When filing a distribution bug, an error is raised if you enter a
package name that doesn't exist in the distribution.

(XXX, Brad Bollenbach, 2006-05-05: This extra browser.open call
works around a bug where an exception will be raised if this extra
.open is removed! BjornT's looking into it.)

    >>> browser.open("http://localhost:9000/products/firefox/+bug/4")

    >>> browser.addHeader("Authorization", "Basic foo.bar@canonical.com:test")
    >>> browser.open("http://localhost:9000/distros/ubuntu/+filebug")

    >>> browser.getControl(name="field.title").value = "test"
    >>> browser.getControl(name="field.comment").value = "test"
    >>> browser.getControl(name="packagename_option").value = ["choose"]
    >>> browser.getControl(name="field.packagename").value = "foobar"

    >>> browser.getControl("Submit Bug Report").click()

    >>> '"foobar" does not exist in Ubuntu' in browser.contents
    True

An error is also raised if you choose the radio button to enter a
package name, but don't specify a package.

(XXX: Same hack as above.)

    >>> browser.open("http://localhost:9000/products/firefox/+bug/4")

    >>> browser.open("http://localhost:9000/distros/ubuntu/+filebug")

    >>> browser.getControl(name="field.title").value = "test"
    >>> browser.getControl(name="field.comment").value = "test"
    >>> browser.getControl(name="packagename_option").value = ["choose"]

    >>> browser.getControl("Submit Bug Report").click()

    >>> 'Please enter a package name' in browser.contents
    True