[Tests] Improve transformers model test suite coverage - Lumina (#8987)

* Added test suite for lumina

* Fixed failing tests

* Improved code quality

* Added function docstrings

* Improved formatting

tests/models/transformers/test_models_transformer_lumina.py

+# coding=utf-8
+# Copyright 2024 HuggingFace Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+
+import torch
+
+from diffusers import LuminaNextDiT2DModel
+from diffusers.utils.testing_utils import (
+    enable_full_determinism,
+    torch_device,
+)
+
+from ..test_modeling_common import ModelTesterMixin
+
+
+enable_full_determinism()
+
+
+class LuminaNextDiT2DModelTransformerTests(ModelTesterMixin, unittest.TestCase):
+    model_class = LuminaNextDiT2DModel
+    main_input_name = "hidden_states"
+
+    @property
+    def dummy_input(self):
+        """
+        Args:
+            None
+        Returns:
+            Dict: Dictionary of dummy input tensors
+        """
+        batch_size = 2  # N
+        num_channels = 4  # C
+        height = width = 16  # H, W
+        embedding_dim = 32  # D
+        sequence_length = 16  # L
+
+        hidden_states = torch.randn((batch_size, num_channels, height, width)).to(torch_device)
+        encoder_hidden_states = torch.randn((batch_size, sequence_length, embedding_dim)).to(torch_device)
+        timestep = torch.rand(size=(batch_size,)).to(torch_device)
+        encoder_mask = torch.randn(size=(batch_size, sequence_length)).to(torch_device)
+        image_rotary_emb = torch.randn((384, 384, 4)).to(torch_device)
+
+        return {
+            "hidden_states": hidden_states,
+            "encoder_hidden_states": encoder_hidden_states,
+            "timestep": timestep,
+            "encoder_mask": encoder_mask,
+            "image_rotary_emb": image_rotary_emb,
+            "cross_attention_kwargs": {},
+        }
+
+    @property
+    def input_shape(self):
+        """
+        Args:
+            None
+        Returns:
+            Tuple: (int, int, int)
+        """
+        return (4, 16, 16)
+
+    @property
+    def output_shape(self):
+        """
+        Args:
+            None
+        Returns:
+            Tuple: (int, int, int)
+        """
+        return (4, 16, 16)
+
+    def prepare_init_args_and_inputs_for_common(self):
+        """
+        Args:
+            None
+
+        Returns:
+            Tuple: (Dict, Dict)
+        """
+        init_dict = {
+            "sample_size": 16,
+            "patch_size": 2,
+            "in_channels": 4,
+            "hidden_size": 24,
+            "num_layers": 2,
+            "num_attention_heads": 3,
+            "num_kv_heads": 1,
+            "multiple_of": 16,
+            "ffn_dim_multiplier": None,
+            "norm_eps": 1e-5,
+            "learn_sigma": False,
+            "qk_norm": True,
+            "cross_attention_dim": 32,
+            "scaling_factor": 1.0,
+        }
+
+        inputs_dict = self.dummy_input
+        return init_dict, inputs_dict