[rubygems/rubygems] Add gem build test to check for removed methods.

https://github.com/rubygems/rubygems/commit/c07b9cf4f1

lib/rubygems/test_case.rb

@@ -110,6 +110,8 @@ class Gem::TestCase < Minitest::Test
 
   TEST_PATH = ENV.fetch('RUBYGEMS_TEST_PATH', File.expand_path('../../../test/rubygems', __FILE__))
 
+  SPECIFICATIONS = File.expand_path(File.join(TEST_PATH, "specifications"), __FILE__)
+
   def assert_activate(expected, *specs)
     specs.each do |spec|
       case spec

test/rubygems/specifications/rubyforge-0.0.1.gemspec

@@ -0,0 +1,14 @@
+# -*- encoding: utf-8 -*-
+
+Gem::Specification.new do |s|
+  s.name              = "rubyforge"
+  s.version           = "0.0.1"
+  s.platform          = "ruby"
+  s.require_paths     = ["lib"]
+  s.summary           = "A very bar gem"
+  s.authors           = ["unknown"]
+  s.license           = 'MIT'
+  s.homepage          = 'http://example.com'
+  s.files             = ['README.md']
+  s.rubyforge_project = 'abc'
+end

test/rubygems/test_gem_commands_build_command.rb

@@ -127,6 +127,23 @@ class TestGemCommandsBuildCommand < Gem::TestCase
     util_test_build_gem @gem
   end
 
+  def test_execute_rubyforge_project_warning
+    rubyforge_gemspec = File.join SPECIFICATIONS, "rubyforge-0.0.1.gemspec"
+
+    @cmd.options[:args] = [rubyforge_gemspec]
+
+    use_ui @ui do
+      Dir.chdir @tempdir do
+        @cmd.execute
+      end
+    end
+
+    error = @ui.error.split("\n")
+    assert_equal "WARNING:  rubyforge_project= is deprecated and ignored. Please remove this from your gemspec to ensure that your gem continues to build in the future.", error.shift
+    assert_equal "WARNING:  See https://guides.rubygems.org/specification-reference/ for help", error.shift
+    assert_equal [], error
+  end
+
   def test_execute_strict_with_warnings
     bad_gem = util_spec 'some_bad_gem' do |s|
       s.files = ['README.md']

test/rubygems/test_gem_stub_specification.rb

@@ -4,7 +4,6 @@ require "rubygems/stub_specification"
 
 class TestStubSpecification < Gem::TestCase
 
-  SPECIFICATIONS = File.expand_path(File.join("..", "specifications"), __FILE__)
   FOO = File.join SPECIFICATIONS, "foo-0.0.1-x86-mswin32.gemspec"
   BAR = File.join SPECIFICATIONS, "bar-0.0.2.gemspec"