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29 //
30 // Author: wan@google.com (Zhanyong Wan)
31 //
32 // The Google C++ Testing Framework (Google Test)
33 //
34 // This header file defines the public API for death tests.  It is
35 // #included by gtest.h so a user doesn't need to include this
36 // directly.
37 
38 #ifndef GTEST_INCLUDE_GTEST_GTEST_DEATH_TEST_H_
39 #define GTEST_INCLUDE_GTEST_GTEST_DEATH_TEST_H_
40 
41 #include "gtest/internal/gtest-death-test-internal.h"
42 
43 namespace testing {
44 
45 // This flag controls the style of death tests.  Valid values are "threadsafe",
46 // meaning that the death test child process will re-execute the test binary
47 // from the start, running only a single death test, or "fast",
48 // meaning that the child process will execute the test logic immediately
49 // after forking.
50 GTEST_DECLARE_string_(death_test_style);
51 
52 #if GTEST_HAS_DEATH_TEST
53 
54 namespace internal {
55 
56 // Returns a Boolean value indicating whether the caller is currently
57 // executing in the context of the death test child process.  Tools such as
58 // Valgrind heap checkers may need this to modify their behavior in death
59 // tests.  IMPORTANT: This is an internal utility.  Using it may break the
60 // implementation of death tests.  User code MUST NOT use it.
61 GTEST_API_ bool InDeathTestChild();
62 
63 }  // namespace internal
64 
65 // The following macros are useful for writing death tests.
66 
67 // Here's what happens when an ASSERT_DEATH* or EXPECT_DEATH* is
68 // executed:
69 //
70 //   1. It generates a warning if there is more than one active
71 //   thread.  This is because it's safe to fork() or clone() only
72 //   when there is a single thread.
73 //
74 //   2. The parent process clone()s a sub-process and runs the death
75 //   test in it; the sub-process exits with code 0 at the end of the
76 //   death test, if it hasn't exited already.
77 //
78 //   3. The parent process waits for the sub-process to terminate.
79 //
80 //   4. The parent process checks the exit code and error message of
81 //   the sub-process.
82 //
83 // Examples:
84 //
85 //   ASSERT_DEATH(server.SendMessage(56, "Hello"), "Invalid port number");
86 //   for (int i = 0; i < 5; i++) {
87 //     EXPECT_DEATH(server.ProcessRequest(i),
88 //                  "Invalid request .* in ProcessRequest()")
89 //                  << "Failed to die on request " << i;
90 //   }
91 //
92 //   ASSERT_EXIT(server.ExitNow(), ::testing::ExitedWithCode(0), "Exiting");
93 //
94 //   bool KilledBySIGHUP(int exit_code) {
95 //     return WIFSIGNALED(exit_code) && WTERMSIG(exit_code) == SIGHUP;
96 //   }
97 //
98 //   ASSERT_EXIT(client.HangUpServer(), KilledBySIGHUP, "Hanging up!");
99 //
100 // On the regular expressions used in death tests:
101 //
102 //   On POSIX-compliant systems (*nix), we use the <regex.h> library,
103 //   which uses the POSIX extended regex syntax.
104 //
105 //   On other platforms (e.g. Windows), we only support a simple regex
106 //   syntax implemented as part of Google Test.  This limited
107 //   implementation should be enough most of the time when writing
108 //   death tests; though it lacks many features you can find in PCRE
109 //   or POSIX extended regex syntax.  For example, we don't support
110 //   union ("x|y"), grouping ("(xy)"), brackets ("[xy]"), and
111 //   repetition count ("x{5,7}"), among others.
112 //
113 //   Below is the syntax that we do support.  We chose it to be a
114 //   subset of both PCRE and POSIX extended regex, so it's easy to
115 //   learn wherever you come from.  In the following: 'A' denotes a
116 //   literal character, period (.), or a single \\ escape sequence;
117 //   'x' and 'y' denote regular expressions; 'm' and 'n' are for
118 //   natural numbers.
