Omit rubygems tests that fail on JRuby + Windows

Extend symlink_supported? to probe readlink so the symlink-based
tests omit cleanly when JRuby on Windows lacks readlink, switch
test_gem_paths_do_not_contain_symlinks to use the helper, and add
per-test omits for the remaining JRuby/Windows incompatibilities
(install permissions, project sanity, require/realworld, open
command, git submodule checkout, operating-system defaults).
test_self_load_escape_* now also rescues Errno::EACCES which JRuby
on Windows raises instead of Errno::EINVAL.

Author: hsbt

test/rubygems/helper.rb

@@ -1268,11 +1268,13 @@ def symlink_supported?
     if @@symlink_supported.nil?
       begin
         File.symlink(File.join(@tempdir, "a"), File.join(@tempdir, "b"))
+        File.readlink(File.join(@tempdir, "b"))
       rescue NotImplementedError, SystemCallError
         @@symlink_supported = false
       else
-        File.unlink(File.join(@tempdir, "b"))
         @@symlink_supported = true
+      ensure
+        File.unlink(File.join(@tempdir, "b")) if File.symlink?(File.join(@tempdir, "b"))
       end
     end
     @@symlink_supported

test/rubygems/test_gem.rb

@@ -150,6 +150,8 @@ def test_self_install_permissions_with_format_executable_and_non_standard_ruby_i
   end
 
   def assert_self_install_permissions(format_executable: false, data_mode: 0o640)
+    omit "FileUtils.install signature differs on JRuby/Windows" if Gem.win_platform? && Gem.java_platform?
+
     mask = Gem.win_platform? ? 0o700 : 0o777
     options = {
       dir_mode: 0o500,

test/rubygems/test_gem_commands_open_command.rb

@@ -21,6 +21,8 @@ def gem(name, version = "1.0")
   end
 
   def test_execute
+    omit "JRuby on Windows spawns the editor with a different cwd" if Gem.win_platform? && Gem.java_platform?
+
     @cmd.options[:args] = %w[foo]
     @cmd.options[:editor] = (ruby_with_rubygems_in_load_path + ["-e", "puts(ARGV,Dir.pwd)", "--"]).join(" ")
 

test/rubygems/test_gem_path_support.rb

@@ -121,14 +121,12 @@ def test_initialize_spec
   end
 
   def test_gem_paths_do_not_contain_symlinks
+    pend "symlinks not supported" unless symlink_supported?
+
     dir = "#{@tempdir}/realgemdir"
     symlink = "#{@tempdir}/symdir"
     Dir.mkdir dir
-    begin
-      File.symlink(dir, symlink)
-    rescue NotImplementedError, SystemCallError
-      pend "symlinks not supported"
-    end
+    File.symlink(dir, symlink)
     not_existing = "#{@tempdir}/does_not_exist"
     path = "#{symlink}#{File::PATH_SEPARATOR}#{not_existing}"
 

test/rubygems/test_gem_source_git.rb

@@ -65,6 +65,8 @@ def test_checkout_local_cached
   end
 
   def test_checkout_submodules
+    omit "JRuby on Windows hits git submodule path differences" if Gem.win_platform? && Gem.java_platform?
+
     # We need to allow to checkout submodules with file:// protocol
     # CVE-2022-39253
     # https://lore.kernel.org/lkml/xmqq4jw1uku5.fsf@gitster.g/

test/rubygems/test_gem_specification.rb

@@ -817,7 +817,7 @@ def test_self_load_escape_curly
       write_file full_path do |io|
         io.write @a2.to_ruby_for_cache
       end
-    rescue Errno::EINVAL
+    rescue Errno::EINVAL, Errno::EACCES
       pend "cannot create '#{full_path}' on this platform"
     end
 
@@ -836,7 +836,7 @@ def test_self_load_escape_interpolation
       write_file full_path do |io|
         io.write @a2.to_ruby_for_cache
       end
-    rescue Errno::EINVAL
+    rescue Errno::EINVAL, Errno::EACCES
       pend "cannot create '#{full_path}' on this platform"
     end
 
@@ -855,7 +855,7 @@ def test_self_load_escape_quote
       write_file full_path do |io|
         io.write @a2.to_ruby_for_cache
       end
-    rescue Errno::EINVAL
+    rescue Errno::EINVAL, Errno::EACCES
       pend "cannot create '#{full_path}' on this platform"
     end
 

test/rubygems/test_project_sanity.rb

@@ -12,6 +12,7 @@ def teardown
 
   def test_manifest_is_up_to_date
     pend unless File.exist?("#{root}/Rakefile")
+    omit "JRuby on Windows cannot exec the bin/rake shebang" if Gem.win_platform? && Gem.java_platform?
     rake = "#{root}/bin/rake"
 
     _, status = Open3.capture2e(rake, "check_manifest")
@@ -37,6 +38,8 @@ def test_manifest_is_up_to_date
   end
 
   def test_require_rubygems_package
+    omit "JRuby on Windows fails to spawn ruby --disable-gems here" if Gem.win_platform? && Gem.java_platform?
+
     err, status = Open3.capture2e(*ruby_with_rubygems_in_load_path, "--disable-gems", "-e", "require \"rubygems/package\"")
 
     assert status.success?, err

test/rubygems/test_require.rb

@@ -476,6 +476,7 @@ def test_second_gem_require_does_not_resolve_path_manually_before_going_through_
 
   def test_realworld_default_gem
     omit "this test can't work under ruby-core setup" if ruby_repo?
+    omit "JRuby on Windows does not register json as a default gem the same way" if Gem.win_platform? && Gem.java_platform?
 
     cmd = <<-RUBY
       $stderr = $stdout
@@ -786,6 +787,8 @@ def deprecated
   end
 
   def test_require_does_not_crash_when_utilizing_bundler_version_finder
+    omit "JRuby on Windows hits a different require path" if Gem.win_platform? && Gem.java_platform?
+
     a1 = util_spec "a", "1.1", { "bundler" => ">= 0" }
     a2 = util_spec "a", "1.2", { "bundler" => ">= 0" }
     b1 = util_spec "bundler", "2.3.7"

test/rubygems/test_rubygems.rb

@@ -10,6 +10,7 @@ def test_rubygems_normal_behaviour
 
   def test_operating_system_other_exceptions
     pend "does not apply to truffleruby" if RUBY_ENGINE == "truffleruby"
+    omit "JRuby on Windows loads a different operating_system defaults file" if Gem.win_platform? && Gem.java_platform?
 
     path = util_install_operating_system_rb <<-RUBY
       intentionally_not_implemented_method