xref: /freebsd/contrib/googletest/googletest/include/gtest/gtest-death-test.h (revision 5ca8c28cd8c725b81781201cfdb5f9969396f934)
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29 
30 // The Google C++ Testing and Mocking Framework (Google Test)
31 //
32 // This header file defines the public API for death tests.  It is
33 // #included by gtest.h so a user doesn't need to include this
34 // directly.
35 
36 // IWYU pragma: private, include "gtest/gtest.h"
37 // IWYU pragma: friend gtest/.*
38 // IWYU pragma: friend gmock/.*
39 
40 #ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_DEATH_TEST_H_
41 #define GOOGLETEST_INCLUDE_GTEST_GTEST_DEATH_TEST_H_
42 
43 #include "gtest/internal/gtest-death-test-internal.h"
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 namespace testing {
53 
54 #ifdef GTEST_HAS_DEATH_TEST
55 
56 namespace internal {
57 
58 // Returns a Boolean value indicating whether the caller is currently
59 // executing in the context of the death test child process.  Tools such as
60 // Valgrind heap checkers may need this to modify their behavior in death
61 // tests.  IMPORTANT: This is an internal utility.  Using it may break the
62 // implementation of death tests.  User code MUST NOT use it.
63 GTEST_API_ bool InDeathTestChild();
64 
65 }  // namespace internal
66 
67 // The following macros are useful for writing death tests.
68 
69 // Here's what happens when an ASSERT_DEATH* or EXPECT_DEATH* is
70 // executed:
71 //
72 //   1. It generates a warning if there is more than one active
73 //   thread.  This is because it's safe to fork() or clone() only
74 //   when there is a single thread.
75 //
76 //   2. The parent process clone()s a sub-process and runs the death
77 //   test in it; the sub-process exits with code 0 at the end of the
78 //   death test, if it hasn't exited already.
79 //
80 //   3. The parent process waits for the sub-process to terminate.
81 //
82 //   4. The parent process checks the exit code and error message of
83 //   the sub-process.
84 //
85 // Examples:
86 //
87 //   ASSERT_DEATH(server.SendMessage(56, "Hello"), "Invalid port number");
88 //   for (int i = 0; i < 5; i++) {
89 //     EXPECT_DEATH(server.ProcessRequest(i),
90 //                  "Invalid request .* in ProcessRequest()")
91 //                  << "Failed to die on request " << i;
92 //   }
93 //
94 //   ASSERT_EXIT(server.ExitNow(), ::testing::ExitedWithCode(0), "Exiting");
95 //
96 //   bool KilledBySIGHUP(int exit_code) {
97 //     return WIFSIGNALED(exit_code) && WTERMSIG(exit_code) == SIGHUP;
98 //   }
99 //
100 //   ASSERT_EXIT(client.HangUpServer(), KilledBySIGHUP, "Hanging up!");
101 //
102 // The final parameter to each of these macros is a matcher applied to any data
103 // the sub-process wrote to stderr.  For compatibility with existing tests, a
104 // bare string is interpreted as a regular expression matcher.
105 //
106 // On the regular expressions used in death tests:
107 //
108 //   On POSIX-compliant systems (*nix), we use the <regex.h> library,
109 //   which uses the POSIX extended regex syntax.
110 //
111 //   On other platforms (e.g. Windows or Mac), we only support a simple regex
112 //   syntax implemented as part of Google Test.  This limited
113 //   implementation should be enough most of the time when writing
114 //   death tests; though it lacks many features you can find in PCRE
115 //   or POSIX extended regex syntax.  For example, we don't support
116 //   union ("x|y"), grouping ("(xy)"), brackets ("[xy]"), and
117 //   repetition count ("x{5,7}"), among others.
118 //
119 //   Below is the syntax that we do support.  We chose it to be a
120 //   subset of both PCRE and POSIX extended regex, so it's easy to
121 //   learn wherever you come from.  In the following: 'A' denotes a
122 //   literal character, period (.), or a single \\ escape sequence;
123 //   'x' and 'y' denote regular expressions; 'm' and 'n' are for
124 //   natural numbers.
125 //
126 //     c     matches any literal character c
127 //     \\d   matches any decimal digit
128 //     \\D   matches any character that's not a decimal digit
129 //     \\f   matches \f
130 //     \\n   matches \n
131 //     \\r   matches \r
132 //     \\s   matches any ASCII whitespace, including \n
133 //     \\S   matches any character that's not a whitespace
134 //     \\t   matches \t
135 //     \\v   matches \v
136 //     \\w   matches any letter, _, or decimal digit
137 //     \\W   matches any character that \\w doesn't match
138 //     \\c   matches any literal character c, which must be a punctuation
139 //     .     matches any single character except \n
140 //     A?    matches 0 or 1 occurrences of A
141 //     A*    matches 0 or many occurrences of A
142 //     A+    matches 1 or many occurrences of A
143 //     ^     matches the beginning of a string (not that of each line)
144 //     $     matches the end of a string (not that of each line)
145 //     xy    matches x followed by y
146 //
147 //   If you accidentally use PCRE or POSIX extended regex features
148 //   not implemented by us, you will get a run-time failure.  In that
149 //   case, please try to rewrite your regular expression within the
150 //   above syntax.
