diff --git a/ext/win32/lib/win32/registry.rb b/ext/win32/lib/win32/registry.rb
index c801b1327b..e84653d945 100644
--- a/ext/win32/lib/win32/registry.rb
+++ b/ext/win32/lib/win32/registry.rb
@@ -69,11 +69,7 @@ For detail, see the MSDN[http://msdn.microsoft.com/library/en-us/sysinfo/base/pr
   WCHAR_NUL = "\0".encode(WCHAR).freeze
   WCHAR_CR = "\r".encode(WCHAR).freeze
   WCHAR_SIZE = WCHAR_NUL.bytesize
-  begin
-    LOCALE = Encoding.find(Encoding.locale_charmap)
-  rescue ArgumentError
-    LOCALE = Encoding::UTF_8
-  end
+  LOCALE = Encoding::UTF_8
 
   class Registry
 
@@ -567,9 +563,16 @@ For detail, see the MSDN[http://msdn.microsoft.com/library/en-us/sysinfo/base/pr
     end
 
     #
-    # Enumerate values.
+    # Enumerate all values in this registry path.
+    #
+    # For each value it yields key, type and data.
+    #
+    # key is a String which contains name of key.
+    # type is a type contant kind of Win32::Registry::REG_*
+    # data is the value of this key.
     #
     def each_value
+      return enum_for(:each_value) unless block_given?
       index = 0
       while true
         begin
@@ -600,13 +603,16 @@ For detail, see the MSDN[http://msdn.microsoft.com/library/en-us/sysinfo/base/pr
     end
 
     #
-    # Enumerate subkeys.
+    # Enumerate all subkeys.
+    #
+    # For each subkey it yields subkey and wtime.
     #
     # subkey is String which contains name of subkey.
     # wtime is last write time as FILETIME (64-bit integer).
     # (see Registry.wtime2time)
     #
     def each_key
+      return enum_for(:each_key) unless block_given?
       index = 0
       while true
         begin
diff --git a/ext/win32/win32-registry.gemspec b/ext/win32/win32-registry.gemspec
new file mode 100644
index 0000000000..b6df247574
--- /dev/null
+++ b/ext/win32/win32-registry.gemspec
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+Gem::Specification.new do |spec|
+  spec.name = "win32-registry"
+  spec.version = "0.0.1"
+  spec.authors = ["U.Nakamura"]
+  spec.email = ["usa@garbagecollect.jp"]
+
+  spec.summary = %q{Provides an interface to the Windows Registry in Ruby}
+  spec.description = spec.summary
+  spec.homepage = "https://github.com/ruby/win32-registry"
+  spec.required_ruby_version = ">= 2.6.0"
+
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = spec.homepage
+
+  # Specify which files should be added to the gem when it is released.
+  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  spec.files = Dir.chdir(__dir__) do
+    `git ls-files -z`.split("\x0").reject do |f|
+      (File.expand_path(f) == __FILE__) ||
+        f.start_with?(*%w[bin/ test/ spec/ features/ .git .github appveyor Gemfile])
+    end
+  end
+  spec.bindir = "exe"
+  spec.executables = spec.files.grep(%r{\Aexe/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+
+  spec.add_dependency "fiddle", "~> 1.0"
+end
diff --git a/test/win32/test_registry.rb b/test/win32/test_registry.rb
index 02cafc09b0..8a98405a79 100644
--- a/test/win32/test_registry.rb
+++ b/test/win32/test_registry.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 if /mswin|mingw|cygwin/ =~ RUBY_PLATFORM
   begin
     require 'win32/registry'
@@ -10,7 +12,19 @@ end
 if defined?(Win32::Registry)
   class TestWin32Registry < Test::Unit::TestCase
     COMPUTERNAME = 'SYSTEM\\CurrentControlSet\\Control\\ComputerName\\ComputerName'
-    VOLATILE_ENVIRONMENT = 'Volatile Environment'
+
+    private def backslachs(path)
+      path.gsub("/", "\\")
+    end
+
+    TEST_REGISTRY_KEY = "SOFTWARE/ruby-win32-registry-test/"
+
+    def setup
+      Win32::Registry::HKEY_CURRENT_USER.open(backslachs(File.dirname(TEST_REGISTRY_KEY))) do |reg|
+        reg.delete_key File.basename(TEST_REGISTRY_KEY), true
+      end
+    rescue Win32::Registry::Error
+    end
 
