Add an option to capitalize margin and float properties

The option is disabled by default, that weird idea comes from a weird
outlook.com behaviour to handle margin and float properties only if the
first letter is uppercase.

See https://www.emailonacid.com/blog/article/email-development/outlook.com-does-support-margins

premailer/__main__.py

@@ -64,6 +64,12 @@ def main(args):
         action="store_true", dest="remove_classes"
     )
 
+    parser.add_argument(
+        "--capitalize-float-margin", default=False,
+        help="Capitalize float and margin properties for outlook.com compat.",
+        action="store_true", dest="capitalize_float_margin"
+    )
+
     parser.add_argument(
         "--strip-important", default=False,
         help="Remove '!important' for all css declarations.",

premailer/premailer.py

@@ -85,8 +85,27 @@ def _cache_parse_css_string(css_body, validate=True):
     """
     return cssutils.parseString(css_body, validate=validate)
 
+
+def capitalize_float_margin(css_body):
+    """Capitalize float and margin CSS property names
+    """
+    def _capitalize_property(match):
+        return '{0}:{1}{2}'.format(
+            match.group('property').capitalize(),
+            match.group('value'),
+            match.group('terminator'))
+
+    return _lowercase_margin_float_rule.sub(_capitalize_property, css_body)
+
+
 _element_selector_regex = re.compile(r'(^|\s)\w')
 _cdata_regex = re.compile(r'\<\!\[CDATA\[(.*?)\]\]\>', re.DOTALL)
+_lowercase_margin_float_rule = re.compile(
+    r'''(?P<property>margin(-(top|bottom|left|right))?|float)
+        :
+        (?P<value>.*?)
+        (?P<terminator>$|;)''',
+    re.IGNORECASE | re.VERBOSE)
 _importants = re.compile('\s*!important')
 # These selectors don't apply to all elements. Rather, they specify
 # which elements to apply to.
@@ -104,6 +123,7 @@ class Premailer(object):
                  keep_style_tags=False,
                  include_star_selectors=False,
                  remove_classes=True,
+                 capitalize_float_margin=False,
                  strip_important=True,
                  external_styles=None,
                  css_text=None,
@@ -126,6 +146,7 @@ class Premailer(object):
         # this will always preserve the original css
         self.keep_style_tags = keep_style_tags
         self.remove_classes = remove_classes
+        self.capitalize_float_margin = capitalize_float_margin
         # whether to process or ignore selectors like '* { foo:bar; }'
         self.include_star_selectors = include_star_selectors
         if isinstance(external_styles, STR_TYPE):
@@ -420,6 +441,14 @@ class Premailer(object):
                 parent = item.getparent()
                 del parent.attrib['class']
 
+        # Capitalize Margin properties
+        # To fix weird outlook bug
+        # https://www.emailonacid.com/blog/article/email-development/outlook.com-does-support-margins
+        if self.capitalize_float_margin:
+            for item in page.xpath('//@style'):
+                mangled = capitalize_float_margin(item)
+                item.getparent().attrib['style'] = mangled
+
         # Add align attributes to images if they have a CSS float value of
         # right or left. Outlook (both on desktop and on the web) are bad at
         # understanding floats, but they do understand the HTML align attrib.

premailer/tests/test_merge_style.py

@@ -16,9 +16,3 @@ class TestMergeStyle(unittest.TestCase):
         # Invalid syntax does not raise
         inline = '{color:pink} :hover{color:purple} :active{color:red}'
         merge_styles(inline, [], [])
-
-    def test_important_rule(self):
-        # No exception after #133
-        csstext = 'font-size:1px !important'
-        parsed_csstext = csstext_to_pairs(csstext)
-        self.assertEqual(('font-size', '1px'), parsed_csstext[0])

premailer/tests/test_premailer.py

@@ -828,6 +828,45 @@ ical-align:middle" bgcolor="red" valign="middle">Cell 2</td>
 
         compare_html(expect_html, result_html)
 
+    def test_uppercase_margin(self):
+        """Option to comply with outlook.com
+
+        https://emailonacid.com/blog/article/email-development/outlook.com-does-support-margins
+        """
+
+        html = """<html>
+<head>
+<title>Title</title>
+</head>
+<style>
+h1 {margin: 0}
+h2 {margin-top:0;margin-bottom:0;margin-left:0;margin-right:0}
+</style>
+<body>
+<h1>a</h1>
+<h2>
+b
+</h2>
+</body>
+</html>"""
+
+        expect_html = """<html>
+<head>
+<title>Title</title>
+</head>
+<body>
+<h1 style="Margin:0">a</h1>
+<h2 style="Margin-bottom:0; Margin-left:0; Margin-right:0; Margin-top:0">
+b
+</h2>
+</body>
+</html>"""
+
+        p = Premailer(html, capitalize_float_margin=True)
+        result_html = p.transform()
+
+        compare_html(expect_html, result_html)
+
     def test_strip_important(self):
         """Get rid of !important. Makes no sense inline."""
         html = """<html>

premailer/tests/test_utils.py

@@ -0,0 +1,19 @@
+import unittest
+
+from premailer.premailer import capitalize_float_margin
+
+
+class UtilsTestCase(unittest.TestCase):
+    def testcapitalize_float_margin(self):
+        self.assertEqual(
+            capitalize_float_margin('margin:1em'),
+            'Margin:1em')
+        self.assertEqual(
+            capitalize_float_margin('margin-left:1em'),
+            'Margin-left:1em')
+        self.assertEqual(
+            capitalize_float_margin('float:right;'),
+            'Float:right;')
+        self.assertEqual(
+            capitalize_float_margin('float:right;color:red;margin:0'),
+            'Float:right;color:red;Margin:0')