151 //
152 //   This implementation is *not* meant to be as highly tuned or robust
153 //   as a compiled regex library, but should perform well enough for a
154 //   death test, which already incurs significant overhead by launching
155 //   a child process.
156 //
157 // Known caveats:
158 //
159 //   A "threadsafe" style death test obtains the path to the test
160 //   program from argv[0] and re-executes it in the sub-process.  For
161 //   simplicity, the current implementation doesn't search the PATH
162 //   when launching the sub-process.  This means that the user must
163 //   invoke the test program via a path that contains at least one
164 //   path separator (e.g. path/to/foo_test and
165 //   /absolute/path/to/bar_test are fine, but foo_test is not).  This
166 //   is rarely a problem as people usually don't put the test binary
167 //   directory in PATH.
168 //
169 
170 // Asserts that a given `statement` causes the program to exit, with an
171 // integer exit status that satisfies `predicate`, and emitting error output
172 // that matches `matcher`.
173 #define ASSERT_EXIT(statement, predicate, matcher) \
174   GTEST_DEATH_TEST_(statement, predicate, matcher, GTEST_FATAL_FAILURE_)
175 
176 // Like `ASSERT_EXIT`, but continues on to successive tests in the
177 // test suite, if any:
178 #define EXPECT_EXIT(statement, predicate, matcher) \
179   GTEST_DEATH_TEST_(statement, predicate, matcher, GTEST_NONFATAL_FAILURE_)
180 
181 // Asserts that a given `statement` causes the program to exit, either by
182 // explicitly exiting with a nonzero exit code or being killed by a
183 // signal, and emitting error output that matches `matcher`.
184 #define ASSERT_DEATH(statement, matcher) \
185   ASSERT_EXIT(statement, ::testing::internal::ExitedUnsuccessfully, matcher)
186 
187 // Like `ASSERT_DEATH`, but continues on to successive tests in the
188 // test suite, if any:
189 #define EXPECT_DEATH(statement, matcher) \
190   EXPECT_EXIT(statement, ::testing::internal::ExitedUnsuccessfully, matcher)
191 
192 // Two predicate classes that can be used in {ASSERT,EXPECT}_EXIT*:
193 
194 // Tests that an exit code describes a normal exit with a given exit code.
195 class GTEST_API_ ExitedWithCode {
196  public:
197   explicit ExitedWithCode(int exit_code);
198   ExitedWithCode(const ExitedWithCode&) = default;
199   void operator=(const ExitedWithCode& other) = delete;
200   bool operator()(int exit_status) const;
201 
202  private:
203   const int exit_code_;
204 };
205 
206 #if !defined(GTEST_OS_WINDOWS) && !defined(GTEST_OS_FUCHSIA)
207 // Tests that an exit code describes an exit due to termination by a
208 // given signal.
209 class GTEST_API_ KilledBySignal {
210  public:
211   explicit KilledBySignal(int signum);
212   bool operator()(int exit_status) const;
213 
214  private:
215   const int signum_;
216 };
217 #endif  // !GTEST_OS_WINDOWS
218 
219 // EXPECT_DEBUG_DEATH asserts that the given statements die in debug mode.
220 // The death testing framework causes this to have interesting semantics,
221 // since the sideeffects of the call are only visible in opt mode, and not
222 // in debug mode.
223 //
224 // In practice, this can be used to test functions that utilize the
225 // LOG(DFATAL) macro using the following style:
226 //
227 // int DieInDebugOr12(int* sideeffect) {
228 //   if (sideeffect) {
229 //     *sideeffect = 12;
230 //   }
231 //   LOG(DFATAL) << "death";
232 //   return 12;
233 // }
234 //
235 // TEST(TestSuite, TestDieOr12WorksInDgbAndOpt) {
236 //   int sideeffect = 0;
237 //   // Only asserts in dbg.
238 //   EXPECT_DEBUG_DEATH(DieInDebugOr12(&sideeffect), "death");
239 //
240 // #ifdef NDEBUG
241 //   // opt-mode has sideeffect visible.
242 //   EXPECT_EQ(12, sideeffect);
243 // #else
244 //   // dbg-mode no visible sideeffect.
245 //   EXPECT_EQ(0, sideeffect);
246 // #endif
247 // }
248 //
249 // This will assert that DieInDebugReturn12InOpt() crashes in debug
250 // mode, usually due to a DCHECK or LOG(DFATAL), but returns the
251 // appropriate fallback value (12 in this case) in opt mode. If you
252 // need to test that a function has appropriate side-effects in opt
253 // mode, include assertions against the side-effects.  A general
254 // pattern for this is:
255 //
256 // EXPECT_DEBUG_DEATH({
257 //   // Side-effects here will have an effect after this statement in
258 //   // opt mode, but none in debug mode.
