IPOMsgSet objects have IProductSeries or ISourcePackage as its direct
structural object.

Taking an IPOMsgSet for IProductSeries context:

  >>> browser.open(
  ...     'http://translations.launchpad.dev/evolution/trunk/+pots/'
  ...     'evolution-2.2/es/1')

We get a +translate page because that's the only page for an IPOMsgSet and the
system forwards automatically there.

  >>> print browser.url
  http://translations.launchpad.dev/evolution/trunk/+pots/evolution-2.2/es/1/+translate

The Application tabs should point to IProductSeries URLs.

    >>> print_location_apps(browser.contents)
    * Overview - http://launchpad.dev/evolution/trunk
    * Code - http://code.launchpad.dev/evolution
    * Bugs - http://bugs.launchpad.dev/evolution/trunk
    * Blueprints - http://blueprints.launchpad.dev/evolution/trunk
    * Translations (selected) - http://translations.launchpad.dev/evolution/trunk
    * Answers - not linked

Taking an IPOMsgSet for ISourcePackage context:

  >>> browser.open(
  ...     'http://translations.launchpad.dev/ubuntu/hoary/+source/evolution/'
  ...     '+pots/evolution-2.2/es/1')

We get a +translate page because that's the only page for an IPOMsgSet and the
system forwards automatically there.

  >>> print browser.url
  http://translations.launchpad.dev/ubuntu/hoary/+source/evolution/+pots/evolution-2.2/es/1/+translate

The Application tabs should point to ISourcePackage URLs.

    >>> print_location_apps(browser.contents)
    * Overview - http://launchpad.dev/ubuntu/hoary/+source/evolution
    * Code - http://code.launchpad.dev/ubuntu/hoary/+source/evolution
    * Bugs - http://bugs.launchpad.dev/ubuntu/hoary/+source/evolution
    * Blueprints - not linked
    * Translations (selected) - http://translations.launchpad.dev/ubuntu/hoary/+source/evolution
    * Answers - not linked