     def test_predefined
       assert_predefined_key Win32::Registry::HKEY_CLASSES_ROOT
@@ -24,6 +38,38 @@ if defined?(Win32::Registry)
       assert_predefined_key Win32::Registry::HKEY_DYN_DATA
     end
 
+    def test_open_no_block
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)).close
+
+      reg = Win32::Registry::HKEY_CURRENT_USER.open(backslachs(TEST_REGISTRY_KEY), Win32::Registry::KEY_ALL_ACCESS)
+      assert_kind_of Win32::Registry, reg
+      assert_equal true, reg.open?
+      assert_equal false, reg.created?
+      reg["test"] = "abc"
+      reg.close
+      assert_raise(Win32::Registry::Error) do
+        reg["test"] = "abc"
+      end
+    end
+
+    def test_open_with_block
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)).close
+
+      regs = []
+      Win32::Registry::HKEY_CURRENT_USER.open(backslachs(TEST_REGISTRY_KEY), Win32::Registry::KEY_ALL_ACCESS) do |reg|
+        regs << reg
+        assert_equal true, reg.open?
+        assert_equal false, reg.created?
+        reg["test"] = "abc"
+      end
+
+      assert_equal 1, regs.size
+      assert_kind_of Win32::Registry, regs[0]
+      assert_raise(Win32::Registry::Error) do
+        regs[0]["test"] = "abc"
+      end
+    end
+
     def test_class_open
       name1, keys1 = Win32::Registry.open(Win32::Registry::HKEY_LOCAL_MACHINE, "SYSTEM") do |reg|
         assert_predicate reg, :open?
@@ -46,32 +92,145 @@ if defined?(Win32::Registry)
       end
     end
 
-    def test_create
+    def test_create_volatile
       desired = Win32::Registry::KEY_ALL_ACCESS
       option = Win32::Registry::REG_OPTION_VOLATILE
-      Win32::Registry::HKEY_CURRENT_USER.open(VOLATILE_ENVIRONMENT, desired) do |reg|
-        v = self.class.unused_value(reg)
-        begin
-          reg.create(v, desired, option) {}
-        ensure
-          reg.delete_key(v, true)
-        end
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY), desired) do |reg|
+        reg.create("volkey", desired, option) {}
+        reg.delete_key("volkey", true)
+      end
+    end
+
+    def test_create_no_block
+      reg = Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY))
+      assert_kind_of Win32::Registry, reg
+      assert_equal true, reg.open?
+      assert_equal true, reg.created?
+      reg["test"] = "abc"
+      reg.close
+      assert_equal false, reg.open?
+      assert_raise(Win32::Registry::Error) do
+        reg["test"] = "abc"
+      end
+    end
+
+    def test_create_with_block
+      regs = []
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        regs << reg
+        reg["test"] = "abc"
+        assert_equal true, reg.open?
+        assert_equal true, reg.created?
+      end
+
+      assert_equal 1, regs.size
+      assert_kind_of Win32::Registry, regs[0]
+      assert_equal false, regs[0].open?
+      assert_raise(Win32::Registry::Error) do
+        regs[0]["test"] = "abc"
       end
     end
 
