diff --git a/standalone_tests/close_on_fork_test.rb b/standalone_tests/close_on_fork_test.rb
new file mode 100644
index 00000000..47dd3b2c
--- /dev/null
+++ b/standalone_tests/close_on_fork_test.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "oj"
+require "test_helper"
+
+class CloseOnForkTest < Minitest::Test
+  include HTTPHelpers
+  include HTTPX
+
+  def test_close_on_fork_after_fork_callback
+    skip("MRI feature") unless Process.respond_to?(:fork)
+    GC.start # cleanup instances created by other tests
+
+    http = HTTPX.plugin(SessionWithPool).with(persistent: true, close_on_fork: true)
+    uri = URI(build_uri("/get"))
+    response = http.get(uri)
+    verify_status(response, 200)
+
+    assert http.connections.size == 1
+    assert http.connections.count { |c| c.state == :closed }.zero?, "should have no closed connections"
+    HTTPX::Session.after_fork
+    assert http.connections.size == 1
+    assert http.connections.count { |c| c.state == :closed } == 1, "should have a closed connection"
+  end
+
+  def test_close_on_fork_automatic_after_fork_callback
+    skip("MRI 3.1 feature") unless Process.respond_to?(:_fork)
+    GC.start # cleanup instances created by other tests
+
+    http = HTTPX.plugin(SessionWithPool).with(persistent: true, close_on_fork: true)
+    uri = URI(build_uri("/get"))
+    response = http.get(uri)
+    verify_status(response, 200)
+
+    assert http.connections.size == 1
+    assert http.connections.count { |c| c.state == :closed }.zero?, "should have no closed connections"
+    pid = fork do
+      assert http.connections.count { |c| c.state == :closed } == 1, "should have no closed connections"
+      exit!(0)
+    end
+    assert http.connections.count { |c| c.state == :closed }.zero?, "should have no closed connections"
+    _, status = Process.waitpid2(pid)
+    assert_predicate(status, :success?)
+  end
+
+  private
+
+  def scheme
+    "https://"
+  end
+
+  def request(verb = "GET", uri = "http://google.com", **args)
+    Request.new(verb, uri, Options.new, **args)
+  end
+
+  def response(*args)
+    Response.new(*args)
+  end
+end