写一段程序，删除字符串a中包含的字符串b，举例 输入a = "asdw",b = "sd" 返回 字符串 “aw”，并且测试这个程序。

Answer 1

def delBString(a,b):
    if not isinstance(a,str):
        raise TypeError("a is not str")
    if not isinstance(b,str):
        raise TypeError("b is not str")
    if len(a) < len(b):
        raise Exception('a length must large to b length')
    result = []
    flag = False
    i=0
    la = len(a)
    lb = len(b)
    while i <la:
        j = 0
        while j < lb:
            if i+j < la and a[i+j] == b[j]:
                j += 1
            else :
                j += 1
                flag = False
                break
            flag = True
        if flag:
            i += lb
        else:
            result.append(a[i])
            i += 1
    return "".join(result)

 

测试用例：
class TestdelInnerStringFunctions():
    def setUp(self):
        pass
    def tearDown(self):
        pass
    def test_nomorl1(self):
        assert delBString('asdqwe','we') == 'asdq'
    def test_nomorl2(self):
        assert delBString('asdqwe','0') == 'asdqwe'
    def test_nomorl3(self):
        assert delBString('测试asdqwe','we') == '测试asdq'
    def test_nomorl4(self):
        assert delBString('测试asdqwe','测试') == 'asdqwe'
    def test_nomorl5(self):
        assert delBString('asdqwe','') == 'asdqwe'
    def test_nomorl6(self):
        with pytest.raises(TypeError):
            delBString('', 0)
    def test_nomorl7(self):
        with pytest.raises(TypeError):
            delBString(0, 'as')
    def test_nomorl8(self):
        with pytest.raises(TypeError):
            delBString(True)
    def test_nomorl9(self):
       with pytest.raises(Exception) as excinfo:
           delBString('acd','acde')
       assert "a length must large to b length" in str(excinfo.value)
       assert excinfo.type == Exception