Python unittest for testing contents of a folder

Question

I have a projects where I need to write a module containing a function to examine the contents of the current working directory and print out a count of how many files have each extension (".txt", ".doc", etc.)

Then I need to write a separate module to verify by testing that the function gives correct results.

import os
from collections import Counter

filenames = {}
extensions = []
file_counts = {}
extensions2 = {}

def examine(): 

    for filename in filenames:
        f = open(filename, "w")
        f.write("Some text\n")
        f.close()
        name, extension = filename.split('.')
        extensions.append(extension)

    extensions2 = dict(Counter(extensions))

    return extensions2

And this is the test:

import unittest
import tempfile
import os
import shutil
import examine_directory as examdir

class TestExamine(unittest.TestCase):
    def setUp(self):
        self.origdir = os.getcwd()
        self.dirname = tempfile.mkdtemp("testdir")
        os.chdir(self.dirname)

    examdir.filenames = {"this.txt", "that.txt", "the_other.txt","this.doc","that.doc","this.pdf","first.txt","that.pdf"}

def test_dirs(self):
    expected = {'pdf': 2, 'txt': 4, 'doc': 2}
    self.assertEqual(examdir.extensions2, expected, "Creation of files not possible")

def tearDown(self):
    os.chdir(self.origdir)
    shutil.rmtree(self.dirname) 

if __name__ == "__main__":
    unittest.main()

I'm stuck and I need some help. I'm getting an assertEqual error.

Thanks in advance.

Answer 1

You are getting the assertEqual error because examdir.extensions2 is not the same as expected , that should be your first clue. Try printing out the values of both before the assert call to verify this.

Second, I assume the first file you've listed here is called examine_directory ? Looking at that file, I see that extensions2 is initialized to an empty dictionary {} . The examine function returns the value of a local variable called extensions2 but:

1. It does not assign it to your global dictionary (I think that's the behaviour you're expecting)
2. examine() does not get called from your test script