Reputation: 43

I don't understand how this unit test is failing

Here is part of the unit test:

from nose.tools import *
from testing import *


def test_directions():
        assert_equal(scan("north"), [('direction', 'north')])
        result = scan("north south east")
        assert_equal(result, [('direction', 'north'), ('direction', 'south'), ('direction', 'east')])

And here is my code:

import string

def convert_number(s):
    try: 
        return int(s)
    except ValueError:
        return None

def scan(s):

    direction_words= ("north", "south", "east", "west", "down", "up", "left", "right", "back", "forwards", "backwards")
    verbs= ("go", "stop", "kill", "eat", "shoot", "run", "hide", "dodge")
    stop_words= ("the", "in", "of", "from", "at", "it")
    nouns= ("door", "bear", "princess", "cabinet", "gold", "money", "chest", "gun", "sword")        
    numbers= s.split()
    i=0
    j=0
    g=0
    m=0
    a=0
    b=0

    while a < len(numbers):
        if  type(convert_number(numbers[a])) == int:
            print [('number', int(numbers[a]) )]
            a += 1
        else:
            a += 1


    while i < len(direction_words):
        if direction_words[i] in s.split():
            s= string.lower(s)
            print [('direction', direction_words[i] ) ]
            i+=1 
        else:
            i+=1                

    while j < len(verbs):
        if verbs[j] in s.split():
            s= string.lower(s)
            print [('verb', verbs[j] )]
            j+=1
        else:
            j+=1    

    while g < len(stop_words):
        if stop_words[g] in s.split():
            s= string.lower(s)
            print [('stop', stop_words[g] )]
            g+=1
        else:
            g+=1

    while m < len(nouns):
        if nouns[m] in s.split():
            s= string.lower(s)
            print [('noun', nouns[m] )] 
            m+=1

        else:
            m+=1            

    while b< len(s.split()):      
        if numbers[b] not in nouns:
            if numbers[b] not in stop_words:
                if numbers[b] not in verbs:
                    if numbers[b] not in direction_words:
                        if  type(convert_number(numbers[b])) != int:   
                            print [('error', numbers[b] )]
                            b += 1

                        else:
                            b+=1    
                    else: b+=1
                else: b+=1
            else: b+=1
        else: b+=1


    else:
        return

When I run the unit tests here is what I get:

F
======================================================================
FAIL: tests.ex48_tests.test_directions
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/Users/Adam/Desktop/projects/ex48/tests/ex48_tests.py", line 6, in test_directions
    assert_equal(scan("north"), [('direction', 'north')])
AssertionError: None != [('direction', 'north')]
-------------------- >> begin captured stdout << ---------------------
[('direction', 'north')]

--------------------- >> end captured stdout << ----------------------

----------------------------------------------------------------------
Ran 1 test in 0.015s

FAILED (failures=1)

I don't understand how the test is failing. When I run the program in terminal it produces the exact same result as what is in the unit tests. I don't understand why it isn't passing.

Upvotes: 0

Answers (4)

John Gaines Jr.

Reputation: 11534

The function scan() returns None. So the assertation:

assert_equal(scan("north"), [('direction', 'north')])

is correctly failing.

Upvotes: 1

David Wolever

Reputation: 154494

Because your function is printing the result instead of returning it:

while i < len(direction_words):
    if direction_words[i] in s.split():
        s= string.lower(s)
        print [('direction', direction_words[i] ) ] # <--- HERE
        i+=1

I haven't read through all of LPTHW yet, so I can't tell you exactly what the best way to fix this code in the context of the book is… But if I were writing it, I would return a list, like this:

def scan(s):
    result = []
    ...

    while i < len(direction_words):
        if direction_words[i] in s.split():
            s= string.lower(s)
            # change the `print` statements to `result += …`
            result += [('direction', direction_words[i] ) ]
            i+=1 

    ...
    return result

Upvotes: 4