The utf8ToUnicodeEntities function doesn't exist (wrong code version?)

In the previous version it was:
$success = @$doc->loadXML($string);
That works!

Rather than fixing the behavior, I would suggest to add a new RDF class, as proposed in the description of this issue.
RSS 1.0 is completely an other branch compared with RSS 2.0.

The main difference between RSS 0.91 branch (created by Dave Winer) and RSS 1.0 branch (managed by RSS-DEV Working Group) is that the latter is RDF based while RDF architecture has been completely removed in RSS 0.91, RSS 0.92, RSS 2.0.

Additionally, I would suggest to add a new class property to return feed type/version.
The following seems to be a list of formats currently supported by Zend feed:

• Atom 0.3
• Atom 0.5
• Atom 1.0
• RSS 0.91
• RSS 0.92
• RSS 2.0
  The following formats should be supported but they are not, right now:
• RSS 1.0
  Perhaps a new ticket is the better solution for a new proposal, rather than a comment.

The following line doesn't really makes sense to me.

$this->assertTrue($feed->count() > 0);

_importRssValid method is an utility method and we cannot assume in advance the file he's going to fetch is not a valid empty feed.
I would create some valid RSS 1.0 unit tests instead.

The other part of the patch, the code fragment that should introduce RSS 1.0 compatibility it's fine, but I think it's incomplete.
Zend_Feed doesn't handle only feed import but it's able to create and edit a feed as well.

Did you think about how an imported RSS 1.0 feed will be printed out?
I assume it would be handled by Zend_Feed_Rss class but this library, as underlined by ZF-44, always returns an RSS 2.0 instance.
It means, an RSS 1.0 come in and an RSS 2.0 come out... I suppose this is not a good workflow.

What do you propose to fix this consequential issue?

For the sake of completeness, I'd like to share an additional though.
http://www.feedparser.org/ is, so far, the best feed parser written in python and probably one of the best feed parsers in the world.
Zend_Feed should probably learn something from this library!

Please raise your voice Matthew if this a no go by me

In terms of the portion that patches tests, it may be a better design decision to create an additional supporting method that first calls _importRssValid and then applies a non-empty check, and have all tests with non-empty test data files call that instead of _importRssValid, so that cases where data is expected to be empty can continue to function as normal.

Thoughts anyone?

I've applied my patch to Zend_Feed_Rss in a current SVN checkout to confirm that it still works. If I run the modified unit tests on the unpatched version of this class file, I get this output:

$ phpunit Zend_Feed_ImportTest tests/Zend/Feed/ImportTest.php 
PHPUnit 3.3.8 by Sebastian Bergmann.

..............FF..........

Time: 3 seconds

There were 2 failures:

1) testRss100Sample1(Zend_Feed_ImportTest)
Failed asserting that <integer:2> matches expected value <integer:0>.

2) testRss100Sample2(Zend_Feed_ImportTest)
Failed asserting that <integer:1> matches expected value <integer:0>.

FAILURES!
Tests: 26, Assertions: 30, Failures: 2.

If I apply the patch and run the modified unit tests again, I get this output:

$ phpunit Zend_Feed_ImportTest tests/Zend/Feed/ImportTest.php 
PHPUnit 3.3.8 by Sebastian Bergmann.

..........................

Time: 2 seconds

OK (26 tests, 30 assertions)

Is this an acceptable solution?

http://ranking.goo.ne.jp/rss/keyword/keyrank_all1/index.rdf

The source of that feed begins with
<?xml version="1.0" encoding="utf-8" ?>
<?xml-stylesheet href="/rss/user.xsl" type="text/xsl" media="screen" ?>
<rdf:RDF xmlns="http://purl.org/rss/1.0/"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xml:lang="ja">
<channel rdf:about="http://ranking.goo.ne.jp/service/001/">

Zend_Feed_Rss#__wakeup() checks if the feed is rdf or not with the following code
but the firstChild of that feed is "xml-stylesheet" and so it is not treated as rdf.
Please improve the check routine.
if ($this->_element->firstChild->nodeName == 'rdf:RDF') { $this->_element = $this->_element->firstChild; } else { $this->_element = $this->_element->getElementsByTagName('channel')->item(0); }

Quick fix for the client user:
Replace
$feed = Zend_Feed::import($url);
with something like
$string = file_get_contents($url);
$string = str_replace('<?xml-stylesheet href="/rss/user.xsl" type="text/xsl" media="screen" ?>', '', $string); // or whatever between <?xml ?> and <rdf:RDF
$feed = Zend_Feed::importString($string);