Python-如何使用其他函数创建测试函数？

Question

I'm having a hard time trying to use another function into a function that tests the function I added with print statements. For example with this function that reverses a string. I want to use print statements in another function that tests the reverse function, but I'm having a hard time understand how I can incorporate the is_reverse function into the testing function without adding parameters into the testing function.

def is_reverse( st1, st2 ):
    if len( st1 ) != len( st2 ):
        return False
    i = 0
    j = len( st2 ) - 1
    while j > 0:
        if st1[i] != st2[j]:
            return False
        i += 1
        j -= 1
    return True

def test_is_reverse( ):
    print( "is_reverse( \"hey\", \"yah\" ) == False.\"" )
    print( "is_reverse( \"man\", \"nam\" ) == True.\"" )

Answer 1

One way to do it is to pass the function that you want to use to print the error messages as an argument to the test function.

Something along the lines of:

def my_print_func (errmsg):
    print (errmsg)

def test_is_reverse(f ):
    f( "is_reverse( \"hey\", \"yah\" ) == False.\"" )
    f( "is_reverse( \"man\", \"nam\" ) == True.\"" )

To test, you do:

 test_is_reverse(my_print_func)

That said, you should avoid reinventing the wheel and use Python unittest framework, see https://docs.python.org/2/library/unittest.html

Answer 2

You can setup a function to run your tests and print the results:

def test_is_reverse(st1, st2):
    # Define tests here, for example:
    print st1, st2, is_reverse(st1,st2), is_reverse(st2, st1)
    print is_reverse(st1,st1) == is_reverse(sty, st1)