Initial release: First & Last Frame Extractor for ComfyUI

A lightweight utility node that extracts the first and last frame from any video file or image batch. Supports dual input modes (file path + image batch), fallback sequential seeking, and is compatible with all ComfyUI versions.

test_node.py

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+"""Smoke tests for FirstFrameLastFrameExtractor."""
+import sys
+import os
+
+sys.path.insert(0, os.path.dirname(__file__))
+
+import torch
+from nodes import FirstFrameLastFrameExtractor
+
+
+def test_video_file():
+    """Test extraction from a real video file."""
+    node = FirstFrameLastFrameExtractor()
+    video = r"C:\Users\Virtual-Pc\Desktop\Future Egypt Veo3.mp4"
+    if not os.path.isfile(video):
+        print("SKIP: test video not found")
+        return
+
+    first, last = node.extract_frames(video_path=video)
+    assert first.dim() == 4, f"Expected 4D, got {first.dim()}D"
+    assert last.dim() == 4, f"Expected 4D, got {last.dim()}D"
+    assert first.shape[0] == 1
+    assert first.shape[3] == 3
+    assert first.dtype == torch.float32
+    assert 0.0 <= first.min() and first.max() <= 1.0
+    print(f"  Video file: first={list(first.shape)}, last={list(last.shape)}  OK")
+
+
+def test_image_batch():
+    """Test extraction from a fake image batch."""
+    node = FirstFrameLastFrameExtractor()
+    batch = torch.rand(10, 64, 64, 3)
+    first, last = node.extract_frames(images=batch)
+    assert torch.equal(first.squeeze(0), batch[0])
+    assert torch.equal(last.squeeze(0), batch[-1])
+    assert first.shape == torch.Size([1, 64, 64, 3])
+    print(f"  Image batch: first={list(first.shape)}, last={list(last.shape)}  OK")
+
+
+def test_single_frame_batch():
+    """Edge case: batch with only one frame."""
+    node = FirstFrameLastFrameExtractor()
+    batch = torch.rand(1, 32, 32, 3)
+    first, last = node.extract_frames(images=batch)
+    assert torch.equal(first, last), "Single-frame: first and last must be identical"
+    print("  Single-frame batch: OK")
+
+
+def test_error_empty_input():
+    """Should raise ValueError when nothing is provided."""
+    node = FirstFrameLastFrameExtractor()
+    try:
+        node.extract_frames(video_path="", images=None)
+        assert False, "Should have raised ValueError"
+    except ValueError:
+        print("  Empty input ValueError: OK")
+
+
+def test_error_missing_file():
+    """Should raise FileNotFoundError for non-existent path."""
+    node = FirstFrameLastFrameExtractor()
+    try:
+        node.extract_frames(video_path="C:/nonexistent/fake.mp4")
+        assert False, "Should have raised FileNotFoundError"
+    except FileNotFoundError:
+        print("  Missing file FileNotFoundError: OK")
+
+
+def test_error_whitespace():
+    """Should raise ValueError for whitespace-only path."""
+    node = FirstFrameLastFrameExtractor()
+    try:
+        node.extract_frames(video_path="   ")
+        assert False, "Should have raised ValueError"
+    except ValueError:
+        print("  Whitespace ValueError: OK")
+
+
+def test_quoted_path():
+    """Should strip surrounding quotes from path."""
+    node = FirstFrameLastFrameExtractor()
+    video = r"C:\Users\Virtual-Pc\Desktop\Future Egypt Veo3.mp4"
+    if not os.path.isfile(video):
+        print("  SKIP: test video not found")
+        return
+
+    first, last = node.extract_frames(video_path=f'"{video}"')
+    assert first.dim() == 4
+    print("  Quoted path stripping: OK")
+
+
+if __name__ == "__main__":
+    print("Running smoke tests...\n")
+    tests = [
+        test_video_file,
+        test_image_batch,
+        test_single_frame_batch,
+        test_error_empty_input,
+        test_error_missing_file,
+        test_error_whitespace,
+        test_quoted_path,
+    ]
+    passed = 0
+    failed = 0
+    for t in tests:
+        try:
+            t()
+            passed += 1
+        except Exception as e:
+            print(f"  FAIL {t.__name__}: {e}")
+            failed += 1
+
+    print(f"\nResults: {passed} passed, {failed} failed")
+    sys.exit(1 if failed else 0)