test: Factored out normalization code into normalize.py.

1 files changed, 141 insertions, 0 deletions

diff --git a/test/normalize.py b/test/normalize.py
new file mode 100644
index 0000000..6cb11b4
--- /dev/null
+++ b/test/normalize.py
@@ -0,0 +1,141 @@
+from HTMLParser import HTMLParser, HTMLParseError
+from htmlentitydefs import name2codepoint
+import sys
+import re
+import cgi
+
+# Normalization code, adapted from
+# https://github.com/karlcow/markdown-testsuite/
+significant_attrs = ["alt", "href", "src", "title"]
+whitespace_re = re.compile('/s+/')
+class MyHTMLParser(HTMLParser):
+    def __init__(self):
+        HTMLParser.__init__(self)
+        self.last = "starttag"
+        self.in_pre = False
+        self.output = u""
+        self.last_tag = ""
+    def handle_data(self, data):
+        after_tag = self.last == "endtag" or self.last == "starttag"
+        after_block_tag = after_tag and self.is_block_tag(self.last_tag)
+        if after_tag and self.last_tag == "br":
+            data = data.lstrip('\n')
+        data = whitespace_re.sub(' ', data)
+        if after_block_tag and not self.in_pre:
+            if self.last == "starttag":
+                data = data.lstrip()
+            elif self.last == "endtag":
+                data = data.strip()
+        self.output += data
+        self.last = "data"
+    def handle_endtag(self, tag):
+        if tag == "pre":
+            self.in_pre = False
+        if self.is_block_tag(tag):
+            self.output = self.output.rstrip()
+        self.output += "</" + tag + ">"
+        self.last_tag = tag
+        self.last = "endtag"
+    def handle_starttag(self, tag, attrs):
+        if tag == "pre":
+            self.in_pre = True
+        self.output += "<" + tag
+        # For now we don't strip out 'extra' attributes, because of
+        # raw HTML test cases.
+        # attrs = filter(lambda attr: attr[0] in significant_attrs, attrs)
+        if attrs:
+            attrs.sort()
+            for (k,v) in attrs:
+                self.output += " " + k
+                if v != None:
+                    self.output += ("=" + '"' + cgi.escape(v,quote=True) + '"')
+        self.output += ">"
+        self.last_tag = tag
+        self.last = "starttag"
+    def handle_startendtag(self, tag, attrs):
+        """Ignore closing tag for self-closing """
+        self.handle_starttag(tag, attrs)
+        self.last_tag = tag
+        self.last = "endtag"
+    def handle_comment(self, data):
+        self.output += '<!--' + data + '-->'
+        self.last = "comment"
+    def handle_decl(self, data):
+        self.output += '<!' + data + '>'
+        self.last = "decl"
+    def unknown_decl(self, data):
+        self.output += '<!' + data + '>'
+        self.last = "decl"
+    def handle_pi(self,data):
+        self.output += '<?' + data + '>'
+        self.last = "pi"
+    def handle_entityref(self, name):
+        try:
+            c = unichr(name2codepoint[name])
+        except KeyError:
+            c = None
+        self.output_char(c, '&' + name + ';')
+        self.last = "ref"
+    def handle_charref(self, name):
+        try:
+            if name.startswith("x"):
+                c = unichr(int(name[1:], 16))
+            else:
+                c = unichr(int(name))
+        except ValueError:
+                c = None
+        self.output_char(c, '&' + name + ';')
+        self.last = "ref"
+    # Helpers.
+    def output_char(self, c, fallback):
+        if c == u'<':
+            self.output += "&lt;"
+        elif c == u'>':
+            self.output += "&gt;"
+        elif c == u'&':
+            self.output += "&amp;"
+        elif c == u'"':
+            self.output += "&quot;"
+        elif c == None:
+            self.output += fallback
+        else:
+            self.output += c
+
+    def is_block_tag(self,tag):
+        return (tag in ['article', 'header', 'aside', 'hgroup', 'blockquote',
+            'hr', 'iframe', 'body', 'li', 'map', 'button', 'object', 'canvas',
+            'ol', 'caption', 'output', 'col', 'p', 'colgroup', 'pre', 'dd',
+            'progress', 'div', 'section', 'dl', 'table', 'td', 'dt',
+            'tbody', 'embed', 'textarea', 'fieldset', 'tfoot', 'figcaption',
+            'th', 'figure', 'thead', 'footer', 'tr', 'form', 'ul',
+            'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'video', 'script', 'style'])
+
+def normalize_html(html):
+    r"""
+    Return normalized form of HTML which ignores insignificant output
+    differences:
+
+    * Multiple inner whitespaces are collapsed to a single space (except
+      in pre tags).
+    * Outer whitespace (outside block-level tags) is removed.
+    * Self-closing tags are converted to open tags.
+    * Attributes are sorted and lowercased.
+    * References are converted to unicode, except that '<', '>', '&', and
+      '&' are rendered using entities.
+    """
+    html_chunk_re = re.compile("(\<!\[CDATA\[.*?\]\]\>|\<[^>]*\>|[^<]+)")
+    try:
+        parser = MyHTMLParser()
+        # We work around HTMLParser's limitations parsing CDATA
+        # by breaking the input into chunks and passing CDATA chunks
+        # through verbatim.
+        for chunk in re.finditer(html_chunk_re, html):
+            if chunk.group(0)[:8] == "<![CDATA":
+                parser.output += chunk.group(0)
+            else:
+                parser.feed(chunk.group(0).decode(encoding='UTF-8'))
+        parser.close()
+        return parser.output
+    except HTMLParseError as e:
+        sys.stderr.write("Normalization error: " + e.msg + "\n")
+        return html  # on error, return unnormalized HTML