Always do absolute imports. 'urls' could be anything.
You also need to have this below with the project imports.

Imports must always be alphabetical.

Name this repository_url_patterns.

The summary has to be one line without wrapping.

"thr" -> "the"

Trailing whitespace.

"URL" instead of "url"

The parameters to patterns need to align.
Spaces around the +

Trailing whitespace.

Alphabetical order.

This must be one import statement, using parens, and one per line to prevent going over the line limit.

Alphabetical.

Two blank lines.

This doesn't meet our formatting rules, and you're missing url(). It should be:
repository_url_patterns = patterns(
    '',

    url('^hooks/pre-commit/$', ...),
)


Also note the /$ that you need at the end.

Two blank lines.

This is kind of hard to read. Can you group it into logical sections, with comments about what you're testing in each case?

URLs should always have a trailing /.
Same below.

Two blank lines.

Two blank lines.

You should just include dynamic_urls, and not do a new patterns(...)

This looks like a merge failure.

Remove the trailing whitespace.
In fact, revert this file.

Merge failure. Revert this file.

Revert this file too.

Imports must always be alphabetical.

No blank line between these.

I don't really have much to add to Christian's review, but I'll do another review on your next update!

This can just be if cls.repo_urlpatterns.

If I do that I get the following error:
The included urlconf <DynamicURLResolver [] (None:None) > doesn't have any patterns in it

You don't need to create your own client. You can just use self.client.

This needs to be a patterns(...)

This should just be dummyView (which needs to be renamed to something more specific, and not use camelCase).

You're missing the trailing slashes on these URLs, which will prevent you from getting to the right view.

Isn't this already in alphabetical order ?
django...

djblets.....

Here are just some minor style issues (a lot of which are duplicates)!

Review Board imports should go after the third-party module (Django, Djblets, etc.) imports, separated by a blank line.

This should be in alphabetical order - include should be before patterns, and the line needs to be moved to being before from django.utils import six.

URL instead of url.

These should be in alphabetical order, before from django.utils.import six.

URL instead of url.

URL instead of url.

This should be formatted like this instead:
repository_url_patterns = patterns(
    '',
    url(r'^hooks/pre-commit/$', hosting_service_url_test_view)
)

Comments should start with a # and a single space, like:

# This is a comment.
Also, URL instead of url.

include should be before patterns.

Home stretch! A few things to fix up now that the bulk of this is done.

"URL pattern"
"class"

"KeyError"

The '' should go on the next line.
Spaces around the +

I'd suggest moving this code after the try block. It's best to keep the bodies of a try/except as simple as possible.

Docstring summaries cannot wrap unless they are a unit test function.
I'd actually recommend moving this into DummyService. You should be abe to make this a @classmethod.

Should be 2 blank lines.

This should be formatted like:
repository_url_patterns = patterns(
    '',

    url(r'.....', view_name),
)

"URL"
Same any time it appears in a comment or string.

Make sure you have this as the first line (with a blank line after):
from __future__ import unicode_literals

Blank line between these.

Space after '' in patterns()

Ship It!

I've tested this out with my GitHub hook, and it works! :) While doing this, I noticed a few more really minor things.

This import isn't used.

"URL"

The last parenthesis should be on the next line, aligned with cls_urlpatterns on line 363.

These lines are indented an extra level.

"registering"

This import isn't used.

There should be a space after the comma, not before (so it should be ...patterns('', dynamic_urls))

There is extra whitespace before the parenthesis.

There's a typo in your change description: "called ro access web hooks"

These lines are indented four too-many spaces.

Actually, this should just be removed entirely from the BitBucket hosting service, no?

Ship It!