pytest测试range内置函数

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import pytest# ------------------------------
# 一、基础操作：正序序列测试用例
# ------------------------------
@pytest.mark.parametrize("start, end, step, expected",[# 默认步长（step=1）(None, 5, 1, [0, 1, 2, 3, 4]),  # 省略start，从0开始(1, 6, 1, [1, 2, 3, 4, 5]),     # 明确start和end# 列表索引对齐(0, len(["a", "b", "c"]), 1, [0, 1, 2]),  # 匹配列表长度的索引# 自定义正步长（间隔生成）(0, 10, 2, [0, 2, 4, 6, 8]),    # 步长2：偶数序列(3, 15, 3, [3, 6, 9, 12]),      # 步长3：3的倍数序列(1, 20, 5, [1, 6, 11, 16]),     # 步长5：间隔5递增],
)
def test_range_forward(start, end, step, expected):"""测试正序序列生成（start ≤ end，step为正）"""# 处理省略start的情况（range默认start=0）if start is None:result = list(range(end))else:result = list(range(start, end, step))assert result == expected# ------------------------------
# 二、进阶操作：倒序序列测试用例
# ------------------------------
@pytest.mark.parametrize("start, end, step, expected",[# 基础倒序（step=-1）(10, 0, -1, list(range(10, 0, -1))),  # 10→1：完整倒序(5, -1, -1, [5, 4, 3, 2, 1, 0]),     # 5→0：包含0# 自定义倒序步长（间隔递减）(10, -1, -2, [10, 8, 6, 4, 2, 0]),   # 步长-2：偶数倒序(15, 2, -3, [15, 12, 9, 6, 3]),      # 步长-3：3的倍数倒序(7, 0, -4, [7, 3]),                  # 步长-4：大幅递减],
)
def test_range_backward(start, end, step, expected):"""测试倒序序列生成（start > end，step为负）"""result = list(range(start, end, step))assert result == expected# ------------------------------
# 三、边界场景：特殊序列测试用例
# ------------------------------
@pytest.mark.parametrize("start, end, step, expected",[# 空序列场景(3, 1, 1, []),    # 正序但start>end(1, 3, -1, []),   # 倒序但start<end(5, 5, 1, []),    # start=end（左闭右开，无元素）(0, 0, -1, []),   # 倒序时start=end# 单元素序列(5, 6, 1, [5]),   # 正序：end=start+step(8, 7, -1, [8]),  # 倒序：end=start+step# 对齐固定长度（指定元素个数）(0, 10, 2, [0, 2, 4, 6, 8]),      # 5个元素（正序）(12, 0, -3, [12, 9, 6, 3]),       # 4个元素（倒序）],
)
def test_range_boundary(start, end, step, expected):"""测试边界场景：空序列、单元素序列、固定长度序列"""result = list(range(start, end, step))assert result == expected# ------------------------------
# 四、实用场景：结合其他函数测试用例
# ------------------------------
def test_range_with_map():"""测试range结合map生成规律列表（平方序列）"""result = list(map(lambda x: x*x, range(1, 11)))expected = [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]assert result == expecteddef test_range_with_filter():"""测试range结合filter生成筛选列表（偶数序列）"""result = list(filter(lambda x: x%2 == 0, range(10)))expected = [0, 2, 4, 6, 8]assert result == expecteddef test_range_reverse_traverse():"""测试range用于反向遍历（列表/字符串）"""# 反向遍历列表lst = ["a", "b", "c", "d"]reverse_lst = [lst[i] for i in range(len(lst)-1, -1, -1)]assert reverse_lst == ["d", "c", "b", "a"]# 反向遍历字符串s = "hello"reverse_s = "".join([s[i] for i in range(len(s)-1, -1, -1)])assert reverse_s == "olleh"def test_range_matrix_index():"""测试range生成多维度矩阵索引"""# 生成2行3列的索引对indices = []for i in range(2):for j in range(3):indices.append((i, j))expected = [(0,0), (0,1), (0,2), (1,0), (1,1), (1,2)]assert indices == expected# ------------------------------
# 五、局限性测试（验证不支持的场景）
# ------------------------------
def test_range_float_error():"""测试range不支持浮点数参数（应抛出TypeError）"""with pytest.raises(TypeError):range(0.1, 1.0, 0.2)  # 浮点数start/end/step不合法def test_range_zero_step_error():"""测试range步长为0（应抛出ValueError）"""with pytest.raises(ValueError):range(1, 5, 0)  # step=0不允许