Writing Tests for Core

Where tests belong

If it’s a regression, it belongs in trac/tests/functional/testcases.py for now. Module-specific tests generally already have a trac/$MOD/tests/functional.py which you can add to. The environment is brought up as few times as possible, for speed, and your test order is guaranteed to be run in the order it’s added to the suite, at the end of the file.

Using Twill

The definitive guide for Twill commands is the Command Reference, but 90% of what you need is contained by convenience methods in FunctionalTester.go_to_*()and the following few commands:

tc.find:

Looks for a regex on the current page. If it isn’t found, raise an exception.

Example:

tc.find("\bPreferences\b")

tc.notfind:

Like find, but raises an exception if it is there.

Example:

tc.find(r"\bPreferences\b")

tc.follow:

Find a link matching the regex, and simulate clicking it.

Example:

tc.follow("Login")

tc.fv:

Short for formvalue, fill in a field.

Example:

tc.fv("searchform", "q", "ponies")

tc.submit:

Submit the active form.

Example:

tc.submit()

Example

This is how you might construct a test that verifies that admin users can see detailed version information.

Start with the navigation. You shouldn’t rely on the browser being in any specific state, so begin with FunctionalTester.go_to_*().

def test_about_page(self):
    self._tester.logout()       # Begin by logging out.
    self._tester.go_to_front()  # The homepage has a link we want
    tc.follow("About")          # Follow the link with "About" in it

    tc.find("Trac is a web-based software")
    tc.notfind("Version Info")

    self._tester.login("admin")
    self._tester.go_to_front()
    tc.follow("About")

    tc.find("Trac is a web-based software")
    tc.find("Version Info")