Issue 6877 - Only parse headers in the first line of the filter list

tests/test_parser.py

 # This file is part of Adblock Plus <https://adblockplus.org/>,
 # Copyright (C) 2006-present eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
@@ skipping 142 matching lines @@
     assert line.target == 'foo:bar/baz.txt'
 
 
 def test_parse_bad_instruction():
     with pytest.raises(ParseError):
         parse_line('%foo bar%')
 
 
 def test_parse_start():
     # Header-line lines are headers.
-    assert parse_line('[Adblock Plus 1.1]', mode='start').type == 'header'
-    # But space is not allowed in headers.
-    assert parse_line(' [Adblock Plus 1.1]', mode='start').type == 'filter'
-    assert parse_line('[Adblock Plus 1.1] ', mode='start').type == 'filter'
-
-    with pytest.raises(ParseError):
-        # Invalid headers cause exceptions.
-        parse_line('[Adblock 1.1]', mode='start')
+    assert parse_line('[Adblock Plus 1.1]', 'start').type == 'header'
+    # Even if they have extra characters around.
+    assert parse_line('foo[Adblock Plus 1.1] bar', 'start').type == 'header'
+
+    with pytest.raises(ParseError):
+        # But the inside of the header needs to be right.
+        parse_line('[Adblock Minus 1.1]', 'start').type
+
+    with pytest.raises(ParseError):
+        # Really right!
+        parse_line('[Adblock 1.1]', 'start')
 
     # Metadata-like lines are metadata.
-    assert parse_line('! Foo: bar', mode='metadata').type == 'metadata'
+    assert parse_line('! Foo: bar', 'metadata').type == 'metadata'
 
 
 def test_parse_metadata():
     # Header-like lines are just filters.
-    assert parse_line('[Adblock 1.1]', mode='metadata').type == 'filter'
+    assert parse_line('[Adblock 1.1]', 'metadata').type == 'filter'
     # Metadata-like lines are metadata.
-    assert parse_line('! Foo: bar', mode='metadata').type == 'metadata'
+    assert parse_line('! Foo: bar', 'metadata').type == 'metadata'
 
 
 def test_parse_body():
     # Header-like lines are just filters.
-    assert parse_line('[Adblock 1.1]', mode='body').type == 'filter'
+    assert parse_line('[Adblock 1.1]', 'body').type == 'filter'
     # Metadata-like lines are comments.
-    assert parse_line('! Foo: bar', mode='body').type == 'comment'
+    assert parse_line('! Foo: bar', 'body').type == 'comment'
     # But there's an exception for the checksum.
-    assert parse_line('! Checksum: 42', mode='body').type == 'metadata'
-
-
-def test_parse_invalid_mode():
+    assert parse_line('! Checksum: 42', 'body').type == 'metadata'
+
+
+def test_parse_invalid_position():
     with pytest.raises(ValueError):
-        parse_line('', mode='nonsense')
+        parse_line('', 'nonsense')
 
 
 def test_parse_filterlist():
     result = parse_filterlist(['[Adblock Plus 1.1]',
                                ' ! Last modified: 26 Jul 2018 02:10 UTC ',
                                '! Homepage  :  http://aaa.com/b',
                                '||example.com^',
                                '! Checksum: OaopkIiiAl77sSHk/VAWDA',
                                '! Note: bla bla'])
 
@@ skipping 12 matching lines @@
 def test_exception_timing():
     result = parse_filterlist(['! good line', '%bad line%'])
     assert next(result) == Comment('good line')
     with pytest.raises(ParseError):
         next(result)
 
 
 def test_parse_line_bytes():
     line = parse_line(b'! \xc3\xbc')
     assert line.text == '\xfc'