259 //   EXPECT_EQ(12, DieInDebugOr12(&sideeffect));
260 // }, "death");
261 //
262 #ifdef NDEBUG
263 
264 #define EXPECT_DEBUG_DEATH(statement, regex) \
265   GTEST_EXECUTE_STATEMENT_(statement, regex)
266 
267 #define ASSERT_DEBUG_DEATH(statement, regex) \
268   GTEST_EXECUTE_STATEMENT_(statement, regex)
269 
270 #else
271 
272 #define EXPECT_DEBUG_DEATH(statement, regex) EXPECT_DEATH(statement, regex)
273 
274 #define ASSERT_DEBUG_DEATH(statement, regex) ASSERT_DEATH(statement, regex)
275 
276 #endif  // NDEBUG for EXPECT_DEBUG_DEATH
277 #endif  // GTEST_HAS_DEATH_TEST
278 
279 // This macro is used for implementing macros such as
280 // EXPECT_DEATH_IF_SUPPORTED and ASSERT_DEATH_IF_SUPPORTED on systems where
281 // death tests are not supported. Those macros must compile on such systems
282 // if and only if EXPECT_DEATH and ASSERT_DEATH compile with the same parameters
283 // on systems that support death tests. This allows one to write such a macro on
284 // a system that does not support death tests and be sure that it will compile
285 // on a death-test supporting system. It is exposed publicly so that systems
286 // that have death-tests with stricter requirements than GTEST_HAS_DEATH_TEST
287 // can write their own equivalent of EXPECT_DEATH_IF_SUPPORTED and
288 // ASSERT_DEATH_IF_SUPPORTED.
289 //
290 // Parameters:
291 //   statement -  A statement that a macro such as EXPECT_DEATH would test
292 //                for program termination. This macro has to make sure this
293 //                statement is compiled but not executed, to ensure that
294 //                EXPECT_DEATH_IF_SUPPORTED compiles with a certain
295 //                parameter if and only if EXPECT_DEATH compiles with it.
296 //   regex_or_matcher -  A regex that a macro such as EXPECT_DEATH would use
297 //                to test the output of statement.  This parameter has to be
298 //                compiled but not evaluated by this macro, to ensure that
299 //                this macro only accepts expressions that a macro such as
300 //                EXPECT_DEATH would accept.
301 //   terminator - Must be an empty statement for EXPECT_DEATH_IF_SUPPORTED
302 //                and a return statement for ASSERT_DEATH_IF_SUPPORTED.
303 //                This ensures that ASSERT_DEATH_IF_SUPPORTED will not
304 //                compile inside functions where ASSERT_DEATH doesn't
305 //                compile.
306 //
307 //  The branch that has an always false condition is used to ensure that
308 //  statement and regex are compiled (and thus syntactically correct) but
309 //  never executed. The unreachable code macro protects the terminator
310 //  statement from generating an 'unreachable code' warning in case
311 //  statement unconditionally returns or throws. The Message constructor at
312 //  the end allows the syntax of streaming additional messages into the
313 //  macro, for compilational compatibility with EXPECT_DEATH/ASSERT_DEATH.
314 #define GTEST_UNSUPPORTED_DEATH_TEST(statement, regex_or_matcher, terminator)  \
315   GTEST_AMBIGUOUS_ELSE_BLOCKER_                                                \
316   if (::testing::internal::AlwaysTrue()) {                                     \
317     GTEST_LOG_(WARNING) << "Death tests are not supported on this platform.\n" \
318                         << "Statement '" #statement "' cannot be verified.";   \
319   } else if (::testing::internal::AlwaysFalse()) {                             \
320     ::testing::internal::MakeDeathTestMatcher(regex_or_matcher);               \
321     GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement);                 \
322     terminator;                                                                \
323   } else                                                                       \
324     ::testing::Message()
325 
326 // EXPECT_DEATH_IF_SUPPORTED(statement, regex) and
327 // ASSERT_DEATH_IF_SUPPORTED(statement, regex) expand to real death tests if
328 // death tests are supported; otherwise they just issue a warning.  This is
329 // useful when you are combining death test assertions with normal test
330 // assertions in one test.
331 #ifdef GTEST_HAS_DEATH_TEST
332 #define EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
333   EXPECT_DEATH(statement, regex)
334 #define ASSERT_DEATH_IF_SUPPORTED(statement, regex) \
335   ASSERT_DEATH(statement, regex)
336 #else
337 #define EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
338   GTEST_UNSUPPORTED_DEATH_TEST(statement, regex, )
339 #define ASSERT_DEATH_IF_SUPPORTED(statement, regex) \
340   GTEST_UNSUPPORTED_DEATH_TEST(statement, regex, return)
341 #endif
342 
343 }  // namespace testing
344 
345 #endif  // GOOGLETEST_INCLUDE_GTEST_GTEST_DEATH_TEST_H_
346