diff --git a/tests/test_downloaderslotssettings.py b/tests/test_downloaderslotssettings.py
new file mode 100644
index 000000000..6ea03fb78
--- /dev/null
+++ b/tests/test_downloaderslotssettings.py
@@ -0,0 +1,75 @@
+import time
+
+from scrapy.crawler import CrawlerRunner
+from scrapy.http import Request
+
+from tests.mockserver import MockServer
+from tests.spiders import MetaSpider
+
+from twisted.internet import defer
+from twisted.trial.unittest import TestCase
+
+
+class DownloaderSlotsSettingsTestSpider(MetaSpider):
+
+    name = 'downloader_slots'
+
+    custom_settings = {
+        "DOWNLOAD_DELAY": 1,
+        "RANDOMIZE_DOWNLOAD_DELAY": False,
+        "DOWNLOAD_SLOTS": {
+            'quotes.toscrape.com': {
+                'concurrency': 1,
+                'delay': 1.5,
+                'randomize_delay': False
+            },
+            'books.toscrape.com': {
+                'delay': 2,
+                'randomize_delay': False
+            }
+        }
+    }
+
+    def start_requests(self):
+        self.times = {None: []}
+
+        slots = list(self.custom_settings.get('DOWNLOAD_SLOTS', {}).keys()) + [None]
+
+        for slot in slots:
+            url = self.mockserver.url(f"/?downloader_slot={slot}")
+            self.times[slot] = []
+            yield Request(url, callback=self.parse, meta={'download_slot': slot})
+
+    def parse(self, response):
+        slot = response.meta.get('download_slot', None)
+        self.times[slot].append(time.time())
+        url = self.mockserver.url(f"/?downloader_slot={slot}&req=2")
+        yield Request(url, callback=self.not_parse, meta={'download_slot': slot})
+
+    def not_parse(self, response):
+        slot = response.meta.get('download_slot', None)
+        self.times[slot].append(time.time())
+
+
+class CrawlTestCase(TestCase):
+
+    def setUp(self):
+        self.mockserver = MockServer()
+        self.mockserver.__enter__()
+        self.runner = CrawlerRunner()
+
+    def tearDown(self):
+        self.mockserver.__exit__(None, None, None)
+
+    @defer.inlineCallbacks
+    def test_delay(self):
+        crawler = CrawlerRunner().create_crawler(DownloaderSlotsSettingsTestSpider)
+        yield crawler.crawl(mockserver=self.mockserver)
+        slots = crawler.engine.downloader.slots
+        times = crawler.spider.times
+        tolerance = 0.3
+
+        delays_real = {k: v[1] - v[0] for k, v in times.items()}
+        error_delta = {k: 1 - delays_real[k] / v.delay for k, v in slots.items()}
+
+        self.assertTrue(max(list(error_delta.values())) < tolerance)