Bootstrap the repixelizer CLI project

tests/test_cli.py

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+from __future__ import annotations
+
+from pathlib import Path
+
+from repixelizer.cli import main
+from repixelizer.io import save_rgba
+from repixelizer.synthetic import fake_pixelize, make_emblem
+
+
+def test_default_command_runs_without_explicit_run_subcommand(tmp_path: Path) -> None:
+    source = make_emblem(16, 16)
+    fake = fake_pixelize(source, upscale=8, phase_x=0.2, phase_y=0.25, blur_radius=0.4)
+    input_path = tmp_path / "input.png"
+    output_path = tmp_path / "output.png"
+    save_rgba(input_path, fake)
+    exit_code = main([str(input_path), "--out", str(output_path), "--steps", "8"])
+    assert exit_code == 0
+    assert output_path.exists()

tests/test_compare.py

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+from __future__ import annotations
+
+from pathlib import Path
+
+from repixelizer.compare import run_compare
+from repixelizer.io import save_rgba
+from repixelizer.synthetic import fake_pixelize, make_emblem
+
+
+def test_compare_writes_comparison_artifacts(tmp_path: Path) -> None:
+    source = make_emblem(32, 32)
+    fake = fake_pixelize(source, upscale=10, phase_x=0.2, phase_y=0.3, blur_radius=0.5)
+    input_path = tmp_path / "input.png"
+    output_path = tmp_path / "output.png"
+    diagnostics_dir = tmp_path / "diagnostics"
+    save_rgba(input_path, fake)
+
+    payload = run_compare(input_path, output_path, diagnostics_dir=diagnostics_dir, steps=20)
+    assert output_path.exists()
+    assert (diagnostics_dir / "compare-sheet.png").exists()
+    assert (diagnostics_dir / "compare.csv").exists()
+    assert len(payload["rows"]) == 3

tests/test_inference.py

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+from __future__ import annotations
+
+from repixelizer.inference import infer_lattice
+from repixelizer.synthetic import fake_pixelize, make_emblem
+
+
+def test_infer_lattice_recovers_emblem_scale() -> None:
+    source = make_emblem(32, 32)
+    fake = fake_pixelize(source, upscale=12, phase_x=0.2, phase_y=0.35, blur_radius=0.6)
+    result = infer_lattice(fake)
+    assert result.target_width in range(28, 37)
+    assert result.target_height in range(28, 37)
+    assert result.confidence >= 0.0

tests/test_palette.py

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+from __future__ import annotations
+
+from pathlib import Path
+
+from repixelizer.palette import load_palette, quantize_rgba
+from repixelizer.synthetic import make_emblem
+
+
+def test_load_gpl_palette(tmp_path: Path) -> None:
+    palette_path = tmp_path / "palette.gpl"
+    palette_path.write_text(
+        "GIMP Palette\nName: Test\nColumns: 2\n255 0 0 Red\n0 255 0 Green\n",
+        encoding="utf-8",
+    )
+    palette = load_palette(palette_path)
+    assert palette == [(255, 0, 0), (0, 255, 0)]
+
+
+def test_strict_quantization_stays_in_palette() -> None:
+    rgba = make_emblem(8, 8)
+    palette = [(255, 0, 0), (0, 255, 0), (255, 255, 255)]
+    result = quantize_rgba(rgba, mode="strict", palette=palette)
+    assert result is not None
+    unique = {
+        tuple((pixel[:3] * 255.0).round().astype(int))
+        for pixel in result.rgba.reshape(-1, 4)
+        if pixel[3] > 0.05
+    }
+    assert unique.issubset(set(palette))

tests/test_pipeline.py

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+from __future__ import annotations
+
+from pathlib import Path
+
+from repixelizer.baselines import naive_resize_baseline
+from repixelizer.metrics import coherence_breakdown
+from repixelizer.pipeline import run_pipeline
+from repixelizer.synthetic import fake_pixelize, make_emblem, make_sprite
+
+
+def test_pipeline_writes_output_and_diagnostics(tmp_path: Path) -> None:
+    source = make_emblem(32, 32)
+    fake = fake_pixelize(source, upscale=10, phase_x=0.15, phase_y=0.25, blur_radius=0.5)
+    input_path = tmp_path / "input.png"
+    output_path = tmp_path / "output.png"
+    diagnostics_dir = tmp_path / "diagnostics"
+
+    from repixelizer.io import save_rgba
+
+    save_rgba(input_path, fake)
+    result = run_pipeline(input_path, output_path, diagnostics_dir=diagnostics_dir, steps=24)
+    assert output_path.exists()
+    assert (diagnostics_dir / "run.json").exists()
+    assert result.output_rgba.shape[0] == result.inference.target_height
+    assert result.output_rgba.shape[1] == result.inference.target_width
+
+
+def test_pipeline_beats_naive_on_coherence_for_synthetic_emblem(tmp_path: Path) -> None:
+    source = make_emblem(32, 32)
+    fake = fake_pixelize(source, upscale=12, phase_x=0.2, phase_y=0.35, blur_radius=0.65)
+    input_path = tmp_path / "input.png"
+    output_path = tmp_path / "output.png"
+
+    from repixelizer.io import save_rgba
+
+    save_rgba(input_path, fake)
+    result = run_pipeline(input_path, output_path, steps=32)
+    naive = naive_resize_baseline(fake, width=result.inference.target_width, height=result.inference.target_height)
+    optimized_score = coherence_breakdown(result.output_rgba)["coherence_score"]
+    naive_score = coherence_breakdown(naive)["coherence_score"]
+    assert optimized_score >= naive_score
+
+
+def test_pipeline_preserves_transparency_for_sprite(tmp_path: Path) -> None:
+    source = make_sprite(24, 24)
+    fake = fake_pixelize(source, upscale=9, phase_x=0.1, phase_y=0.22, blur_radius=0.45)
+    input_path = tmp_path / "input.png"
+    output_path = tmp_path / "output.png"
+
+    from repixelizer.io import save_rgba
+
+    save_rgba(input_path, fake)
+    result = run_pipeline(input_path, output_path, steps=20)
+    alpha = result.output_rgba[..., 3]
+    assert alpha.min() < 0.05
+    assert alpha.max() > 0.9