     def test_write
       desired = Win32::Registry::KEY_ALL_ACCESS
-      Win32::Registry::HKEY_CURRENT_USER.open(VOLATILE_ENVIRONMENT, desired) do |reg|
-        v = self.class.unused_value(reg)
-        begin
-          reg.write_s(v, "data")
-          assert_equal [Win32::Registry::REG_SZ, "data"], reg.read(v)
-          reg.write_i(v, 0x5fe79027)
-          assert_equal [Win32::Registry::REG_DWORD, 0x5fe79027], reg.read(v)
-        ensure
-          reg.delete(v)
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY), desired) do |reg|
+        reg.write_s("key1", "data")
+        assert_equal [Win32::Registry::REG_SZ, "data"], reg.read("key1")
+        reg.write_i("key2", 0x5fe79027)
+        assert_equal [Win32::Registry::REG_DWORD, 0x5fe79027], reg.read("key2")
+      end
+    end
+
+    def test_accessors
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        assert_kind_of Integer, reg.hkey
+        assert_kind_of Win32::Registry, reg.parent
+        assert_equal "HKEY_CURRENT_USER", reg.parent.name
+        assert_equal "SOFTWARE\\ruby-win32-registry-test\\", reg.keyname
+        assert_equal Win32::Registry::REG_CREATED_NEW_KEY, reg.disposition
+      end
+    end
+
+    def test_name
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        assert_equal "HKEY_CURRENT_USER\\SOFTWARE\\ruby-win32-registry-test\\", reg.name
+      end
+    end
+
+    def test_keys
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        reg.create("key1")
+        assert_equal ["key1"], reg.keys
+      end
+    end
+
+    def test_each_key
+      keys = []
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        reg.create("key1")
+        reg.each_key { |*a| keys << a }
+      end
+      assert_equal [2], keys.map(&:size)
+      assert_equal ["key1"], keys.map(&:first)
+      assert_in_delta Win32::Registry.time2wtime(Time.now), keys[0][1], 10_000_000_000, "wtime should roughly match Time.now"
+    end
+
+    def test_each_key_enum
+      keys = nil
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        reg.create("key1")
+        reg.create("key2")
+        reg.create("key3")
+        reg["value1"] = "abcd"
+        keys = reg.each_key.to_a
+      end
+      assert_equal 3, keys.size
+      assert_equal [2, 2, 2], keys.map(&:size)
+      assert_equal ["key1", "key2", "key3"], keys.map(&:first)
+    end
+
+    def test_values
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        reg.create("key1")
+        reg["value1"] = "abcd"
+        assert_equal ["abcd"], reg.values
+      end
+    end
+
+    def test_each_value
+      vals = []
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        reg.create("key1")
+        reg["value1"] = "abcd"
+        reg.each_value { |*a| vals << a }
+      end
+      assert_equal [["value1", Win32::Registry::REG_SZ, "abcd"]], vals
+    end
+
+    def test_each_value_enum
+      vals = nil
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        reg.create("key1")
+        reg["value1"] = "abcd"
+        reg["value2"] = 42
+        vals = reg.each_value.to_a
+      end
+      assert_equal [["value1", Win32::Registry::REG_SZ, "abcd"],
+                    ["value2", Win32::Registry::REG_DWORD, 42]], vals
+    end
+
+    def test_utf8_encoding
+      keys = []
+      Win32::Registry::HKEY_CURRENT_USER.create(backslachs(TEST_REGISTRY_KEY)) do |reg|
+        reg.create("abc EUR")
+        reg.create("abc €")
+        reg.each_key do |subkey|
+          keys << subkey
         end
       end
+
+      assert_equal [Encoding::UTF_8] * 2, keys.map(&:encoding)
+      assert_equal ["abc EUR", "abc €"], keys
     end
 
     private
@@ -79,19 +238,7 @@ if defined?(Win32::Registry)
     def assert_predefined_key(key)
       assert_kind_of Win32::Registry, key
       assert_predicate key, :open?
-      assert_not_predicate key, :created?
-    end
-
-    class << self
-      def unused_value(reg, prefix = "Test_", limit = 100, fail: true)
-        limit.times do
-          v =  + rand(0x100000).to_s(36)
-          reg.read(v)
-        rescue
-          return v
-        end
-        omit "Unused value not found in #{reg}" if fail
-      end
+      refute_predicate key, :created?
     end
   end
 end