Test that code length grows appropriately with value magnitude.

Test coeff_token0 table has correct structure.

Test generating bitstream from frame.

Test in-place compression.

Test that cosine matrix is approximately orthogonal.

Test that cosines matrix has correct shape.

Test count_bits helper function.

Test that constant block with matching DC neighbor uses DC mode.

Test dct1 computes single coefficient correctly.

Test DCT of constant block concentrates energy in DC.

Test DCT followed by IDCT returns original. Note: The dct2/idct2 functions are buggy reference implementations. The productio

Test DCT operation on all blocks in macroblock.

Test that DCT preserves energy (Parseval's theorem).

Test DCT/IDCT with constant block (DC only).

Test DCT/IDCT with gradient pattern.

Test that DCT followed by IDCT returns original data.

Test that DCT is linear: DCT(a*x + b*y) = a*DCT(x) + b*DCT(y).

Test decoder handles invalid VLC gracefully.

Test that decode is inverse of encode.

Test in-place decompression.

Test cosines generation for different block sizes.

Test creating macroblock with None data.

Test decoder handles empty/short VLC.

Test encoding of negative integers.

Test encoding of positive integers.

Test encoding of zero.

Test decoding a VLC back to block.

Test encoding a 4x4 block.

Test that decoder returns remaining bits correctly.

Test roundtrip with all-zero block.

Test Frame construction without data.

Test Frame construction with image data.

Test Frame with custom dimensions.

Test Frame with default dimensions.

Test frame bitstream generation.

Test frame image reconstruction.

Test frame bitstream decoding.

Test iterating over frame slices.

Test correct hierarchy: Frame -> Slice -> MacroBlock.

Test H264 with custom dimensions.

Test H264 object initialization.

Test that horizontal gradient selects H prediction when left column matches.

Test idct1 computes single spatial value correctly.

Test IDCT operation on all blocks in macroblock.

Test intra_predict returns a valid prediction mode.

Test that intra_predict returns a valid mode string.

Test that prediction mode is set on all transform blocks.

Test that intra_predict modifies blocks to contain residuals.

Test that vertical gradient data chooses V prediction.

Test lambda scaling function.

Test encoding large negative values.

Test encoding large positive values.

Test loading a test pattern.

Test loading pattern with custom generator.

Test loading Y4M video file.

Test that LUTs are properly initialized.

Test MacroBlock correctly partitions into 16 TransformBlocks.

Test get_image returns original data.

Test VLC encoding/decoding of entire macroblock.

Test handling of all-255 block.

Test that neighbor access returns correct shapes.

Generate and encode a test pattern.

Test that codes are prefix-free (no code is prefix of another).

Test quantization/dequantization introduces acceptable loss.

Test prediction with random data.

Test right_column accessor returns correct pixels.

Test right_column returns correct values.

Test that encode/decode roundtrip preserves data approximately.

Test slice with single macroblock.

Test DCT of block with single non-zero pixel.

Test frame with single slice.

Test Slice construction without data.

Test Slice construction with image data.

Test slice bitstream generation.

Test that slice supports indexing.

Test slice bitstream decoding.

Test slice string representation.

Test that slice stores width correctly.

Test that smaller values have shorter codes.

Test that operations enforce correct state transitions.

Test Table_run has correct structure.

Test Table_zeros has correct structure.

Test frame with many slices.

Test that vertical gradient selects V prediction when top row matches.

Test VLC encoding and decoding roundtrip.

Test slice with many macroblocks.

Test DCT of zero block.

Test handling of all-zero block.

Test that perfect prediction produces zero residual.

Test that DC coefficient (0,0) is first in zigzag order.

Test that highest frequency coefficient (3,3) is last.

Test that zigzag produces 16 elements from 4x4 block.

Test that zigzag produces correct coefficient ordering.

Test zigzag works with numpy arrays.