[tests] test load_components in modular (#13245)

* test load_components.

* fix

* fix

* u[

* up

Author: sayakpaul

tests/modular_pipelines/test_modular_pipelines_common.py

@@ -5,6 +5,7 @@
 
 import pytest
 import torch
+from huggingface_hub import hf_hub_download
 
 import diffusers
 from diffusers import AutoModel, ComponentsManager, ModularPipeline, ModularPipelineBlocks
@@ -32,6 +33,33 @@
 )
 
 
+def _get_specified_components(path_or_repo_id, cache_dir=None):
+    if os.path.isdir(path_or_repo_id):
+        config_path = os.path.join(path_or_repo_id, "modular_model_index.json")
+    else:
+        try:
+            config_path = hf_hub_download(
+                repo_id=path_or_repo_id,
+                filename="modular_model_index.json",
+                local_dir=cache_dir,
+            )
+        except Exception:
+            return None
+
+    with open(config_path) as f:
+        config = json.load(f)
+
+    components = set()
+    for k, v in config.items():
+        if isinstance(v, (str, int, float, bool)):
+            continue
+        for entry in v:
+            if isinstance(entry, dict) and (entry.get("repo") or entry.get("pretrained_model_name_or_path")):
+                components.add(k)
+                break
+    return components
+
+
 class ModularPipelineTesterMixin:
     """
     It provides a set of common tests for each modular pipeline,
@@ -360,6 +388,39 @@ def test_save_from_pretrained(self, tmp_path):
 
         assert torch.abs(image_slices[0] - image_slices[1]).max() < 1e-3
 
+    def test_load_expected_components_from_pretrained(self, tmp_path):
+        pipe = self.get_pipeline()
+        expected = _get_specified_components(self.pretrained_model_name_or_path, cache_dir=tmp_path)
+        if not expected:
+            pytest.skip("Skipping test as we couldn't fetch the expected components.")
+
+        actual = {
+            name
+            for name in pipe.components
+            if getattr(pipe, name, None) is not None
+            and getattr(getattr(pipe, name), "_diffusers_load_id", None) not in (None, "null")
+        }
+        assert expected == actual, f"Component mismatch: missing={expected - actual}, unexpected={actual - expected}"
+
+    def test_load_expected_components_from_save_pretrained(self, tmp_path):
+        pipe = self.get_pipeline()
+        save_dir = str(tmp_path / "saved-pipeline")
+        pipe.save_pretrained(save_dir)
+
+        expected = _get_specified_components(save_dir)
+        loaded_pipe = ModularPipeline.from_pretrained(save_dir)
+        loaded_pipe.load_components(torch_dtype=torch.float32)
+
+        actual = {
+            name
+            for name in loaded_pipe.components
+            if getattr(loaded_pipe, name, None) is not None
+            and getattr(getattr(loaded_pipe, name), "_diffusers_load_id", None) not in (None, "null")
+        }
+        assert expected == actual, (
+            f"Component mismatch after save/load: missing={expected - actual}, unexpected={actual - expected}"
+        )
+
     def test_modular_index_consistency(self, tmp_path):
         pipe = self.get_pipeline()
         components_spec = pipe._component_specs