[bundler/bundler] Extract a with_root_gemspec helper

https://github.com/bundler/bundler/commit/f20c2bdf6a

spec/bundler/quality_spec.rb

@@ -225,13 +225,7 @@ RSpec.describe "The library itself" do
   end
 
   it "can still be built" do
-    if ruby_core?
+    with_root_gemspec do |gemspec|
-      spec = Gem::Specification.load(gemspec.to_s)
-      spec.bindir = "libexec"
-      File.open(root.join("bundler.gemspec").to_s, "w") {|f| f.write spec.to_ruby }
-      Dir.chdir(root) { gem_command! :build, root.join("bundler.gemspec") }
-      FileUtils.rm(root.join("bundler.gemspec"))
-    else
       Dir.chdir(root) { gem_command! :build, gemspec }
     end
 

spec/bundler/support/helpers.rb

@@ -298,13 +298,7 @@ module Spec
       gem_repo = options.fetch(:gem_repo) { gem_repo1 }
       gems.each do |g|
         path = if g == :bundler
-          if ruby_core?
+          with_root_gemspec do |gemspec|
-            spec = Gem::Specification.load(gemspec.to_s)
-            spec.bindir = "libexec"
-            File.open(root.join("bundler.gemspec").to_s, "w") {|f| f.write spec.to_ruby }
-            Dir.chdir(root) { gem_command! :build, root.join("bundler.gemspec") }
-            FileUtils.rm(root.join("bundler.gemspec"))
-          else
             Dir.chdir(root) { gem_command! :build, gemspec }
           end
           bundler_path = root.join("bundler-#{Bundler::VERSION}.gem")

spec/bundler/support/path.rb

@@ -132,6 +132,18 @@ module Spec
       tmp "tmpdir", *args
     end
 
+    def with_root_gemspec
+      if ruby_core?
+        spec = Gem::Specification.load(gemspec.to_s)
+        spec.bindir = "libexec"
+        File.open(root.join("bundler.gemspec").to_s, "w") {|f| f.write spec.to_ruby }
+        yield(root.join("bundler.gemspec"))
+        FileUtils.rm(root.join("bundler.gemspec"))
+      else
+        yield(gemspec)
+      end
+    end
+
     def ruby_core?
       # avoid to wornings
       @ruby_core ||= nil