import unittest
import libxml2
from urlparse import urljoin

class TestText(unittest.TestCase):
  base = "http://example.com/blog/index.atom"

  def parse(self, feed, base=base):
    doc = libxml2.parseDoc(feed)
    doc.setBase(base)
    ctxt = doc.xpathNewContext()
    ctxt.xpathRegisterNs("atom","http://www.w3.org/2005/Atom")
    node = ctxt.xpathEval("//atom:link")[0]
    result = urljoin(node.getBase(doc), node.prop("href"))
    doc.freeDoc()
    return result 

  def test_no_xml_base_abs(self):
    assert "http://example.org/archives/2005/08/123.html" == self.parse("""
      <feed xmlns="http://www.w3.org/2005/Atom">
        <entry>
          <link href="http://example.org/archives/2005/08/123.html"/>
        </entry>
      </feed>
    """)

  def test_no_xml_base_rel(self):
    assert "http://example.com/archives/2005/08/123.html" == self.parse("""
      <feed xmlns="http://www.w3.org/2005/Atom">
        <entry>
          <link href="/archives/2005/08/123.html"/>
        </entry>
      </feed>
    """)

  def test_xml_base_on_feed_and_entry(self):
    assert "http://example.com/archives/2005/08/123.html" == self.parse("""
      <feed xmlns="http://www.w3.org/2005/Atom" xml:base="/archives/">
        <entry xml:base="2005/08/">
          <link href="123.html"/>
        </entry>
      </feed>
    """)

  def test_xml_base_overridden_on_link(self):
    assert "http://example.com/123.html" == self.parse("""
      <feed xmlns="http://www.w3.org/2005/Atom" xml:base="/archives/">
        <entry xml:base="2005/08/">
          <link href="123.html" xml:base="http://example.com/"/>
        </entry>
      </feed>
    """)

if __name__ == "__main__":
  unittest.main()