1 // Copyright 2008 The RE2 Authors.  All Rights Reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4 
5 // Exhaustive testing of regular expression matching.
6 
7 #include "util/test.h"
8 #include "re2/re2.h"
9 #include "re2/testing/exhaustive_tester.h"
10 
11 DECLARE_string(regexp_engines);
12 
13 namespace re2 {
14 
15 // Test empty string matches (aka "(?:)")
TEST(EmptyString,Exhaustive)16 TEST(EmptyString, Exhaustive) {
17   ExhaustiveTest(2, 2, Split(" ", "(?:) a"),
18                  RegexpGenerator::EgrepOps(),
19                  5, Split("", "ab"), "", "");
20 }
21 
22 // Test escaped versions of regexp syntax.
TEST(Punctuation,Literals)23 TEST(Punctuation, Literals) {
24   vector<string> alphabet = Explode("()*+?{}[]\\^$.");
25   vector<string> escaped = alphabet;
26   for (int i = 0; i < escaped.size(); i++)
27     escaped[i] = "\\" + escaped[i];
28   ExhaustiveTest(1, 1, escaped, RegexpGenerator::EgrepOps(),
29                  2, alphabet, "", "");
30 }
31 
32 // Test ^ $ . \A \z in presence of line endings.
33 // Have to wrap the empty-width ones in (?:) so that
34 // they can be repeated -- PCRE rejects ^* but allows (?:^)*
TEST(LineEnds,Exhaustive)35 TEST(LineEnds, Exhaustive) {
36   ExhaustiveTest(2, 2, Split(" ", "(?:^) (?:$) . a \\n (?:\\A) (?:\\z)"),
37                  RegexpGenerator::EgrepOps(),
38                  4, Explode("ab\n"), "", "");
39 }
40 
41 // Test what does and does not match \n.
42 // This would be a good test, except that PCRE seems to have a bug:
43 // in single-byte character set mode (the default),
44 // [^a] matches \n, but in UTF-8 mode it does not.
45 // So when we run the test, the tester complains that
46 // we don't agree with PCRE, but it's PCRE that is at fault.
47 // For what it's worth, Perl gets this right (matches
48 // regardless of whether UTF-8 input is selected):
49 //
50 //     #!/usr/bin/perl
51 //     use POSIX qw(locale_h);
52 //     print "matches in latin1\n" if "\n" =~ /[^a]/;
53 //     setlocale("en_US.utf8");
54 //     print "matches in utf8\n" if "\n" =~ /[^a]/;
55 //
56 // The rule chosen for RE2 is that by default, like Perl,
57 // dot does not match \n but negated character classes [^a] do.
58 // (?s) will allow dot to match \n; there is no way in RE2
59 // to stop [^a] from matching \n, though the underlying library
60 // provides a mechanism, and RE2 could add new syntax if needed.
61 //
62 // TEST(Newlines, Exhaustive) {
63 //   vector<string> empty_vector;
64 //   ExhaustiveTest(1, 1, Split(" ", "\\n . a [^a]"),
65 //                  RegexpGenerator::EgrepOps(),
66 //                  4, Explode("a\n"), "");
67 // }
68 
69 }  // namespace re2
70 
71