[tests] fix Pixart Sigma tests (#7966)

* checking tests

* checking ii.

* remove prints.

* test_pixart_1024

* fix 1024.

Author: sayakpaul

tests/pipelines/pixart_sigma/test_pixart.py

@@ -336,23 +336,28 @@ def test_pixart_1024(self):
         image = pipe(prompt, generator=generator, num_inference_steps=2, output_type="np").images
 
         image_slice = image[0, -3:, -3:, -1]
-        expected_slice = np.array([0.0742, 0.0835, 0.2114, 0.0295, 0.0784, 0.2361, 0.1738, 0.2251, 0.3589])
+        expected_slice = np.array([0.4517, 0.4446, 0.4375, 0.449, 0.4399, 0.4365, 0.4583, 0.4629, 0.4473])
 
         max_diff = numpy_cosine_similarity_distance(image_slice.flatten(), expected_slice)
         self.assertLessEqual(max_diff, 1e-4)
 
     def test_pixart_512(self):
         generator = torch.Generator("cpu").manual_seed(0)
 
-        pipe = PixArtSigmaPipeline.from_pretrained(self.ckpt_id_512, torch_dtype=torch.float16)
+        transformer = Transformer2DModel.from_pretrained(
+            self.ckpt_id_512, subfolder="transformer", torch_dtype=torch.float16
+        )
+        pipe = PixArtSigmaPipeline.from_pretrained(
+            self.ckpt_id_1024, transformer=transformer, torch_dtype=torch.float16
+        )
         pipe.enable_model_cpu_offload()
 
         prompt = self.prompt
 
         image = pipe(prompt, generator=generator, num_inference_steps=2, output_type="np").images
 
         image_slice = image[0, -3:, -3:, -1]
-        expected_slice = np.array([0.3477, 0.3882, 0.4541, 0.3413, 0.3821, 0.4463, 0.4001, 0.4409, 0.4958])
+        expected_slice = np.array([0.0479, 0.0378, 0.0217, 0.0942, 0.064, 0.0791, 0.2073, 0.1975, 0.2017])
 
         max_diff = numpy_cosine_similarity_distance(image_slice.flatten(), expected_slice)
         self.assertLessEqual(max_diff, 1e-4)
@@ -394,7 +399,12 @@ def test_pixart_1024_without_resolution_binning(self):
     def test_pixart_512_without_resolution_binning(self):
         generator = torch.manual_seed(0)
 
-        pipe = PixArtSigmaPipeline.from_pretrained(self.ckpt_id_512, torch_dtype=torch.float16)
+        transformer = Transformer2DModel.from_pretrained(
+            self.ckpt_id_512, subfolder="transformer", torch_dtype=torch.float16
+        )
+        pipe = PixArtSigmaPipeline.from_pretrained(
+            self.ckpt_id_1024, transformer=transformer, torch_dtype=torch.float16
+        )
         pipe.enable_model_cpu_offload()
 
         prompt = self.prompt