Assertion helper for zope.testbrowser and unittest

zope.testbrowser is a valuable tool for integration tests. Historically,  the Zope community used to write quite a lot of doctests, but we at gocept have found them to be rather clumsy and too often yielding neither good tests nor good documentation. That’s why we don’t use doctest much anymore, and prefer plain unittest.TestCases instead. However, doctest has one very nice feature, ellipsis matching, that is really helpful for checking HTML output, since you can only make assertions about the parts that interest you. For example, given this kind of page:

>>> print browser.contents
<html>
  <head>
    <title>Simple Page</title>
  </head>
  <body>
    <h1>Simple Page</h1>
  </body>
</html>

If all you’re interested in is that the <h1> is rendered properly, you can simply say:

>>> print browser.contents
<...<h1>Simple Page</h1>...

We’ve now ported this functionality to unittest, as assertEllipsis, in gocept.testing. Some examples:

self.assertEllipsis('...bar...', 'foo bar qux')
# -> nothing happens

self.assertEllipsis('foo', 'bar')
# -> AssertionError: Differences (ndiff with -expected +actual):
     - foo
     + bar

self.assertNotEllipsis('foo', 'foo')
# -> AssertionError: "Value unexpectedly matches expression 'foo'."

To use it, inherit from gocept.testing.assertion.Ellipsis in addition to unittest.TestCase.

Author: Wolfgang Schnerring

Wolfgang is a software developer working at gocept.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s