Can a MagicMock object be iterated over?

What I would like to do is this...

x = MagicMock()
x.iter_values = [1, 2, 3]

for i in x:
    i.method()

I am trying to write a unit test for this function but I am unsure about how to go about mocking all of the methods called without calling some external resource...

def wiktionary_lookup(self):
    """Looks up the word in wiktionary with urllib2, only to be used for inputting data"""
    wiktionary_page = urllib2.urlopen(
        "http://%s.wiktionary.org/wiki/%s" % (self.language.wiktionary_prefix, self.name))
    wiktionary_page = fromstring(wiktionary_page.read())
    definitions = wiktionary_page.xpath("//h3/following-sibling::ol/li")
    print definitions.text_content()
    defs_list = []
    for i in definitions:
        print i
        i = i.text_content()
        i = i.split('\n')
        for j in i:
            # Takes out an annoying "[quotations]" in the end of the string, sometimes.
            j = re.sub(ur'\u2003\[quotations \u25bc\]', '', j)
            if len(j) > 0:
                defs_list.append(j)
    return defs_list

EDIT:

I may be misusing mocks, I am not sure. I am trying to unit-test this wiktionary_lookup method without calling external services...so I mock urlopen..I mock fromstring.xpath() but as far as I can see I need to also iterate through the return value of xpath() and call a method "text_contents()" so that is what I am trying to do here.

If I have totally misunderstood how to unittest this method then please tell me where I have gone wrong...

EDIT (adding current unittest code)

@patch("lang_api.models.urllib2.urlopen")
@patch("lang_api.models.fromstring")
def test_wiktionary_lookup_2(self, fromstring, urlopen):
    """Looking up a real word in wiktionary, should return a list"""
    fromstring().xpath.return_value = MagicMock(
        content=["test", "test"], return_value='test\ntest2')
    # A real word should give an output of definitions
    output = self.things.model['word'].wiktionary_lookup()
    self.assertEqual(len(output), 2)

Solution

What you actually want to do is not return a Mock with a return_value=[]. You actually want to return a list of Mock objects. Here is a snippet of your test code with the correct components and a small example to show how to test one of the iterations in your loop:

@patch('d.fromstring')
@patch('d.urlopen')
def test_wiktionary(self, urlopen_mock, fromstring_mock):
    urlopen_mock.return_value = Mock()
    urlopen_mock.return_value.read.return_value = "some_string_of_stuff"

    mocked_xpath_results = [Mock()]
    fromstring_mock.return_value.xpath.return_value = mocked_xpath_results

    mocked_xpath_results[0].text_content.return_value = "some string"

So, to dissect the above code to explain what was done to correct your problem:

The first thing to help us with testing the code in the for loop is to create a list of mock objects per:

mocked_xpath_results = [Mock()]

Then, as you can see from

fromstring_mock.return_value.xpath.return_value = mocked_xpath_results

We are setting the return_value of the xpath call to our list of mocks per mocked_xpath_results.

As an example of how to do things inside your list, I added how to mock within the loop, which is shown with:

mocked_xpath_results[0].text_content.return_value = "some string"

In unittests (this might be a matter of opinion) I like to be explicit, so I'm accessing the list item explicitly and determining what should happen.

Hope this helps.