119 //
120 //     c     matches any literal character c
121 //     \\d   matches any decimal digit
122 //     \\D   matches any character that's not a decimal digit
123 //     \\f   matches \f
124 //     \\n   matches \n
125 //     \\r   matches \r
126 //     \\s   matches any ASCII whitespace, including \n
127 //     \\S   matches any character that's not a whitespace
128 //     \\t   matches \t
129 //     \\v   matches \v
130 //     \\w   matches any letter, _, or decimal digit
131 //     \\W   matches any character that \\w doesn't match
132 //     \\c   matches any literal character c, which must be a punctuation
133 //     .     matches any single character except \n
134 //     A?    matches 0 or 1 occurrences of A
135 //     A*    matches 0 or many occurrences of A
136 //     A+    matches 1 or many occurrences of A
137 //     ^     matches the beginning of a string (not that of each line)
138 //     $     matches the end of a string (not that of each line)
139 //     xy    matches x followed by y
140 //
141 //   If you accidentally use PCRE or POSIX extended regex features
142 //   not implemented by us, you will get a run-time failure.  In that
143 //   case, please try to rewrite your regular expression within the
144 //   above syntax.
145 //
146 //   This implementation is *not* meant to be as highly tuned or robust
147 //   as a compiled regex library, but should perform well enough for a
148 //   death test, which already incurs significant overhead by launching
149 //   a child process.
150 //
151 // Known caveats:
152 //
153 //   A "threadsafe" style death test obtains the path to the test
154 //   program from argv[0] and re-executes it in the sub-process.  For
155 //   simplicity, the current implementation doesn't search the PATH
156 //   when launching the sub-process.  This means that the user must
157 //   invoke the test program via a path that contains at least one
158 //   path separator (e.g. path/to/foo_test and
159 //   /absolute/path/to/bar_test are fine, but foo_test is not).  This
160 //   is rarely a problem as people usually don't put the test binary
161 //   directory in PATH.
162 //
163 // TODO(wan@google.com): make thread-safe death tests search the PATH.
164 
165 // Asserts that a given statement causes the program to exit, with an
166 // integer exit status that satisfies predicate, and emitting error output
167 // that matches regex.
168 # define ASSERT_EXIT(statement, predicate, regex) \
169     GTEST_DEATH_TEST_(statement, predicate, regex, GTEST_FATAL_FAILURE_)
170 
171 // Like ASSERT_EXIT, but continues on to successive tests in the
172 // test case, if any:
173 # define EXPECT_EXIT(statement, predicate, regex) \
174     GTEST_DEATH_TEST_(statement, predicate, regex, GTEST_NONFATAL_FAILURE_)
175 
176 // Asserts that a given statement causes the program to exit, either by
177 // explicitly exiting with a nonzero exit code or being killed by a
178 // signal, and emitting error output that matches regex.
179 # define ASSERT_DEATH(statement, regex) \
180     ASSERT_EXIT(statement, ::testing::internal::ExitedUnsuccessfully, regex)
181 
182 // Like ASSERT_DEATH, but continues on to successive tests in the
183 // test case, if any:
184 # define EXPECT_DEATH(statement, regex) \
185     EXPECT_EXIT(statement, ::testing::internal::ExitedUnsuccessfully, regex)
186 
187 // Two predicate classes that can be used in {ASSERT,EXPECT}_EXIT*:
188 
189 // Tests that an exit code describes a normal exit with a given exit code.
190 class GTEST_API_ ExitedWithCode {
191  public:
192   explicit ExitedWithCode(int exit_code);
193   bool operator()(int exit_status) const;
194  private:
195   // No implementation - assignment is unsupported.
196   void operator=(const ExitedWithCode& other);
197 
198   const int exit_code_;
199 };
200 
201 # if !GTEST_OS_WINDOWS
202 // Tests that an exit code describes an exit due to termination by a
203 // given signal.
