test_imageuri_validator.py

import base64
import os
import pytest
from _plotly_utils.basevalidators import ImageUriValidator

from PIL import Image


# Fixtures
# --------
@pytest.fixture()
def validator():
    return ImageUriValidator("prop", "parent")


# Tests
# -----
# ### Acceptance ###
@pytest.mark.parametrize(
    "val",
    [
        "http://somewhere.com/images/image12.png",
        "data:image/png;base64,iVBORw0KGgoAAAANSU",
    ],
)
def test_validator_acceptance(val, validator):
    assert validator.validate_coerce(val) == val


# ### Coercion from PIL Image ###
def test_validator_coercion_PIL(validator):
    # Single pixel black png (http://png-pixel.com/)

    tests_dir = os.path.dirname(os.path.dirname(__file__))
    img_path = os.path.join(tests_dir, "resources", "1x1-black.png")

    with open(img_path, "rb") as f:
        hex_bytes = base64.b64encode(f.read()).decode("ascii")
        expected_uri = "data:image/png;base64," + hex_bytes

    img = Image.open(img_path)
    coerce_val = validator.validate_coerce(img)
    assert coerce_val == expected_uri


# ### Rejection ###
@pytest.mark.parametrize("val", [23, set(), []])
def test_rejection_by_type(val, validator):
    with pytest.raises(ValueError) as validation_failure:
        validator.validate_coerce(val)

    assert "Invalid value" in str(validation_failure.value)