def _default_fuser(dst: np.ndarray, src: np.ndarray, dst_nodata) -> None:
""" Overwrite only those pixels in `dst` with `src` that are "not valid"
For every pixel in dst that equals to dst_nodata replace it with pixel
from src.
"""
np.copyto(dst, src, where=invalid_mask(dst, dst_nodata))
def test_valid_mask():
xx = np.zeros((4, 8), dtype='float32')
mm = valid_mask(xx, 0)
assert mm.dtype == 'bool'
assert mm.shape == xx.shape
assert not mm.all()
assert not mm.any()
nn = invalid_mask(xx, 0)
assert nn.dtype == 'bool'
assert nn.shape == xx.shape
assert nn.all()
assert nn.any()
mm = valid_mask(xx, 13)
assert mm.dtype == 'bool'
assert mm.shape == xx.shape
assert mm.all()
nn = invalid_mask(xx, 13)
assert nn.dtype == 'bool'
assert nn.shape == xx.shape
assert not nn.any()
mm = valid_mask(xx, None)
assert mm.dtype == 'bool'
assert mm.shape == xx.shape
assert mm.all()
nn = invalid_mask(xx, None)
assert nn.dtype == 'bool'
assert nn.shape == xx.shape
assert not nn.any()
mm = valid_mask(xx, np.nan)
assert mm.dtype == 'bool'
assert mm.shape == xx.shape
assert mm.all()
nn = invalid_mask(xx, np.nan)
assert nn.dtype == 'bool'
assert nn.shape == xx.shape
assert not nn.any()
xx[0, 0] = np.nan
mm = valid_mask(xx, np.nan)
assert not mm[0, 0]
assert mm.sum() == (4 * 8 - 1)
nn = invalid_mask(xx, np.nan)
assert nn[0, 0]
assert nn.sum() == 1