import numpy as np
from leonida.tiles import assemble

def fake_tile(row: int, col: int) -> np.ndarray:
    # Jede Kachel einfarbig, Farbe kodiert Zeile und Spalte.
    return np.full((256, 256, 3), (row, col, 7), dtype=np.uint8)

def test_assemble_crops_to_slice():
    mosaic = assemble(fake_tile)
    assert mosaic.shape == (3000, 3000, 3)
    # Nordwest-Ecke stammt aus Kachel (54, 60)
    assert tuple(mosaic[0, 0]) == (54, 60, 7)
    # Südost-Ecke stammt aus Kachel (65, 71)
    assert tuple(mosaic[-1, -1]) == (65, 71, 7)