[test schedulers] adjust to test the first step's reading (#6429)

* [test schedulers] small improvement

* cleanup

tests/test_optimization.py

@@ -40,16 +40,16 @@ if is_torch_available():
 def unwrap_schedule(scheduler, num_steps=10):
     lrs = []
     for _ in range(num_steps):
+        lrs.append(scheduler.get_lr()[0])
         scheduler.step()
-        lrs.append(scheduler.get_lr())
     return lrs
 
 
 def unwrap_and_save_reload_schedule(scheduler, num_steps=10):
     lrs = []
     for step in range(num_steps):
+        lrs.append(scheduler.get_lr()[0])
         scheduler.step()
-        lrs.append(scheduler.get_lr())
         if step == num_steps // 2:
             with tempfile.TemporaryDirectory() as tmpdirname:
                 file_name = os.path.join(tmpdirname, "schedule.bin")
@@ -127,23 +127,23 @@ class ScheduleInitTest(unittest.TestCase):
             get_constant_schedule: ({}, [10.0] * self.num_steps),
             get_constant_schedule_with_warmup: (
                 {"num_warmup_steps": 4},
-                [2.5, 5.0, 7.5, 10.0, 10.0, 10.0, 10.0, 10.0, 10.0, 10.0],
+                [0.0, 2.5, 5.0, 7.5, 10.0, 10.0, 10.0, 10.0, 10.0, 10.0],
             ),
             get_linear_schedule_with_warmup: (
                 {**common_kwargs},
-                [5.0, 10.0, 8.75, 7.5, 6.25, 5.0, 3.75, 2.5, 1.25, 0.0],
+                [0.0, 5.0, 10.0, 8.75, 7.5, 6.25, 5.0, 3.75, 2.5, 1.25],
             ),
             get_cosine_schedule_with_warmup: (
                 {**common_kwargs},
-                [5.0, 10.0, 9.61, 8.53, 6.91, 5.0, 3.08, 1.46, 0.38, 0.0],
+                [0.0, 5.0, 10.0, 9.61, 8.53, 6.91, 5.0, 3.08, 1.46, 0.38],
             ),
             get_cosine_with_hard_restarts_schedule_with_warmup: (
                 {**common_kwargs, "num_cycles": 2},
-                [5.0, 10.0, 8.53, 5.0, 1.46, 10.0, 8.53, 5.0, 1.46, 0.0],
+                [0.0, 5.0, 10.0, 8.53, 5.0, 1.46, 10.0, 8.53, 5.0, 1.46],
             ),
             get_polynomial_decay_schedule_with_warmup: (
                 {**common_kwargs, "power": 2.0, "lr_end": 1e-7},
-                [5.0, 10.0, 7.656, 5.625, 3.906, 2.5, 1.406, 0.625, 0.156, 1e-07],
+                [0.0, 5.0, 10.0, 7.656, 5.625, 3.906, 2.5, 1.406, 0.625, 0.156],
             ),
         }
 
@@ -151,17 +151,12 @@ class ScheduleInitTest(unittest.TestCase):
             kwargs, expected_learning_rates = data
 
             scheduler = scheduler_func(self.optimizer, **kwargs)
+            self.assertEqual(len([scheduler.get_lr()[0]]), 1)
             lrs_1 = unwrap_schedule(scheduler, self.num_steps)
-            self.assertEqual(len(lrs_1[0]), 1)
             self.assertListAlmostEqual(
-                [l[0] for l in lrs_1],
-                expected_learning_rates,
-                tol=1e-2,
-                msg=f"failed for {scheduler_func} in normal scheduler",
+                lrs_1, expected_learning_rates, tol=1e-2, msg=f"failed for {scheduler_func} in normal scheduler",
             )
 
             scheduler = scheduler_func(self.optimizer, **kwargs)
             lrs_2 = unwrap_and_save_reload_schedule(scheduler, self.num_steps)
-            self.assertListEqual(
-                [l[0] for l in lrs_1], [l[0] for l in lrs_2], msg=f"failed for {scheduler_func} in save and reload"
-            )
+            self.assertListEqual(lrs_1, lrs_2, msg=f"failed for {scheduler_func} in save and reload")