Fix timing assertion issue in test for pydash.delay where it could fa…

…il on certain environments.

Fixes #175

tests/test_functions.py

@@ -178,13 +178,10 @@ def func():
     "func,wait,args,kwargs,expected",
     [(lambda a, b, c: (a, b, c), 250, (1, 2), {"c": 3}, (1, 2, 3))],
 )
-def test_delay(func, wait, args, kwargs, expected):
-    start = time.time() * 1000
+def test_delay(mock_sleep, func, wait, args, kwargs, expected):
     result = _.delay(func, wait, *args, **kwargs)
-    stop = time.time() * 1000
-
-    assert (wait - 10) <= (stop - start) <= (wait + 10)
     assert result == expected
+    assert mock_sleep.call_args_list == [mock.call(pytest.approx(wait / 1000.0))]
 
 
 @parametrize(