From eabed7c763c7b2c38be9899730b3ec1969cfc52c Mon Sep 17 00:00:00 2001
From: Danny McClanahan <1305167+cosmicexplorer@users.noreply.github.com>
Date: Sun, 20 Oct 2019 15:12:08 -0700
Subject: [PATCH] add tests for @sentinel_attribute

---
 tests/python/pants_test/util/test_meta.py | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/tests/python/pants_test/util/test_meta.py b/tests/python/pants_test/util/test_meta.py
index ada93fa34a3a..f23c0921137e 100644
--- a/tests/python/pants_test/util/test_meta.py
+++ b/tests/python/pants_test/util/test_meta.py
@@ -5,7 +5,8 @@
 from abc import ABC, abstractmethod
 from dataclasses import FrozenInstanceError, dataclass
 
-from pants.util.meta import SingletonMetaclass, classproperty, frozen_after_init, staticproperty
+from pants.util.meta import (SingletonMetaclass, classproperty, frozen_after_init,
+                             sentinel_attribute, staticproperty)
 from pants_test.test_base import TestBase
 
 
@@ -246,6 +247,22 @@ def f(cls):
     self.assertEqual(Concrete2.f, 'hello')
 
 
+class SentinelAttributeTest(unittest.TestCase):
+
+  def test_sentinel_attribute(self):
+    @sentinel_attribute('_test_attr_name')
+    def f(cls):
+      return f.define_instance_of(cls)
+
+    @f
+    class C:
+      pass
+
+    self.assertEqual(f.sentinel_attribute, '_test_attr_name')
+    self.assertTrue(C._test_attr_name)
+    self.assertTrue(f.is_instance(C))
+
+
 class FrozenAfterInitTest(unittest.TestCase):
 
   def test_no_init(self) -> None: