1 files changed, 509 insertions, 0 deletions
diff --git a/src/third_party/re2/dist/re2/testing/parse_test.cc b/src/third_party/re2/dist/re2/testing/parse_test.cc
new file mode 100644
index 00000000000..e571127b551
--- /dev/null
+++ b/src/third_party/re2/dist/re2/testing/parse_test.cc
@@ -0,0 +1,509 @@
+// Copyright 2006 The RE2 Authors.  All Rights Reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Test parse.cc, dump.cc, and tostring.cc.
+
+#include <string>
+
+#include "util/test.h"
+#include "util/logging.h"
+#include "re2/regexp.h"
+
+namespace re2 {
+
+// In the past, we used 1<<30 here and zeroed the bit later, but that
+// has undefined behaviour, so now we use an internal-only flag because
+// otherwise we would have to introduce a new flag value just for this.
+static const Regexp::ParseFlags TestZeroFlags = Regexp::WasDollar;
+
+struct Test {
+  const char* regexp;
+  const char* parse;
+  Regexp::ParseFlags flags;
+};
+
+static Regexp::ParseFlags kTestFlags = Regexp::MatchNL |
+                                       Regexp::PerlX |
+                                       Regexp::PerlClasses |
+                                       Regexp::UnicodeGroups;
+
+static Test tests[] = {
+  // Base cases
+  { "a", "lit{a}" },
+  { "a.", "cat{lit{a}dot{}}" },
+  { "a.b", "cat{lit{a}dot{}lit{b}}" },
+  { "ab", "str{ab}" },
+  { "a.b.c", "cat{lit{a}dot{}lit{b}dot{}lit{c}}" },
+  { "abc", "str{abc}" },
+  { "a|^", "alt{lit{a}bol{}}" },
+  { "a|b", "cc{0x61-0x62}" },
+  { "(a)", "cap{lit{a}}" },
+  { "(a)|b", "alt{cap{lit{a}}lit{b}}" },
+  { "a*", "star{lit{a}}" },
+  { "a+", "plus{lit{a}}" },
+  { "a?", "que{lit{a}}" },
+  { "a{2}", "rep{2,2 lit{a}}" },
+  { "a{2,3}", "rep{2,3 lit{a}}" },
+  { "a{2,}", "rep{2,-1 lit{a}}" },
+  { "a*?", "nstar{lit{a}}" },
+  { "a+?", "nplus{lit{a}}" },
+  { "a??", "nque{lit{a}}" },
+  { "a{2}?", "nrep{2,2 lit{a}}" },
+  { "a{2,3}?", "nrep{2,3 lit{a}}" },
+  { "a{2,}?", "nrep{2,-1 lit{a}}" },
+  { "", "emp{}" },
+  { "|", "alt{emp{}emp{}}" },
+  { "|x|", "alt{emp{}lit{x}emp{}}" },
+  { ".", "dot{}" },
+  { "^", "bol{}" },
+  { "$", "eol{}" },
+  { "\\|", "lit{|}" },
+  { "\\(", "lit{(}" },
+  { "\\)", "lit{)}" },
+  { "\\*", "lit{*}" },
+  { "\\+", "lit{+}" },
+  { "\\?", "lit{?}" },
+  { "{", "lit{{}" },
+  { "}", "lit{}}" },
+  { "\\.", "lit{.}" },
+  { "\\^", "lit{^}" },
+  { "\\$", "lit{$}" },
+  { "\\\\", "lit{\\}" },
+  { "[ace]", "cc{0x61 0x63 0x65}" },
+  { "[abc]", "cc{0x61-0x63}" },
+  { "[a-z]", "cc{0x61-0x7a}" },
+  { "[a]", "lit{a}" },
+  { "\\-", "lit{-}" },
+  { "-", "lit{-}" },
+  { "\\_", "lit{_}" },
+
+  // Posix and Perl extensions
+  { "[[:lower:]]", "cc{0x61-0x7a}" },
+  { "[a-z]", "cc{0x61-0x7a}" },
+  { "[^[:lower:]]", "cc{0-0x60 0x7b-0x10ffff}" },
+  { "[[:^lower:]]", "cc{0-0x60 0x7b-0x10ffff}" },
+  { "(?i)[[:lower:]]", "cc{0x41-0x5a 0x61-0x7a 0x17f 0x212a}" },
+  { "(?i)[a-z]", "cc{0x41-0x5a 0x61-0x7a 0x17f 0x212a}" },
+  { "(?i)[^[:lower:]]", "cc{0-0x40 0x5b-0x60 0x7b-0x17e 0x180-0x2129 0x212b-0x10ffff}" },
+  { "(?i)[[:^lower:]]", "cc{0-0x40 0x5b-0x60 0x7b-0x17e 0x180-0x2129 0x212b-0x10ffff}" },
+  { "\\d", "cc{0x30-0x39}" },
+  { "\\D", "cc{0-0x2f 0x3a-0x10ffff}" },
+  { "\\s", "cc{0x9-0xa 0xc-0xd 0x20}" },
+  { "\\S", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}" },
+  { "\\w", "cc{0x30-0x39 0x41-0x5a 0x5f 0x61-0x7a}" },
+  { "\\W", "cc{0-0x2f 0x3a-0x40 0x5b-0x5e 0x60 0x7b-0x10ffff}" },
+  { "(?i)\\w", "cc{0x30-0x39 0x41-0x5a 0x5f 0x61-0x7a 0x17f 0x212a}" },
+  { "(?i)\\W", "cc{0-0x2f 0x3a-0x40 0x5b-0x5e 0x60 0x7b-0x17e 0x180-0x2129 0x212b-0x10ffff}" },
+  { "[^\\\\]", "cc{0-0x5b 0x5d-0x10ffff}" },
+  { "\\C", "byte{}" },
+
+  // Unicode, negatives, and a double negative.
+  { "\\p{Braille}", "cc{0x2800-0x28ff}" },
+  { "\\P{Braille}", "cc{0-0x27ff 0x2900-0x10ffff}" },
+  { "\\p{^Braille}", "cc{0-0x27ff 0x2900-0x10ffff}" },
+  { "\\P{^Braille}", "cc{0x2800-0x28ff}" },
+
+  // More interesting regular expressions.
+  { "a{,2}", "str{a{,2}}" },
+  { "\\.\\^\\$\\\\", "str{.^$\\}" },
+  { "[a-zABC]", "cc{0x41-0x43 0x61-0x7a}" },
+  { "[^a]", "cc{0-0x60 0x62-0x10ffff}" },
+  { "[\xce\xb1-\xce\xb5\xe2\x98\xba]", "cc{0x3b1-0x3b5 0x263a}" },  // utf-8
+  { "a*{", "cat{star{lit{a}}lit{{}}" },
+
+  // Test precedences
+  { "(?:ab)*", "star{str{ab}}" },
+  { "(ab)*", "star{cap{str{ab}}}" },
+  { "ab|cd", "alt{str{ab}str{cd}}" },
+  { "a(b|c)d", "cat{lit{a}cap{cc{0x62-0x63}}lit{d}}" },
+
+  // Test squashing of **, ++, ?? et cetera.
+  { "(?:(?:a)*)*", "star{lit{a}}" },
+  { "(?:(?:a)+)+", "plus{lit{a}}" },
+  { "(?:(?:a)?)?", "que{lit{a}}" },
+  { "(?:(?:a)*)+", "star{lit{a}}" },
+  { "(?:(?:a)*)?", "star{lit{a}}" },
+  { "(?:(?:a)+)*", "star{lit{a}}" },
+  { "(?:(?:a)+)?", "star{lit{a}}" },
+  { "(?:(?:a)?)*", "star{lit{a}}" },
+  { "(?:(?:a)?)+", "star{lit{a}}" },
+
+  // Test flattening.
+  { "(?:a)", "lit{a}" },
+  { "(?:ab)(?:cd)", "str{abcd}" },
+  { "(?:a|b)|(?:c|d)", "cc{0x61-0x64}" },
+  { "a|c", "cc{0x61 0x63}" },
+  { "a|[cd]", "cc{0x61 0x63-0x64}" },
+  { "a|.", "dot{}" },
+  { "[ab]|c", "cc{0x61-0x63}" },
+  { "[ab]|[cd]", "cc{0x61-0x64}" },
+  { "[ab]|.", "dot{}" },
+  { ".|c", "dot{}" },
+  { ".|[cd]", "dot{}" },
+  { ".|.", "dot{}" },
+
+  // Test Perl quoted literals
+  { "\\Q+|*?{[\\E", "str{+|*?{[}" },
+  { "\\Q+\\E+", "plus{lit{+}}" },
+  { "\\Q\\\\E", "lit{\\}" },
+  { "\\Q\\\\\\E", "str{\\\\}" },
+  { "\\Qa\\E*", "star{lit{a}}" },
+  { "\\Qab\\E*", "cat{lit{a}star{lit{b}}}" },
+  { "\\Qabc\\E*", "cat{str{ab}star{lit{c}}}" },
+
+  // Test Perl \A and \z
+  { "(?m)^", "bol{}" },
+  { "(?m)$", "eol{}" },
+  { "(?-m)^", "bot{}" },
+  { "(?-m)$", "eot{}" },
+  { "(?m)\\A", "bot{}" },
+  { "(?m)\\z", "eot{\\z}" },
+  { "(?-m)\\A", "bot{}" },
+  { "(?-m)\\z", "eot{\\z}" },
+
+  // Test named captures
+  { "(?P<name>a)", "cap{name:lit{a}}" },
+  { "(?P<中文>a)", "cap{中文:lit{a}}" },
+
+  // Case-folded literals
+  { "[Aa]", "litfold{a}" },
+
+  // Strings
+  { "abcde", "str{abcde}" },
+  { "[Aa][Bb]cd", "cat{strfold{ab}str{cd}}" },
+
+  // Reported bug involving \n leaking in despite use of NeverNL.
+  { "[^ ]", "cc{0-0x9 0xb-0x1f 0x21-0x10ffff}", TestZeroFlags },
+  { "[^ ]", "cc{0-0x9 0xb-0x1f 0x21-0x10ffff}", Regexp::FoldCase },
+  { "[^ ]", "cc{0-0x9 0xb-0x1f 0x21-0x10ffff}", Regexp::NeverNL },
+  { "[^ ]", "cc{0-0x9 0xb-0x1f 0x21-0x10ffff}", Regexp::NeverNL | Regexp::FoldCase },
+  { "[^ \f]", "cc{0-0x9 0xb 0xd-0x1f 0x21-0x10ffff}", TestZeroFlags },
+  { "[^ \f]", "cc{0-0x9 0xb 0xd-0x1f 0x21-0x10ffff}", Regexp::FoldCase },
+  { "[^ \f]", "cc{0-0x9 0xb 0xd-0x1f 0x21-0x10ffff}", Regexp::NeverNL },
+  { "[^ \f]", "cc{0-0x9 0xb 0xd-0x1f 0x21-0x10ffff}", Regexp::NeverNL | Regexp::FoldCase },
+  { "[^ \r]", "cc{0-0x9 0xb-0xc 0xe-0x1f 0x21-0x10ffff}", TestZeroFlags },
+  { "[^ \r]", "cc{0-0x9 0xb-0xc 0xe-0x1f 0x21-0x10ffff}", Regexp::FoldCase },
+  { "[^ \r]", "cc{0-0x9 0xb-0xc 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL },
+  { "[^ \r]", "cc{0-0x9 0xb-0xc 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL | Regexp::FoldCase },
+  { "[^ \v]", "cc{0-0x9 0xc-0x1f 0x21-0x10ffff}", TestZeroFlags },
+  { "[^ \v]", "cc{0-0x9 0xc-0x1f 0x21-0x10ffff}", Regexp::FoldCase },
+  { "[^ \v]", "cc{0-0x9 0xc-0x1f 0x21-0x10ffff}", Regexp::NeverNL },
+  { "[^ \v]", "cc{0-0x9 0xc-0x1f 0x21-0x10ffff}", Regexp::NeverNL | Regexp::FoldCase },
+  { "[^ \t]", "cc{0-0x8 0xb-0x1f 0x21-0x10ffff}", TestZeroFlags },
+  { "[^ \t]", "cc{0-0x8 0xb-0x1f 0x21-0x10ffff}", Regexp::FoldCase },
+  { "[^ \t]", "cc{0-0x8 0xb-0x1f 0x21-0x10ffff}", Regexp::NeverNL },
+  { "[^ \t]", "cc{0-0x8 0xb-0x1f 0x21-0x10ffff}", Regexp::NeverNL | Regexp::FoldCase },
+  { "[^ \r\f\v]", "cc{0-0x9 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL },
+  { "[^ \r\f\v]", "cc{0-0x9 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL | Regexp::FoldCase },
+  { "[^ \r\f\t\v]", "cc{0-0x8 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL },
+  { "[^ \r\f\t\v]", "cc{0-0x8 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL | Regexp::FoldCase },
+  { "[^ \r\n\f\t\v]", "cc{0-0x8 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL },
+  { "[^ \r\n\f\t\v]", "cc{0-0x8 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL | Regexp::FoldCase },
+  { "[^ \r\n\f\t]", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL },
+  { "[^ \r\n\f\t]", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}", Regexp::NeverNL | Regexp::FoldCase },
+  { "[^\t-\n\f-\r ]", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}",
+    Regexp::PerlClasses },
+  { "[^\t-\n\f-\r ]", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}",
+    Regexp::PerlClasses | Regexp::FoldCase },
+  { "[^\t-\n\f-\r ]", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}",
+    Regexp::PerlClasses | Regexp::NeverNL },
+  { "[^\t-\n\f-\r ]", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}",
+    Regexp::PerlClasses | Regexp::NeverNL | Regexp::FoldCase },
+  { "\\S", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}",
+    Regexp::PerlClasses },
+  { "\\S", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}",
+    Regexp::PerlClasses | Regexp::FoldCase },
+  { "\\S", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}",
+    Regexp::PerlClasses | Regexp::NeverNL },
+  { "\\S", "cc{0-0x8 0xb 0xe-0x1f 0x21-0x10ffff}",
+    Regexp::PerlClasses | Regexp::NeverNL | Regexp::FoldCase },
+
+  // Bug in Regexp::ToString() that emitted [^], which
+  // would (obviously) fail to parse when fed back in.
+  { "[\\s\\S]", "cc{0-0x10ffff}" },
+};
+
+bool RegexpEqualTestingOnly(Regexp* a, Regexp* b) {
+  return Regexp::Equal(a, b);
+}
+
+void TestParse(const Test* tests, int ntests, Regexp::ParseFlags flags,
+               const std::string& title) {
+  Regexp** re = new Regexp*[ntests];
+  for (int i = 0; i < ntests; i++) {
+    RegexpStatus status;
+    Regexp::ParseFlags f = flags;
+    if (tests[i].flags != 0) {
+      f = tests[i].flags & ~TestZeroFlags;
+    }
+    re[i] = Regexp::Parse(tests[i].regexp, f, &status);
+    ASSERT_TRUE(re[i] != NULL)
+      << " " << tests[i].regexp << " " << status.Text();
+    std::string s = re[i]->Dump();
+    EXPECT_EQ(std::string(tests[i].parse), s)
+        << "Regexp: " << tests[i].regexp
+        << "\nparse: " << std::string(tests[i].parse)
+        << " s: " << s << " flag=" << f;
+  }
+
+  for (int i = 0; i < ntests; i++) {
+    for (int j = 0; j < ntests; j++) {
+      EXPECT_EQ(std::string(tests[i].parse) == std::string(tests[j].parse),
+                RegexpEqualTestingOnly(re[i], re[j]))
+        << "Regexp: " << tests[i].regexp << " " << tests[j].regexp;
+    }
+  }
+
+  for (int i = 0; i < ntests; i++)
+    re[i]->Decref();
+  delete[] re;
+}
+
+// Test that regexps parse to expected structures.
+TEST(TestParse, SimpleRegexps) {
+  TestParse(tests, arraysize(tests), kTestFlags, "simple");
+}
+
+Test foldcase_tests[] = {
+  { "AbCdE", "strfold{abcde}" },
+  { "[Aa]", "litfold{a}" },
+  { "a", "litfold{a}" },
+
+  // 0x17F is an old English long s (looks like an f) and folds to s.
+  // 0x212A is the Kelvin symbol and folds to k.
+  { "A[F-g]", "cat{litfold{a}cc{0x41-0x7a 0x17f 0x212a}}" },  // [Aa][A-z...]
+  { "[[:upper:]]", "cc{0x41-0x5a 0x61-0x7a 0x17f 0x212a}" },
+  { "[[:lower:]]", "cc{0x41-0x5a 0x61-0x7a 0x17f 0x212a}" },
+};
+
+// Test that parsing with FoldCase works.
+TEST(TestParse, FoldCase) {
+  TestParse(foldcase_tests, arraysize(foldcase_tests), Regexp::FoldCase, "foldcase");
+}
+
+Test literal_tests[] = {
+  { "(|)^$.[*+?]{5,10},\\", "str{(|)^$.[*+?]{5,10},\\}" },
+};
+
+// Test that parsing with Literal works.
+TEST(TestParse, Literal) {
+  TestParse(literal_tests, arraysize(literal_tests), Regexp::Literal, "literal");
+}
+
+Test matchnl_tests[] = {
+  { ".", "dot{}" },
+  { "\n", "lit{\n}" },
+  { "[^a]", "cc{0-0x60 0x62-0x10ffff}" },
+  { "[a\\n]", "cc{0xa 0x61}" },
+};
+
+// Test that parsing with MatchNL works.
+// (Also tested above during simple cases.)
+TEST(TestParse, MatchNL) {
+  TestParse(matchnl_tests, arraysize(matchnl_tests), Regexp::MatchNL, "with MatchNL");
+}
+
+Test nomatchnl_tests[] = {
+  { ".", "cc{0-0x9 0xb-0x10ffff}" },
+  { "\n", "lit{\n}" },
+  { "[^a]", "cc{0-0x9 0xb-0x60 0x62-0x10ffff}" },
+  { "[a\\n]", "cc{0xa 0x61}" },
+};
+
+// Test that parsing without MatchNL works.
+TEST(TestParse, NoMatchNL) {
+  TestParse(nomatchnl_tests, arraysize(nomatchnl_tests), Regexp::NoParseFlags, "without MatchNL");
+}
+
+Test prefix_tests[] = {
+  { "abc|abd", "cat{str{ab}cc{0x63-0x64}}" },
+  { "a(?:b)c|abd", "cat{str{ab}cc{0x63-0x64}}" },
+  { "abc|abd|aef|bcx|bcy",
+    "alt{cat{lit{a}alt{cat{lit{b}cc{0x63-0x64}}str{ef}}}"
+      "cat{str{bc}cc{0x78-0x79}}}" },
+  { "abc|x|abd", "alt{str{abc}lit{x}str{abd}}" },
+  { "(?i)abc|ABD", "cat{strfold{ab}cc{0x43-0x44 0x63-0x64}}" },
+  { "[ab]c|[ab]d", "cat{cc{0x61-0x62}cc{0x63-0x64}}" },
+  { ".c|.d", "cat{cc{0-0x9 0xb-0x10ffff}cc{0x63-0x64}}" },
+  { "\\Cc|\\Cd", "cat{byte{}cc{0x63-0x64}}" },
+  { "x{2}|x{2}[0-9]",
+    "cat{rep{2,2 lit{x}}alt{emp{}cc{0x30-0x39}}}" },
+  { "x{2}y|x{2}[0-9]y",
+    "cat{rep{2,2 lit{x}}alt{lit{y}cat{cc{0x30-0x39}lit{y}}}}" },
+  { "n|r|rs",
+    "alt{lit{n}cat{lit{r}alt{emp{}lit{s}}}}" },
+  { "n|rs|r",
+    "alt{lit{n}cat{lit{r}alt{lit{s}emp{}}}}" },
+  { "r|rs|n",
+    "alt{cat{lit{r}alt{emp{}lit{s}}}lit{n}}" },
+  { "rs|r|n",
+    "alt{cat{lit{r}alt{lit{s}emp{}}}lit{n}}" },
+  { "a\\C*?c|a\\C*?b",
+    "cat{lit{a}alt{cat{nstar{byte{}}lit{c}}cat{nstar{byte{}}lit{b}}}}" },
+  { "^/a/bc|^/a/de",
+    "cat{bol{}cat{str{/a/}alt{str{bc}str{de}}}}" },
+  // In the past, factoring was limited to kFactorAlternationMaxDepth (8).
