands/lock_spec.rb

@@ -1,10 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe "bundle lock" do
-  def read_lockfile(file = "Gemfile.lock")
-    bundled_app(file).read
-  end
-
   let(:repo) { gem_repo1 }
 
   before :each do

spec/bundler/support/helpers.rb

@@ -244,7 +244,7 @@ module Spec
       contents = args.pop
 
       if contents.nil?
-        File.open(bundled_app_gemfile, "r", &:read)
+        read_gemfile
       else
         create_file(args.pop || "Gemfile", contents)
       end
@@ -254,12 +254,24 @@ module Spec
       contents = args.pop
 
       if contents.nil?
-        File.open(bundled_app_lock, "r", &:read)
+        read_lockfile
       else
         create_file(args.pop || "Gemfile.lock", contents)
       end
     end
 
+    def read_gemfile(file = "Gemfile")
+      read_bundled_app_file(file)
+    end
+
+    def read_lockfile(file = "Gemfile.lock")
+      read_bundled_app_file(file)
+    end
+
+    def read_bundled_app_file(file)
+      bundled_app(file).read
+    end
+
     def strip_whitespace(str)
       # Trim the leading spaces
       spaces = str[/\A\s+/, 0] || ""