diffusers/tests/models/transformers/test_models_transformer_chroma.py

# coding=utf-8
# Copyright 2025 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 ChromaTransformer2DModel
from diffusers.models.attention_processor import FluxIPAdapterJointAttnProcessor2_0
from diffusers.models.embeddings import ImageProjection
from diffusers.utils.testing_utils import enable_full_determinism, torch_device

from ..test_modeling_common import LoraHotSwappingForModelTesterMixin, ModelTesterMixin, TorchCompileTesterMixin


enable_full_determinism()


def create_chroma_ip_adapter_state_dict(model):
    # "ip_adapter" (cross-attention weights)
    ip_cross_attn_state_dict = {}
    key_id = 0

    for name in model.attn_processors.keys():
        if name.startswith("single_transformer_blocks"):
            continue

        joint_attention_dim = model.config["joint_attention_dim"]
        hidden_size = model.config["num_attention_heads"] * model.config["attention_head_dim"]
        sd = FluxIPAdapterJointAttnProcessor2_0(
            hidden_size=hidden_size, cross_attention_dim=joint_attention_dim, scale=1.0
        ).state_dict()
        ip_cross_attn_state_dict.update(
            {
                f"{key_id}.to_k_ip.weight": sd["to_k_ip.0.weight"],
                f"{key_id}.to_v_ip.weight": sd["to_v_ip.0.weight"],
                f"{key_id}.to_k_ip.bias": sd["to_k_ip.0.bias"],
                f"{key_id}.to_v_ip.bias": sd["to_v_ip.0.bias"],
            }
        )

        key_id += 1

    # "image_proj" (ImageProjection layer weights)

    image_projection = ImageProjection(
        cross_attention_dim=model.config["joint_attention_dim"],
        image_embed_dim=model.config["pooled_projection_dim"],
        num_image_text_embeds=4,
    )

    ip_image_projection_state_dict = {}
    sd = image_projection.state_dict()
    ip_image_projection_state_dict.update(
        {
            "proj.weight": sd["image_embeds.weight"],
            "proj.bias": sd["image_embeds.bias"],
            "norm.weight": sd["norm.weight"],
            "norm.bias": sd["norm.bias"],
        }
    )

    del sd
    ip_state_dict = {}
    ip_state_dict.update({"image_proj": ip_image_projection_state_dict, "ip_adapter": ip_cross_attn_state_dict})
    return ip_state_dict


class ChromaTransformerTests(ModelTesterMixin, unittest.TestCase):
    model_class = ChromaTransformer2DModel
    main_input_name = "hidden_states"
    # We override the items here because the transformer under consideration is small.
    model_split_percents = [0.8, 0.7, 0.7]

    # Skip setting testing with default: AttnProcessor
    uses_custom_attn_processor = True

    @property
    def dummy_input(self):
        batch_size = 1
        num_latent_channels = 4
        num_image_channels = 3
        height = width = 4
        sequence_length = 48
        embedding_dim = 32

        hidden_states = torch.randn((batch_size, height * width, num_latent_channels)).to(torch_device)
        encoder_hidden_states = torch.randn((batch_size, sequence_length, embedding_dim)).to(torch_device)
        text_ids = torch.randn((sequence_length, num_image_channels)).to(torch_device)
        image_ids = torch.randn((height * width, num_image_channels)).to(torch_device)
        timestep = torch.tensor([1.0]).to(torch_device).expand(batch_size)

        return {
            "hidden_states": hidden_states,
            "encoder_hidden_states": encoder_hidden_states,
            "img_ids": image_ids,
            "txt_ids": text_ids,
            "timestep": timestep,
        }

    @property
    def input_shape(self):
        return (16, 4)

    @property
    def output_shape(self):
        return (16, 4)

    def prepare_init_args_and_inputs_for_common(self):
        init_dict = {
            "patch_size": 1,
            "in_channels": 4,
            "num_layers": 1,
            "num_single_layers": 1,
            "attention_head_dim": 16,
            "num_attention_heads": 2,
            "joint_attention_dim": 32,
            "axes_dims_rope": [4, 4, 8],
            "approximator_num_channels": 8,
            "approximator_hidden_dim": 16,
            "approximator_layers": 1,
        }

        inputs_dict = self.dummy_input
        return init_dict, inputs_dict

    def test_deprecated_inputs_img_txt_ids_3d(self):
        init_dict, inputs_dict = self.prepare_init_args_and_inputs_for_common()
        model = self.model_class(**init_dict)
        model.to(torch_device)
        model.eval()

        with torch.no_grad():
            output_1 = model(**inputs_dict).to_tuple()[0]

        # update inputs_dict with txt_ids and img_ids as 3d tensors (deprecated)
        text_ids_3d = inputs_dict["txt_ids"].unsqueeze(0)
        image_ids_3d = inputs_dict["img_ids"].unsqueeze(0)

        assert text_ids_3d.ndim == 3, "text_ids_3d should be a 3d tensor"
        assert image_ids_3d.ndim == 3, "img_ids_3d should be a 3d tensor"

        inputs_dict["txt_ids"] = text_ids_3d
        inputs_dict["img_ids"] = image_ids_3d

        with torch.no_grad():
            output_2 = model(**inputs_dict).to_tuple()[0]

        self.assertEqual(output_1.shape, output_2.shape)
        self.assertTrue(
            torch.allclose(output_1, output_2, atol=1e-5),
            msg="output with deprecated inputs (img_ids and txt_ids as 3d torch tensors) are not equal as them as 2d inputs",
        )

    def test_gradient_checkpointing_is_applied(self):
        expected_set = {"ChromaTransformer2DModel"}
        super().test_gradient_checkpointing_is_applied(expected_set=expected_set)


class ChromaTransformerCompileTests(TorchCompileTesterMixin, unittest.TestCase):
    model_class = ChromaTransformer2DModel

    def prepare_init_args_and_inputs_for_common(self):
        return ChromaTransformerTests().prepare_init_args_and_inputs_for_common()


class ChromaTransformerLoRAHotSwapTests(LoraHotSwappingForModelTesterMixin, unittest.TestCase):
    model_class = ChromaTransformer2DModel

    def prepare_init_args_and_inputs_for_common(self):
        return ChromaTransformerTests().prepare_init_args_and_inputs_for_common()