gtest-death-test-internal.h #1

// Copyright 2005, Google Inc.
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//
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// Authors: wan@google.com (Zhanyong Wan), eefacm@gmail.com (Sean Mcafee)
//
// The Google C++ Testing Framework (Google Test)
//
// This header file defines internal utilities needed for implementing
// death tests.  They are subject to change without notice.

#ifndef GTEST_INCLUDE_GTEST_INTERNAL_GTEST_DEATH_TEST_INTERNAL_H_
#define GTEST_INCLUDE_GTEST_INTERNAL_GTEST_DEATH_TEST_INTERNAL_H_

#include "gtest/internal/gtest-internal.h"

#include <stdio.h>

namespace testing {
namespace internal {

GTEST_DECLARE_string_(internal_run_death_test);

// Names of the flags (needed for parsing Google Test flags).
const char kDeathTestStyleFlag[] = "death_test_style";
const char kDeathTestUseFork[] = "death_test_use_fork";
const char kInternalRunDeathTestFlag[] = "internal_run_death_test";

#if GTEST_HAS_DEATH_TEST

// DeathTest is a class that hides much of the complexity of the
// GTEST_DEATH_TEST_ macro.  It is abstract; its static Create method
// returns a concrete class that depends on the prevailing death test
// style, as defined by the --gtest_death_test_style and/or
// --gtest_internal_run_death_test flags.

// In describing the results of death tests, these terms are used with
// the corresponding definitions:
//
// exit status:  The integer exit information in the format specified
//               by wait(2)
// exit code:    The integer code passed to exit(3), _exit(2), or
//               returned from main()
class GTEST_API_ DeathTest {
 public:
  // Create returns false if there was an error determining the
  // appropriate action to take for the current death test; for example,
  // if the gtest_death_test_style flag is set to an invalid value.
  // The LastMessage method will return a more detailed message in that
  // case.  Otherwise, the DeathTest pointer pointed to by the "test"
  // argument is set.  If the death test should be skipped, the pointer
  // is set to NULL; otherwise, it is set to the address of a new concrete
  // DeathTest object that controls the execution of the current test.
  static bool Create(const char* statement, const RE* regex,
                     const char* file, int line, DeathTest** test);
  DeathTest();
  virtual ~DeathTest() { }

  // A helper class that aborts a death test when it's deleted.
  class ReturnSentinel {
   public:
    explicit ReturnSentinel(DeathTest* test) : test_(test) { }
    ~ReturnSentinel() { test_->Abort(TEST_ENCOUNTERED_RETURN_STATEMENT); }
   private:
    DeathTest* const test_;
    GTEST_DISALLOW_COPY_AND_ASSIGN_(ReturnSentinel);
  } GTEST_ATTRIBUTE_UNUSED_;

  // An enumeration of possible roles that may be taken when a death
  // test is encountered.  EXECUTE means that the death test logic should
  // be executed immediately.  OVERSEE means that the program should prepare
  // the appropriate environment for a child process to execute the death
  // test, then wait for it to complete.
  enum TestRole { OVERSEE_TEST, EXECUTE_TEST };

  // An enumeration of the three reasons that a test might be aborted.
  enum AbortReason {
    TEST_ENCOUNTERED_RETURN_STATEMENT,
    TEST_THREW_EXCEPTION,
    TEST_DID_NOT_DIE
  };

  // Assumes one of the above roles.
  virtual TestRole AssumeRole() = 0;

  // Waits for the death test to finish and returns its status.
  virtual int Wait() = 0;

  // Returns true if the death test passed; that is, the test process
  // exited during the test, its exit status matches a user-supplied
  // predicate, and its stderr output matches a user-supplied regular
  // expression.
  // The user-supplied predicate may be a macro expression rather
  // than a function pointer or functor, or else Wait and Passed could
  // be combined.
  virtual bool Passed(bool exit_status_ok) = 0;

  // Signals that the death test did not die as expected.
  virtual void Abort(AbortReason reason) = 0;