204 class GTEST_API_ KilledBySignal {
205  public:
206   explicit KilledBySignal(int signum);
207   bool operator()(int exit_status) const;
208  private:
209   const int signum_;
210 };
211 # endif  // !GTEST_OS_WINDOWS
212 
213 // EXPECT_DEBUG_DEATH asserts that the given statements die in debug mode.
214 // The death testing framework causes this to have interesting semantics,
215 // since the sideeffects of the call are only visible in opt mode, and not
216 // in debug mode.
217 //
218 // In practice, this can be used to test functions that utilize the
219 // LOG(DFATAL) macro using the following style:
220 //
221 // int DieInDebugOr12(int* sideeffect) {
222 //   if (sideeffect) {
223 //     *sideeffect = 12;
224 //   }
225 //   LOG(DFATAL) << "death";
226 //   return 12;
227 // }
228 //
229 // TEST(TestCase, TestDieOr12WorksInDgbAndOpt) {
230 //   int sideeffect = 0;
231 //   // Only asserts in dbg.
232 //   EXPECT_DEBUG_DEATH(DieInDebugOr12(&sideeffect), "death");
233 //
234 // #ifdef NDEBUG
235 //   // opt-mode has sideeffect visible.
236 //   EXPECT_EQ(12, sideeffect);
237 // #else
238 //   // dbg-mode no visible sideeffect.
239 //   EXPECT_EQ(0, sideeffect);
240 // #endif
241 // }
242 //
243 // This will assert that DieInDebugReturn12InOpt() crashes in debug
244 // mode, usually due to a DCHECK or LOG(DFATAL), but returns the
245 // appropriate fallback value (12 in this case) in opt mode. If you
246 // need to test that a function has appropriate side-effects in opt
247 // mode, include assertions against the side-effects.  A general
248 // pattern for this is:
249 //
250 // EXPECT_DEBUG_DEATH({
251 //   // Side-effects here will have an effect after this statement in
252 //   // opt mode, but none in debug mode.
253 //   EXPECT_EQ(12, DieInDebugOr12(&sideeffect));
254 // }, "death");
255 //
256 # ifdef NDEBUG
257 
258 #  define EXPECT_DEBUG_DEATH(statement, regex) \
259   GTEST_EXECUTE_STATEMENT_(statement, regex)
260 
261 #  define ASSERT_DEBUG_DEATH(statement, regex) \
262   GTEST_EXECUTE_STATEMENT_(statement, regex)
263 
264 # else
265 
266 #  define EXPECT_DEBUG_DEATH(statement, regex) \
267   EXPECT_DEATH(statement, regex)
268 
269 #  define ASSERT_DEBUG_DEATH(statement, regex) \
270   ASSERT_DEATH(statement, regex)
271 
272 # endif  // NDEBUG for EXPECT_DEBUG_DEATH
273 #endif  // GTEST_HAS_DEATH_TEST
274 
275 // EXPECT_DEATH_IF_SUPPORTED(statement, regex) and
276 // ASSERT_DEATH_IF_SUPPORTED(statement, regex) expand to real death tests if
277 // death tests are supported; otherwise they just issue a warning.  This is
278 // useful when you are combining death test assertions with normal test
279 // assertions in one test.
280 #if GTEST_HAS_DEATH_TEST
281 # define EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
282     EXPECT_DEATH(statement, regex)
283 # define ASSERT_DEATH_IF_SUPPORTED(statement, regex) \
284     ASSERT_DEATH(statement, regex)
285 #else
286 # define EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
287     GTEST_UNSUPPORTED_DEATH_TEST_(statement, regex, )
288 # define ASSERT_DEATH_IF_SUPPORTED(statement, regex) \
289     GTEST_UNSUPPORTED_DEATH_TEST_(statement, regex, return)
290 #endif
291 
292 }  // namespace testing
293 
294 #endif  // GTEST_INCLUDE_GTEST_GTEST_DEATH_TEST_H_
295