+  { "a|aa|aaa|aaaa|aaaaa|aaaaaa|aaaaaaa|aaaaaaaa|aaaaaaaaa|aaaaaaaaaa",
+    "cat{lit{a}alt{emp{}" "cat{lit{a}alt{emp{}" "cat{lit{a}alt{emp{}"
+    "cat{lit{a}alt{emp{}" "cat{lit{a}alt{emp{}" "cat{lit{a}alt{emp{}"
+    "cat{lit{a}alt{emp{}" "cat{lit{a}alt{emp{}" "cat{lit{a}alt{emp{}"
+    "lit{a}}}}}}}}}}}}}}}}}}}" },
+  { "a|aardvark|aardvarks|abaci|aback|abacus|abacuses|abaft|abalone|abalones",
+    "cat{lit{a}alt{emp{}cat{str{ardvark}alt{emp{}lit{s}}}"
+    "cat{str{ba}alt{cat{lit{c}alt{cc{0x69 0x6b}cat{str{us}alt{emp{}str{es}}}}}"
+    "str{ft}cat{str{lone}alt{emp{}lit{s}}}}}}}" },
+};
+
+// Test that prefix factoring works.
+TEST(TestParse, Prefix) {
+  TestParse(prefix_tests, arraysize(prefix_tests), Regexp::PerlX, "prefix");
+}
+
+Test nested_tests[] = {
+  { "((((((((((x{2}){2}){2}){2}){2}){2}){2}){2}){2}))",
+    "cap{cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 lit{x}}}}}}}}}}}}}}}}}}}}" },
+  { "((((((((((x{1}){2}){2}){2}){2}){2}){2}){2}){2}){2})",
+    "cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{1,1 lit{x}}}}}}}}}}}}}}}}}}}}}" },
+  { "((((((((((x{0}){2}){2}){2}){2}){2}){2}){2}){2}){2})",
+    "cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 cap{rep{0,0 lit{x}}}}}}}}}}}}}}}}}}}}}" },
+  { "((((((x{2}){2}){2}){5}){5}){5})",
+    "cap{rep{5,5 cap{rep{5,5 cap{rep{5,5 cap{rep{2,2 cap{rep{2,2 cap{rep{2,2 lit{x}}}}}}}}}}}}}" },
+};
+
+// Test that nested repetition works.
+TEST(TestParse, Nested) {
+  TestParse(nested_tests, arraysize(nested_tests), Regexp::PerlX, "nested");
+}
+
+// Invalid regular expressions
+const char* badtests[] = {
+  "(",
+  ")",
+  "(a",
+  "(a|b|",
+  "(a|b",
+  "[a-z",
+  "([a-z)",
+  "x{1001}",
+  "\xff",      // Invalid UTF-8
+  "[\xff]",
+  "[\\\xff]",
+  "\\\xff",
+  "(?P<name>a",
+  "(?P<name>",
+  "(?P<name",
+  "(?P<x y>a)",
+  "(?P<>a)",
+  "[a-Z]",
+  "(?i)[a-Z]",
+  "a{100000}",
+  "a{100000,}",
+  "((((((((((x{2}){2}){2}){2}){2}){2}){2}){2}){2}){2})",
+  "(((x{7}){11}){13})",
+  "\\Q\\E*",
+};
+
+// Valid in Perl, bad in POSIX
+const char* only_perl[] = {
+ "[a-b-c]",
+ "\\Qabc\\E",
+ "\\Q*+?{[\\E",
+ "\\Q\\\\E",
+ "\\Q\\\\\\E",
+ "\\Q\\\\\\\\E",
+ "\\Q\\\\\\\\\\E",
+ "(?:a)",
+ "(?P<name>a)",
+};
+
+// Valid in POSIX, bad in Perl.
+const char* only_posix[] = {
+  "a++",
+  "a**",
+  "a?*",
+  "a+*",
+  "a{1}*",
+};
+
+// Test that parser rejects bad regexps.
