Add fallback to @media type "all" (#533)

* Add fallback to @media type "all" (#498)

* Add unittests for css @media rule

tests/test_css_media_rule.py

@@ -0,0 +1,67 @@
+from unittest import TestCase
+
+from xhtml2pdf.w3c.css import CSSBuilder, CSSParser
+
+
+class CssMediaRuleTest(TestCase):
+    """
+    Test cases for the css @media rule (https://www.w3.org/TR/css3-mediaqueries/)
+    """
+
+    def setUp(self):
+        """
+        Setup css parser for all test cases
+        """
+        self.parser = CSSParser(CSSBuilder(mediumSet=["all"]))
+
+    def test_media_all(self):
+        """
+        Test if the rule "@media all {" works
+        """
+
+        media_all = """
+            @media all {
+                p { color: yellow; }
+            }
+        """
+
+        selector_media_all = self.parser.parse(media_all)[0]
+        css_media_all = self._get_first_dict_value(selector_media_all)
+
+        self.assertDictEqual(css_media_all, {"color": "yellow"})
+
+    def test_media_all_and(self):
+        """
+        Test if the rule "@media all and (...) {" works
+        """
+
+        media_all_and = """
+            @media all and (max-width: 500px) {
+                p { color: yellow; }
+            }
+        """
+
+        selector_media_all_and = self.parser.parse(media_all_and)[0]
+        css_media_all_and = self._get_first_dict_value(selector_media_all_and)
+
+        self.assertDictEqual(css_media_all_and, {"color": "yellow"})
+
+    def test_media_all_default(self):
+        """
+        Test if the rule "@media (...) {" works (no media type defaults to "all")
+        """
+
+        media_all_default = """
+            @media (max-width: 500px) {
+                p { color: yellow; }
+            }
+        """
+
+        selector_media_all_default = self.parser.parse(media_all_default)[0]
+        css_media_all_default = self._get_first_dict_value(selector_media_all_default)
+
+        self.assertDictEqual(css_media_all_default, {"color": "yellow"})
+
+    @staticmethod
+    def _get_first_dict_value(dictionary):
+        return dictionary[list(dictionary.keys())[0]]

xhtml2pdf/w3c/cssParser.py

@@ -693,10 +693,11 @@ def _parseAtMedia(self, src):
         mediums = []
         while src and src[0] != '{':
             medium, src = self._getIdent(src)
-            if medium is None:
-                raise self.ParseError('@media rule expected media identifier', src, ctxsrc)
             # make "and ... {" work
-            if medium == 'and':
+            if medium in (None, 'and'):
+                # default to mediatype "all"
+                if medium is None:
+                    mediums.append('all')
                 # strip up to curly bracket
                 pattern = re.compile('.*({.*)')
                 match = re.match(pattern, src)