"""
测试字典工具。
无外部依赖，可离线运行。
"""

from paste.util import udict


class TestUdict:
    """字典工具测试"""

    def test_get_by_path_simple(self):
        """简单路径读取"""
        data = {"a": 1, "b": 2}
        assert udict.get_by_path(data, "a") == 1

    def test_get_by_path_nested(self):
        """嵌套路径读取"""
        data = {"a": {"b": {"c": 123}}}
        assert udict.get_by_path(data, "a.b.c") == 123

    def test_get_by_path_missing(self):
        """缺失路径处理"""
        data = {"a": 1}
        assert udict.get_by_path(data, "b.c.d", "default") == "default"

    def test_get_by_path_none_default(self):
        """缺失路径无默认值"""
        data = {"a": 1}
        assert udict.get_by_path(data, "b") is None

    def test_get_with_default_existing(self):
        """存在的键读取"""
        data = {"key": "value"}
        assert udict.get_with_default(data, "key", "fallback") == "value"

    def test_get_with_default_missing(self):
        """缺失键使用默认值"""
        data = {"key": "value"}
        assert udict.get_with_default(data, "missing", "fallback") == "fallback"

    def test_get_with_default_none_value(self):
        """值为 None 时使用默认值"""
        data = {"key": None}
        assert udict.get_with_default(data, "key", "fallback") == "fallback"