+TEST(TestParse, InvalidRegexps) {
+  for (size_t i = 0; i < arraysize(badtests); i++) {
+    ASSERT_TRUE(Regexp::Parse(badtests[i], Regexp::PerlX, NULL) == NULL)
+      << " " << badtests[i];
+    ASSERT_TRUE(Regexp::Parse(badtests[i], Regexp::NoParseFlags, NULL) == NULL)
+      << " " << badtests[i];
+  }
+  for (size_t i = 0; i < arraysize(only_posix); i++) {
+    ASSERT_TRUE(Regexp::Parse(only_posix[i], Regexp::PerlX, NULL) == NULL)
+      << " " << only_posix[i];
+    Regexp* re = Regexp::Parse(only_posix[i], Regexp::NoParseFlags, NULL);
+    ASSERT_TRUE(re != NULL) << " " << only_posix[i];
+    re->Decref();
+  }
+  for (size_t i = 0; i < arraysize(only_perl); i++) {
+    ASSERT_TRUE(Regexp::Parse(only_perl[i], Regexp::NoParseFlags, NULL) == NULL)
+      << " " << only_perl[i];
+    Regexp* re = Regexp::Parse(only_perl[i], Regexp::PerlX, NULL);
+    ASSERT_TRUE(re != NULL) << " " << only_perl[i];
+    re->Decref();
+  }
+}
+
+// Test that ToString produces original regexp or equivalent one.
+TEST(TestToString, EquivalentParse) {
+  for (size_t i = 0; i < arraysize(tests); i++) {
+    RegexpStatus status;
+    Regexp::ParseFlags f = kTestFlags;
+    if (tests[i].flags != 0) {
+      f = tests[i].flags & ~TestZeroFlags;
+    }
+    Regexp* re = Regexp::Parse(tests[i].regexp, f, &status);
+    ASSERT_TRUE(re != NULL) << " " << tests[i].regexp << " " << status.Text();
+    std::string s = re->Dump();
+    EXPECT_EQ(std::string(tests[i].parse), s)
+        << "Regexp: " << tests[i].regexp
+        << "\nparse: " << std::string(tests[i].parse)
+        << " s: " << s << " flag=" << f;
+    std::string t = re->ToString();
+    if (t != tests[i].regexp) {
+      // If ToString didn't return the original regexp,
+      // it must have found one with fewer parens.
+      // Unfortunately we can't check the length here, because
+      // ToString produces "\\{" for a literal brace,
+      // but "{" is a shorter equivalent.
+      // ASSERT_LT(t.size(), strlen(tests[i].regexp))
+      //     << " t=" << t << " regexp=" << tests[i].regexp;
+
+      // Test that if we parse the new regexp we get the same structure.
+      Regexp* nre = Regexp::Parse(t, Regexp::MatchNL | Regexp::PerlX, &status);
+      ASSERT_TRUE(nre != NULL) << " reparse " << t << " " << status.Text();
+      std::string ss = nre->Dump();
+      std::string tt = nre->ToString();
+      if (s != ss || t != tt)
+        LOG(INFO) << "ToString(" << tests[i].regexp << ") = " << t;
+      EXPECT_EQ(s, ss);
+      EXPECT_EQ(t, tt);
+      nre->Decref();
+    }
+    re->Decref();
+  }
+}
+
+// Test that capture error args are correct.
+TEST(NamedCaptures, ErrorArgs) {
+  RegexpStatus status;
+  Regexp* re;
+
+  re = Regexp::Parse("test(?P<name", Regexp::LikePerl, &status);
+  EXPECT_TRUE(re == NULL);
+  EXPECT_EQ(status.code(), kRegexpBadNamedCapture);
+  EXPECT_EQ(status.error_arg(), "(?P<name");
+
+  re = Regexp::Parse("test(?P<space bar>z)", Regexp::LikePerl, &status);
+  EXPECT_TRUE(re == NULL);
+  EXPECT_EQ(status.code(), kRegexpBadNamedCapture);
+  EXPECT_EQ(status.error_arg(), "(?P<space bar>");
+}
+
+}  // namespace re2