"""Tests for get_default_image_format() — the IMAGE_STORAGE_FORMAT env var helper.

The contract: only 'png' and 'jpeg' are honoured, matching is case-insensitive,
and anything else (including an unset var) falls back to 'png'. Callers in
gpt_image_2, image_v2, and wp all rely on the fallback never returning an
unsupported format.
"""

from unittest.mock import patch

from app.services.image import get_default_image_format


class TestGetDefaultImageFormat:

    @patch.dict("os.environ", {"IMAGE_STORAGE_FORMAT": "jpeg"})
    def test_returns_jpeg_when_set(self):
        assert get_default_image_format() == "jpeg"

    @patch.dict("os.environ", {"IMAGE_STORAGE_FORMAT": "png"})
    def test_returns_png_when_set(self):
        assert get_default_image_format() == "png"

    @patch.dict("os.environ", {"IMAGE_STORAGE_FORMAT": "JPEG"})
    def test_case_insensitive(self):
        assert get_default_image_format() == "jpeg"

    @patch.dict("os.environ", {"IMAGE_STORAGE_FORMAT": "bmp"})
    def test_invalid_value_falls_back_to_png(self):
        assert get_default_image_format() == "png"

    @patch.dict("os.environ", {}, clear=True)
    def test_unset_falls_back_to_png(self):
        assert get_default_image_format() == "png"