1 files changed, 51 insertions, 11 deletions
diff --git a/test/mkmf/test_config.rb b/test/mkmf/test_config.rb
index 07ed641415..0d2cb3751c 100644
--- a/test/mkmf/test_config.rb
+++ b/test/mkmf/test_config.rb
@@ -1,17 +1,57 @@
 # frozen_string_literal: false
-$extmk = true
+require_relative 'base'
+require 'tempfile'
 
-require 'test/unit'
-require 'mkmf'
+class TestMkmfConfig < TestMkmf
+  def test_dir_config
+    bug8074 = '[Bug #8074]'
+    lib = RbConfig.expand(RbConfig::MAKEFILE_CONFIG["libdir"], "exec_prefix"=>"/test/foo")
+    assert_separately([], %w[--with-foo-dir=/test/foo], <<-"end;")
+      assert_equal(%w[/test/foo/include #{lib}], dir_config("foo"), #{bug8074.dump})
+    end;
+  end
+
+  def test_with_config_with_arg_and_value
+    assert_separately([], %w[--with-foo=bar], <<-'end;')
+      assert_equal("bar", with_config("foo"))
+    end;
+  end
+
+  def test_with_config_with_arg_and_no_value
+    assert_separately([], %w[--with-foo], <<-'end;')
+      assert_equal(true, with_config("foo"))
+    end;
+  end
+
+  def test_with_config_without_arg
+    assert_separately([], %w[--without-foo], <<-'end;')
+      assert_equal(false, with_config("foo"))
+    end;
+  end
+
+  def test_with_target_rbconfig
+    Tempfile.create(%w"rbconfig .rb", ".") do |tmp|
+      tmp.puts <<~'end;'
+      module RbConfig
+        CONFIG = {}
+        MAKEFILE_CONFIG = {}
 
-class TestMkmf < Test::Unit::TestCase
-  class TestConfig < Test::Unit::TestCase
-    def test_dir_config
-      bug8074 = '[Bug #8074]'
-      lib = RbConfig.expand(RbConfig::MAKEFILE_CONFIG["libdir"], "exec_prefix"=>"")
-      assert_separately %w[-rmkmf - -- --with-foo-dir=/test/foo], %{
-        assert_equal(%w[/test/foo/include /test/foo#{lib}], dir_config("foo"), #{bug8074.dump})
-      }
+        def self.fire_update!(key, value); end
+        def self.expand(val, config = CONFIG); val; end
+      end;
+      ::RbConfig::CONFIG.each do |k, v|
+        tmp.puts "  CONFIG[#{k.dump}] = #{v.dump}"
+      end
+      ::RbConfig::MAKEFILE_CONFIG.each do |k, v|
+        tmp.puts "  MAKEFILE_CONFIG[#{k.dump}] = #{v.dump}"
+      end
+      tmp.puts "  CONFIG['testing-only'] = 'ok'"
+      tmp.puts "end"
+      tmp.close
+      assert_separately([], ["--target-rbconfig=#{tmp.path}"], <<-'end;')
+        assert_equal("ok", MakeMakefile::RbConfig::CONFIG["testing-only"])
+        assert_not_equal(::RbConfig, MakeMakefile::RbConfig)
+      end;
     end
   end
 end