[Tests] Add single file tester mixin for Models and remove unittest dependency (#12352)

* update

* update

* update

* update

* update

tests/single_file/test_stable_diffusion_xl_img2img_single_file.py

 import gc
-import unittest
 
 import torch
 
@@ -25,7 +24,7 @@ enable_full_determinism()
 
 @slow
 @require_torch_accelerator
-class StableDiffusionXLImg2ImgPipelineSingleFileSlowTests(unittest.TestCase, SDXLSingleFileTesterMixin):
+class TestStableDiffusionXLImg2ImgPipelineSingleFileSlow(SDXLSingleFileTesterMixin):
     pipeline_class = StableDiffusionXLImg2ImgPipeline
     ckpt_path = "https://huggingface.co/stabilityai/stable-diffusion-xl-base-1.0/blob/main/sd_xl_base_1.0.safetensors"
     repo_id = "stabilityai/stable-diffusion-xl-base-1.0"
@@ -33,13 +32,11 @@ class StableDiffusionXLImg2ImgPipelineSingleFileSlowTests(unittest.TestCase, SDX
         "https://raw.githubusercontent.com/Stability-AI/generative-models/main/configs/inference/sd_xl_base.yaml"
     )
 
-    def setUp(self):
-        super().setUp()
+    def setup_method(self):
         gc.collect()
         backend_empty_cache(torch_device)
 
-    def tearDown(self):
-        super().tearDown()
+    def teardown_method(self):
         gc.collect()
         backend_empty_cache(torch_device)
 
@@ -66,7 +63,7 @@ class StableDiffusionXLImg2ImgPipelineSingleFileSlowTests(unittest.TestCase, SDX
 
 @slow
 @require_torch_accelerator
-class StableDiffusionXLImg2ImgRefinerPipelineSingleFileSlowTests(unittest.TestCase):
+class StableDiffusionXLImg2ImgRefinerPipelineSingleFileSlowTests:
     pipeline_class = StableDiffusionXLImg2ImgPipeline
     ckpt_path = (
         "https://huggingface.co/stabilityai/stable-diffusion-xl-refiner-1.0/blob/main/sd_xl_refiner_1.0.safetensors"

tests/single_file/test_stable_diffusion_xl_instruct_pix2pix.py

 import gc
-import unittest
 
 import torch
 
@@ -19,19 +18,17 @@ enable_full_determinism()
 
 @slow
 @require_torch_accelerator
-class StableDiffusionXLInstructPix2PixPipeline(unittest.TestCase):
+class StableDiffusionXLInstructPix2PixPipeline:
     pipeline_class = StableDiffusionXLInstructPix2PixPipeline
     ckpt_path = "https://huggingface.co/stabilityai/cosxl/blob/main/cosxl_edit.safetensors"
     original_config = None
     repo_id = "diffusers/sdxl-instructpix2pix-768"
 
-    def setUp(self):
-        super().setUp()
+    def setup_method(self):
         gc.collect()
         backend_empty_cache(torch_device)
 
-    def tearDown(self):
-        super().tearDown()
+    def teardown_method(self):
         gc.collect()
         backend_empty_cache(torch_device)
 

tests/single_file/test_stable_diffusion_xl_single_file.py

 import gc
-import unittest
 
 import torch
 
@@ -22,7 +21,7 @@ enable_full_determinism()
 
 @slow
 @require_torch_accelerator
-class StableDiffusionXLPipelineSingleFileSlowTests(unittest.TestCase, SDXLSingleFileTesterMixin):
+class TestStableDiffusionXLPipelineSingleFileSlow(SDXLSingleFileTesterMixin):
     pipeline_class = StableDiffusionXLPipeline
     ckpt_path = "https://huggingface.co/stabilityai/stable-diffusion-xl-base-1.0/blob/main/sd_xl_base_1.0.safetensors"
     repo_id = "stabilityai/stable-diffusion-xl-base-1.0"
@@ -30,13 +29,11 @@ class StableDiffusionXLPipelineSingleFileSlowTests(unittest.TestCase, SDXLSingle
         "https://raw.githubusercontent.com/Stability-AI/generative-models/main/configs/inference/sd_xl_base.yaml"
     )
 
-    def setUp(self):
-        super().setUp()
+    def setup_method(self):
         gc.collect()
         backend_empty_cache(torch_device)
 
-    def tearDown(self):
-        super().tearDown()
+    def teardown_method(self):
         gc.collect()
         backend_empty_cache(torch_device)