[tests] migrate test_hooks.py to pytest (#13242)

* move test_hooks.py to pytest

* Create `TestHooks` generator on `torch_device` (#13871)

Create TestHooks generator on device to avoid device mismatch errors

---------

Co-authored-by: dg845 <58458699+dg845@users.noreply.github.com>

Author: sayakpaul

tests/hooks/test_hooks.py

@@ -13,8 +13,8 @@
 # limitations under the License.
 
 import gc
-import unittest
 
+import pytest
 import torch
 
 from diffusers.hooks import HookRegistry, ModelHook
@@ -134,20 +134,18 @@ def post_forward(self, module, output):
         return output
 
 
-class HookTests(unittest.TestCase):
+class TestHooks:
     in_features = 4
     hidden_features = 8
     out_features = 4
     num_layers = 2
 
-    def setUp(self):
+    def setup_method(self):
         params = self.get_module_parameters()
         self.model = DummyModel(**params)
         self.model.to(torch_device)
 
-    def tearDown(self):
-        super().tearDown()
-
+    def teardown_method(self):
         del self.model
         gc.collect()
         free_memory()
@@ -161,7 +159,7 @@ def get_module_parameters(self):
         }
 
     def get_generator(self):
-        return torch.manual_seed(0)
+        return torch.Generator(device=torch_device).manual_seed(0)
 
     def test_hook_registry(self):
         registry = HookRegistry.check_if_exists_or_initialize(self.model)
@@ -171,20 +169,20 @@ def test_hook_registry(self):
         registry_repr = repr(registry)
         expected_repr = "HookRegistry(\n  (0) add_hook - AddHook\n  (1) multiply_hook - MultiplyHook(value=2)\n)"
 
-        self.assertEqual(len(registry.hooks), 2)
-        self.assertEqual(registry._hook_order, ["add_hook", "multiply_hook"])
-        self.assertEqual(registry_repr, expected_repr)
+        assert len(registry.hooks) == 2
+        assert registry._hook_order == ["add_hook", "multiply_hook"]
+        assert registry_repr == expected_repr
 
         registry.remove_hook("add_hook")
 
-        self.assertEqual(len(registry.hooks), 1)
-        self.assertEqual(registry._hook_order, ["multiply_hook"])
+        assert len(registry.hooks) == 1
+        assert registry._hook_order == ["multiply_hook"]
 
     def test_stateful_hook(self):
         registry = HookRegistry.check_if_exists_or_initialize(self.model)
         registry.register_hook(StatefulAddHook(1), "stateful_add_hook")
 
-        self.assertEqual(registry.hooks["stateful_add_hook"].increment, 0)
+        assert registry.hooks["stateful_add_hook"].increment == 0
 
         input = torch.randn(1, 4, device=torch_device, generator=self.get_generator())
         num_repeats = 3
@@ -194,13 +192,13 @@ def test_stateful_hook(self):
             if i == 0:
                 output1 = result
 
-        self.assertEqual(registry.get_hook("stateful_add_hook").increment, num_repeats)
+        assert registry.get_hook("stateful_add_hook").increment == num_repeats
 
         registry.reset_stateful_hooks()
         output2 = self.model(input)
 
-        self.assertEqual(registry.get_hook("stateful_add_hook").increment, 1)
-        self.assertTrue(torch.allclose(output1, output2))
+        assert registry.get_hook("stateful_add_hook").increment == 1
+        assert torch.allclose(output1, output2)
 
     def test_inference(self):
         registry = HookRegistry.check_if_exists_or_initialize(self.model)
@@ -218,40 +216,39 @@ def test_inference(self):
         new_input = input * 2 + 1
         output3 = self.model(new_input).mean().detach().cpu().item()
 
