test(Slot): cover __repr__

Issue: #4324

scrapy/core/downloader/__init__.py

@@ -43,7 +43,7 @@ class Slot:
         cls_name = self.__class__.__name__
         return (f"{cls_name}(concurrency={self.concurrency!r}, "
                 f"delay={self.delay:.2f}, "
-                f"randomize_delay={self.randomize_delay!r}")
+                f"randomize_delay={self.randomize_delay!r})")
 
     def __str__(self):
         return (

tests/test_core_downloader.py

@@ -0,0 +1,10 @@
+from twisted.trial import unittest
+
+from scrapy.core.downloader import Slot
+
+
+class SlotTest(unittest.TestCase):
+
+    def test_repr(self):
+        slot = Slot(concurrency=8, delay=0.1, randomize_delay=True)
+        self.assertEqual(repr(slot), 'Slot(concurrency=8, delay=0.10, randomize_delay=True)')