  // Returns a human-readable outcome message regarding the outcome of
  // the last death test.
  static const char* LastMessage();

  static void set_last_death_test_message(const std::string& message);

 private:
  // A string containing a description of the outcome of the last death test.
  static std::string last_death_test_message_;

  GTEST_DISALLOW_COPY_AND_ASSIGN_(DeathTest);
};

// Factory interface for death tests.  May be mocked out for testing.
class DeathTestFactory {
 public:
  virtual ~DeathTestFactory() { }
  virtual bool Create(const char* statement, const RE* regex,
                      const char* file, int line, DeathTest** test) = 0;
};

// A concrete DeathTestFactory implementation for normal use.
class DefaultDeathTestFactory : public DeathTestFactory {
 public:
  virtual bool Create(const char* statement, const RE* regex,
                      const char* file, int line, DeathTest** test);
};

// Returns true if exit_status describes a process that was terminated
// by a signal, or exited normally with a nonzero exit code.
GTEST_API_ bool ExitedUnsuccessfully(int exit_status);

// Traps C++ exceptions escaping statement and reports them as test
// failures. Note that trapping SEH exceptions is not implemented here.
# if GTEST_HAS_EXCEPTIONS
#  define GTEST_EXECUTE_DEATH_TEST_STATEMENT_(statement, death_test) \
  try { \
    GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
  } catch (const ::std::exception& gtest_exception) { \
    fprintf(\
        stderr, \
        "\n%s: Caught std::exception-derived exception escaping the " \
        "death test statement. Exception message: %s\n", \
        ::testing::internal::FormatFileLocation(__FILE__, __LINE__).c_str(), \
        gtest_exception.what()); \
    fflush(stderr); \
    death_test->Abort(::testing::internal::DeathTest::TEST_THREW_EXCEPTION); \
  } catch (...) { \
    death_test->Abort(::testing::internal::DeathTest::TEST_THREW_EXCEPTION); \
  }

# else
#  define GTEST_EXECUTE_DEATH_TEST_STATEMENT_(statement, death_test) \
  GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement)

# endif

// This macro is for implementing ASSERT_DEATH*, EXPECT_DEATH*,
// ASSERT_EXIT*, and EXPECT_EXIT*.
# define GTEST_DEATH_TEST_(statement, predicate, regex, fail) \
  GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
  if (::testing::internal::AlwaysTrue()) { \
    const ::testing::internal::RE& gtest_regex = (regex); \
    ::testing::internal::DeathTest* gtest_dt; \
    if (!::testing::internal::DeathTest::Create(#statement, &gtest_regex, \
        __FILE__, __LINE__, &gtest_dt)) { \
      goto GTEST_CONCAT_TOKEN_(gtest_label_, __LINE__); \
    } \
    if (gtest_dt != NULL) { \
      ::testing::internal::scoped_ptr< ::testing::internal::DeathTest> \
          gtest_dt_ptr(gtest_dt); \
      switch (gtest_dt->AssumeRole()) { \
        case ::testing::internal::DeathTest::OVERSEE_TEST: \
          if (!gtest_dt->Passed(predicate(gtest_dt->Wait()))) { \
            goto GTEST_CONCAT_TOKEN_(gtest_label_, __LINE__); \
          } \
          break; \
        case ::testing::internal::DeathTest::EXECUTE_TEST: { \
          ::testing::internal::DeathTest::ReturnSentinel \
              gtest_sentinel(gtest_dt); \
          GTEST_EXECUTE_DEATH_TEST_STATEMENT_(statement, gtest_dt); \
          gtest_dt->Abort(::testing::internal::DeathTest::TEST_DID_NOT_DIE); \
          break; \
        } \
        default: \
          break; \
      } \
    } \
  } else \
    GTEST_CONCAT_TOKEN_(gtest_label_, __LINE__): \
      fail(::testing::internal::DeathTest::LastMessage())
// The symbol "fail" here expands to something into which a message
// can be streamed.

// This macro is for implementing ASSERT/EXPECT_DEBUG_DEATH when compiled in
// NDEBUG mode. In this case we need the statements to be executed, the regex is
// ignored, and the macro must accept a streamed message even though the message
// is never printed.
# define GTEST_EXECUTE_STATEMENT_(statement, regex) \
  GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
  if (::testing::internal::AlwaysTrue()) { \
     GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
  } else \
    ::testing::Message()

// A class representing the parsed contents of the
// --gtest_internal_run_death_test flag, as it existed when
// RUN_ALL_TESTS was called.
class InternalRunDeathTestFlag {
 public:
  InternalRunDeathTestFlag(const std::string& a_file,
                           int a_line,
                           int an_index,
                           int a_write_fd)
      : file_(a_file), line_(a_line), index_(an_index),
        write_fd_(a_write_fd) {}

  ~InternalRunDeathTestFlag() {
    if (write_fd_ >= 0)
      posix::Close(write_fd_);
  }

  const std::string& file() const { return file_; }
  int line() const { return line_; }
  int index() const { return index_; }
  int write_fd() const { return write_fd_; }

 private:
  std::string file_;
  int line_;
  int index_;
  int write_fd_;

  GTEST_DISALLOW_COPY_AND_ASSIGN_(InternalRunDeathTestFlag);
};

// Returns a newly created InternalRunDeathTestFlag object with fields
// initialized from the GTEST_FLAG(internal_run_death_test) flag if
// the flag is specified; otherwise returns NULL.
InternalRunDeathTestFlag* ParseInternalRunDeathTestFlag();

#else  // GTEST_HAS_DEATH_TEST

// This macro is used for implementing macros such as
// EXPECT_DEATH_IF_SUPPORTED and ASSERT_DEATH_IF_SUPPORTED on systems where
// death tests are not supported. Those macros must compile on such systems
// iff EXPECT_DEATH and ASSERT_DEATH compile with the same parameters on
// systems that support death tests. This allows one to write such a macro
// on a system that does not support death tests and be sure that it will
// compile on a death-test supporting system.
//
// Parameters:
//   statement -  A statement that a macro such as EXPECT_DEATH would test
//                for program termination. This macro has to make sure this
//                statement is compiled but not executed, to ensure that
//                EXPECT_DEATH_IF_SUPPORTED compiles with a certain
//                parameter iff EXPECT_DEATH compiles with it.
//   regex     -  A regex that a macro such as EXPECT_DEATH would use to test
//                the output of statement.  This parameter has to be
//                compiled but not evaluated by this macro, to ensure that
//                this macro only accepts expressions that a macro such as
//                EXPECT_DEATH would accept.
//   terminator - Must be an empty statement for EXPECT_DEATH_IF_SUPPORTED
//                and a return statement for ASSERT_DEATH_IF_SUPPORTED.
//                This ensures that ASSERT_DEATH_IF_SUPPORTED will not
//                compile inside functions where ASSERT_DEATH doesn't
//                compile.
//
//  The branch that has an always false condition is used to ensure that
//  statement and regex are compiled (and thus syntactically correct) but
//  never executed. The unreachable code macro protects the terminator
//  statement from generating an 'unreachable code' warning in case
//  statement unconditionally returns or throws. The Message constructor at
//  the end allows the syntax of streaming additional messages into the
//  macro, for compilational compatibility with EXPECT_DEATH/ASSERT_DEATH.
# define GTEST_UNSUPPORTED_DEATH_TEST_(statement, regex, terminator) \
    GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
    if (::testing::internal::AlwaysTrue()) { \
      GTEST_LOG_(WARNING) \
          << "Death tests are not supported on this platform.\n" \
          << "Statement '" #statement "' cannot be verified."; \
    } else if (::testing::internal::AlwaysFalse()) { \
      ::testing::internal::RE::PartialMatch(".*", (regex)); \
      GTEST_SUPPRESS_UNREACHABLE_CODE_WARNING_BELOW_(statement); \
      terminator; \
    } else \
      ::testing::Message()

#endif  // GTEST_HAS_DEATH_TEST

}  // namespace internal
}  // namespace testing

#endif  // GTEST_INCLUDE_GTEST_INTERNAL_GTEST_DEATH_TEST_INTERNAL_H_