-        self.assertAlmostEqual(output1, output2, places=5)
-        self.assertAlmostEqual(output1, output3, places=5)
-        self.assertAlmostEqual(output2, output3, places=5)
+        assert output1 == pytest.approx(output2, abs=5e-6)
+        assert output1 == pytest.approx(output3, abs=5e-6)
+        assert output2 == pytest.approx(output3, abs=5e-6)
 
     def test_skip_layer_hook(self):
         registry = HookRegistry.check_if_exists_or_initialize(self.model)
         registry.register_hook(SkipLayerHook(skip_layer=True), "skip_layer_hook")
 
         input = torch.zeros(1, 4, device=torch_device)
         output = self.model(input).mean().detach().cpu().item()
-        self.assertEqual(output, 0.0)
+        assert output == 0.0
 
         registry.remove_hook("skip_layer_hook")
         registry.register_hook(SkipLayerHook(skip_layer=False), "skip_layer_hook")
         output = self.model(input).mean().detach().cpu().item()
-        self.assertNotEqual(output, 0.0)
+        assert output != 0.0
 
     def test_skip_layer_internal_block(self):
         registry = HookRegistry.check_if_exists_or_initialize(self.model.linear_1)
         input = torch.zeros(1, 4, device=torch_device)
 
         registry.register_hook(SkipLayerHook(skip_layer=True), "skip_layer_hook")
-        with self.assertRaises(RuntimeError) as cm:
+        with pytest.raises(RuntimeError, match="mat1 and mat2 shapes cannot be multiplied"):
             self.model(input).mean().detach().cpu().item()
-        self.assertIn("mat1 and mat2 shapes cannot be multiplied", str(cm.exception))
 
         registry.remove_hook("skip_layer_hook")
         output = self.model(input).mean().detach().cpu().item()
-        self.assertNotEqual(output, 0.0)
+        assert output != 0.0
 
         registry = HookRegistry.check_if_exists_or_initialize(self.model.blocks[1])
         registry.register_hook(SkipLayerHook(skip_layer=True), "skip_layer_hook")
         output = self.model(input).mean().detach().cpu().item()
-        self.assertNotEqual(output, 0.0)
+        assert output != 0.0
 
     def test_invocation_order_stateful_first(self):
         registry = HookRegistry.check_if_exists_or_initialize(self.model)
@@ -278,7 +275,7 @@ def test_invocation_order_stateful_first(self):
             .replace(" ", "")
             .replace("\n", "")
         )
-        self.assertEqual(output, expected_invocation_order_log)
+        assert output == expected_invocation_order_log
 
         registry.remove_hook("add_hook")
         with CaptureLogger(logger) as cap_logger:
@@ -289,7 +286,7 @@ def test_invocation_order_stateful_first(self):
             .replace(" ", "")
             .replace("\n", "")
         )
-        self.assertEqual(output, expected_invocation_order_log)
+        assert output == expected_invocation_order_log
 
     def test_invocation_order_stateful_middle(self):
         registry = HookRegistry.check_if_exists_or_initialize(self.model)
@@ -316,7 +313,7 @@ def test_invocation_order_stateful_middle(self):
             .replace(" ", "")
             .replace("\n", "")
         )
-        self.assertEqual(output, expected_invocation_order_log)
+        assert output == expected_invocation_order_log
 
         registry.remove_hook("add_hook")
         with CaptureLogger(logger) as cap_logger:
@@ -327,7 +324,7 @@ def test_invocation_order_stateful_middle(self):
             .replace(" ", "")
             .replace("\n", "")
         )
-        self.assertEqual(output, expected_invocation_order_log)
+        assert output == expected_invocation_order_log
 
         registry.remove_hook("add_hook_2")
         with CaptureLogger(logger) as cap_logger:
@@ -336,7 +333,7 @@ def test_invocation_order_stateful_middle(self):
         expected_invocation_order_log = (
             ("MultiplyHook pre_forward\nMultiplyHook post_forward\n").replace(" ", "").replace("\n", "")
         )
-        self.assertEqual(output, expected_invocation_order_log)
+        assert output == expected_invocation_order_log
 
     def test_invocation_order_stateful_last(self):
         registry = HookRegistry.check_if_exists_or_initialize(self.model)
@@ -363,7 +360,7 @@ def test_invocation_order_stateful_last(self):
             .replace(" ", "")
             .replace("\n", "")
         )
-        self.assertEqual(output, expected_invocation_order_log)
+        assert output == expected_invocation_order_log
 
         registry.remove_hook("add_hook")
         with CaptureLogger(logger) as cap_logger:
@@ -374,4 +371,4 @@ def test_invocation_order_stateful_last(self):
             .replace(" ", "")
             .replace("\n", "")
         )
-        self.assertEqual(output, expected_invocation_order_log)
+        assert output == expected_invocation_order_log