Pillow/Tests/test_file_gribstub.py

import pytest
from PIL import GribStubImagePlugin, Image

from .helper import hopper

TEST_FILE = "Tests/images/WAlaska.wind.7days.grb"


def test_open():
    # Act
    with Image.open(TEST_FILE) as im:

        # Assert
        assert im.format == "GRIB"

        # Dummy data from the stub
        assert im.mode == "F"
        assert im.size == (1, 1)


def test_invalid_file():
    # Arrange
    invalid_file = "Tests/images/flower.jpg"

    # Act / Assert
    with pytest.raises(SyntaxError):
        GribStubImagePlugin.GribStubImageFile(invalid_file)


def test_load():
    # Arrange
    with Image.open(TEST_FILE) as im:

        # Act / Assert: stub cannot load without an implemented handler
        with pytest.raises(OSError):
            im.load()


def test_save(tmp_path):
    # Arrange
    im = hopper()
    tmpfile = str(tmp_path / "temp.grib")

    # Act / Assert: stub cannot save without an implemented handler
    with pytest.raises(OSError):
        im.save(tmpfile)