4 files changed, 76 insertions, 0 deletions
diff --git a/test/lib/!Nothing_to_test.rb b/test/lib/!Nothing_to_test.rb
new file mode 100644
index 0000000000..c1f4c439d3
--- /dev/null
+++ b/test/lib/!Nothing_to_test.rb
@@ -0,0 +1,5 @@
+### Empty test file for chkbuild ###
+
+# If chkbuild fails with `test-all`, each child file/directory is
+# executed individually, but test-unit fails if there are no test
+# files in the specified directory.
diff --git a/test/lib/jit_support.rb b/test/lib/jit_support.rb
new file mode 100644
index 0000000000..386a5a6f1e
--- /dev/null
+++ b/test/lib/jit_support.rb
@@ -0,0 +1,29 @@
+require 'rbconfig'
+
+module JITSupport
+  module_function
+
+  def yjit_supported?
+    return @yjit_supported if defined?(@yjit_supported)
+    # nil in mswin
+    @yjit_supported = ![nil, 'no'].include?(RbConfig::CONFIG['YJIT_SUPPORT'])
+  end
+
+  def yjit_enabled?
+    defined?(RubyVM::YJIT) && RubyVM::YJIT.enabled?
+  end
+
+  def yjit_force_enabled?
+    "#{RbConfig::CONFIG['CFLAGS']} #{RbConfig::CONFIG['CPPFLAGS']}".match?(/(\A|\s)-D ?YJIT_FORCE_ENABLE\b/)
+  end
+
+  def zjit_supported?
+    return @zjit_supported if defined?(@zjit_supported)
+    # nil in mswin
+    @zjit_supported = ![nil, 'no'].include?(RbConfig::CONFIG['ZJIT_SUPPORT'])
+  end
+
+  def zjit_enabled?
+    defined?(RubyVM::ZJIT) && RubyVM::ZJIT.enabled?
+  end
+end
diff --git a/test/lib/parser_support.rb b/test/lib/parser_support.rb
new file mode 100644
index 0000000000..0daf45e87b
--- /dev/null
+++ b/test/lib/parser_support.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module ParserSupport
+  module_function
+
+  # Determines whether or not Prism is being used in the current process. This
+  # would have been determined by `--parser=prism` on either the command line or
+  # from within various environment variables.
+  def prism_enabled?
+    RubyVM::InstructionSequence.compile("").to_a[4][:parser] == :prism
+  end
+
+  # Determines whether or not Prism would be used by a subprocess. This is
+  # necessary because some tests run in subprocesses, and we need to know if we
+  # expect Prism to be used by those tests. This happens if Prism is configured
+  # as the default parser.
+  def prism_enabled_in_subprocess?
+    EnvUtil.invoke_ruby(["-v"], "", true, false)[0].include?("+PRISM")
+  end
+end
diff --git a/test/lib/with_different_ofs.rb b/test/lib/with_different_ofs.rb
new file mode 100644
index 0000000000..559ed6a1d1
--- /dev/null
+++ b/test/lib/with_different_ofs.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+module DifferentOFS
+  module WithDifferentOFS
+    def setup
+      super
+      verbose, $VERBOSE = $VERBOSE, nil
+      @ofs, $, = $,, "-"
+      $VERBOSE = verbose
+    end
+    def teardown
+      verbose, $VERBOSE = $VERBOSE, nil
+      $, = @ofs
+      $VERBOSE = verbose
+      super
+    end
+  end
+
+  def self.extended(klass)
+    super(klass)
+    klass.const_set(:DifferentOFS, Class.new(klass).class_eval {include WithDifferentOFS}).name
+  end
+end