Improve serializer test coverage

Should be 100% coverage now. The ProcessingInstruction needed to be
imported directly from ElementTree as PY27 was using a PIProxy which
resulted in a  bug. Interestingly, PY3 worked fine.

Also removed the encoding code as it was not used. Besides it was only
ever accessable from a private function.

2 files changed, 67 insertions, 20 deletions

diff --git a/markdown/serializers.py b/markdown/serializers.py
index 63446b9..187d755 100644
--- a/markdown/serializers.py
+++ b/markdown/serializers.py
@@ -39,6 +39,7 @@
 
 from __future__ import absolute_import
 from __future__ import unicode_literals
+from xml.etree.ElementTree import ProcessingInstruction
 from . import util
 ElementTree = util.etree.ElementTree
 QName = util.etree.QName
@@ -46,8 +47,6 @@ if hasattr(util.etree, 'test_comment'):  # pragma: no cover
     Comment = util.etree.test_comment
 else:  # pragma: no cover
     Comment = util.etree.Comment
-PI = util.etree.PI
-ProcessingInstruction = util.etree.ProcessingInstruction
 
 __all__ = ['to_html_string', 'to_xhtml_string']
 
@@ -66,13 +65,6 @@ def _raise_serialization_error(text):  # pragma: no cover
         )
 
 
-def _encode(text, encoding):
-    try:
-        return text.encode(encoding, "xmlcharrefreplace")
-    except (TypeError, AttributeError):  # pragma: no cover
-        _raise_serialization_error(text)
-
-
 def _escape_cdata(text):
     # escape character data
     try:
@@ -181,15 +173,12 @@ def _serialize_html(write, elem, format):
         write(_escape_cdata(elem.tail))
 
 
-def _write_html(root, encoding=None, format="html"):
+def _write_html(root, format="html"):
     assert root is not None
     data = []
     write = data.append
     _serialize_html(write, root, format)
-    if encoding is None:
-        return "".join(data)
-    else:
-        return _encode("".join(data), encoding)
+    return "".join(data)
 
 
 # --------------------------------------------------------------------
diff --git a/tests/test_apis.py b/tests/test_apis.py
index a627c79..2875c85 100644
--- a/tests/test_apis.py
+++ b/tests/test_apis.py
@@ -18,6 +18,7 @@ from logging import DEBUG, WARNING, CRITICAL
 import yaml
 import tempfile
 from io import BytesIO
+from xml.etree.ElementTree import ProcessingInstruction
 
 
 PY3 = sys.version_info[0] == 3
@@ -465,23 +466,47 @@ class testSerializers(unittest.TestCase):
     def testHtml(self):
         """ Test HTML serialization. """
         el = markdown.util.etree.Element('div')
+        el.set('id', 'foo<&">')
         p = markdown.util.etree.SubElement(el, 'p')
-        p.text = 'foo'
+        p.text = 'foo <&escaped>'
+        p.set('hidden', 'hidden')
         markdown.util.etree.SubElement(el, 'hr')
+        non_element = markdown.util.etree.SubElement(el, None)
+        non_element.text = 'non-element text'
+        script = markdown.util.etree.SubElement(non_element, 'script')
+        script.text = '<&"test\nescaping">'
+        el.tail = "tail text"
         self.assertEqual(
             markdown.serializers.to_html_string(el),
-            '<div><p>foo</p><hr></div>'
+            '<div id="foo&lt;&amp;&quot;&gt;">'
+            '<p hidden>foo &lt;&amp;escaped&gt;</p>'
+            '<hr>'
+            'non-element text'
+            '<script><&"test\nescaping"></script>'
+            '</div>tail text'
         )
 
     def testXhtml(self):
         """" Test XHTML serialization. """
         el = markdown.util.etree.Element('div')
+        el.set('id', 'foo<&">')
         p = markdown.util.etree.SubElement(el, 'p')
-        p.text = 'foo'
+        p.text = 'foo<&escaped>'
+        p.set('hidden', 'hidden')
         markdown.util.etree.SubElement(el, 'hr')
+        non_element = markdown.util.etree.SubElement(el, None)
+        non_element.text = 'non-element text'
+        script = markdown.util.etree.SubElement(non_element, 'script')
+        script.text = '<&"test\nescaping">'
+        el.tail = "tail text"
         self.assertEqual(
             markdown.serializers.to_xhtml_string(el),
-            '<div><p>foo</p><hr /></div>'
+            '<div id="foo&lt;&amp;&quot;&gt;">'
+            '<p hidden="hidden">foo&lt;&amp;escaped&gt;</p>'
+            '<hr />'
+            'non-element text'
+            '<script><&"test\nescaping"></script>'
+            '</div>tail text'
         )
 
     def testMixedCaseTags(self):
@@ -496,8 +521,17 @@ class testSerializers(unittest.TestCase):
             '<MixedCase>not valid <EMPHASIS>html</EMPHASIS><HR /></MixedCase>'
         )
 
-    def testQName(self):
-        """ Test serialization of QName. """
+    def testProsessingInstruction(self):
+        """ Test serialization of ProcessignInstruction. """
+        pi = ProcessingInstruction('foo', text='<&"test\nescaping">')
+        self.assertIs(pi.tag, ProcessingInstruction)
+        self.assertEqual(
+            markdown.serializers.to_xhtml_string(pi),
+            '<?foo &lt;&amp;"test\nescaping"&gt;?>'
+        )
+
+    def testQNameTag(self):
+        """ Test serialization of QName tag. """
         div = markdown.util.etree.Element('div')
         qname = markdown.util.etree.QName('http://www.w3.org/1998/Math/MathML', 'math')
         math = markdown.util.etree.SubElement(div, qname)
@@ -525,6 +559,30 @@ class testSerializers(unittest.TestCase):
             '</div>'
         )
 
+    def testQNameAttribute(self):
+        """ Test serialization of QName attribute. """
+        div = markdown.util.etree.Element('div')
+        div.set(markdown.util.etree.QName('foo'), markdown.util.etree.QName('bar'))
+        self.assertEqual(
+            markdown.serializers.to_xhtml_string(div),
+            '<div foo="bar"></div>'
+        )
+
+    def testBadQNameTag(self):
+        """ Test serialization of QName with no tag. """
+        qname = markdown.util.etree.QName('http://www.w3.org/1998/Math/MathML')
+        el = markdown.util.etree.Element(qname)
+        self.assertRaises(ValueError, markdown.serializers.to_xhtml_string, el)
+
+    def testQNameEscaping(self):
+        """ Test QName escaping. """
+        qname = markdown.util.etree.QName('<&"test\nescaping">', 'div')
+        el = markdown.util.etree.Element(qname)
+        self.assertEqual(
+            markdown.serializers.to_xhtml_string(el),
+            '<div xmlns="&lt;&amp;&quot;test&#10;escaping&quot;&gt;"></div>'
+        )
+
     def buildExtension(self):
         """ Build an extension which registers fakeSerializer. """
         def fakeSerializer(elem):