linux/tests/unit_tests.h

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef SANDBOX_LINUX_TESTS_UNIT_TESTS_H__
#define SANDBOX_LINUX_TESTS_UNIT_TESTS_H__

#include "base/basictypes.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace sandbox {

// While it is perfectly OK for a complex test to provide its own DeathCheck
// function. Most death tests have very simple requirements. These tests should
// use one of the predefined DEATH_XXX macros as an argument to
// SANDBOX_DEATH_TEST(). You can check for a (sub-)string in the output of the
// test, for a particular exit code, or for a particular death signal.
// NOTE: If you do decide to write your own DeathCheck, make sure to use
//       gtests's ASSERT_XXX() macros instead of SANDBOX_ASSERT(). See
//       unit_tests.cc for examples.
#define DEATH_SUCCESS()     sandbox::UnitTests::DeathSuccess, NULL
#define DEATH_MESSAGE(msg)  sandbox::UnitTests::DeathMessage,                 \
                            static_cast<const void *>(                        \
                                static_cast<const char *>(msg))
#define DEATH_EXIT_CODE(rc) sandbox::UnitTests::DeathExitCode,                \
                            reinterpret_cast<void *>(static_cast<intptr_t>(rc))
#define DEATH_BY_SIGNAL(s)  sandbox::UnitTests::DeathExitCode,                \
                            reinterpret_cast<void *>(static_cast<intptr_t>(s))

// A SANDBOX_DEATH_TEST is just like a SANDBOX_TEST (see below), but it assumes
// that the test actually dies. The death test only passes if the death occurs
// in the expected fashion, as specified by "death" and "death_aux". These two
// parameters are typically set to one of the DEATH_XXX() macros.
#define SANDBOX_DEATH_TEST(test_case_name, test_name, death)                  \
  void TEST_##test_name(void *);                                              \
  TEST(test_case_name, test_name) {                                           \
    sandbox::UnitTests::RunTestInProcess(TEST_##test_name, NULL, death);      \
  }                                                                           \
  void TEST_##test_name(void *)

// Define a new test case that runs inside of a GTest death test. This is
// necessary, as most of our tests by definition make global and irreversible
// changes to the system (i.e. they install a sandbox). GTest provides death
// tests as a tool to isolate global changes from the rest of the tests.
#define SANDBOX_TEST(test_case_name, test_name)                               \
  SANDBOX_DEATH_TEST(test_case_name, test_name, DEATH_SUCCESS())

// Simple assertion macro that is compatible with running inside of a death
// test. We unfortunately cannot use any of the GTest macros.
#define SANDBOX_STR(x) #x
#define SANDBOX_ASSERT(expr)                                                  \
  ((expr)                                                                     \
   ? static_cast<void>(0)                                                     \
   : sandbox::UnitTests::AssertionFailure(SANDBOX_STR(expr),                  \
                                          __FILE__, __LINE__))

class UnitTests {
 public:
  typedef void (*Test)(void *);
  typedef void (*DeathCheck)(int status, const std::string& msg,
                             const void *aux);

  // Runs a test inside a short-lived process. Do not call this function
  // directly. It is automatically invoked by SANDBOX_TEST(). Most sandboxing
  // functions make global irreversible changes to the execution environment
  // and must therefore execute in their own isolated process.
  static void RunTestInProcess(Test test, void *arg, DeathCheck death,
                               const void *death_aux);

  // Report a useful error message and terminate the current SANDBOX_TEST().
  // Calling this function from outside a SANDBOX_TEST() is unlikely to do
  // anything useful.
  static void AssertionFailure(const char *expr, const char *file, int line);

  // Sometimes we determine at run-time that a test should be disabled.
  // Call this method if we want to return from a test and completely
  // ignore its results.
  // You should not call this method, if the test already ran any test-relevant
  // code. Most notably, you should not call it, you already wrote any messages
  // to stderr.
  static void IgnoreThisTest();

  // A DeathCheck method that verifies that the test completed succcessfully.
  // This is the default test mode for SANDBOX_TEST(). The "aux" parameter
  // of this DeathCheck is unused (and thus unnamed)
  static void DeathSuccess(int status, const std::string& msg, const void *);

  // A DeathCheck method that verifies that the test completed with error
  // code "1" and printed a message containing a particular substring. The
  // "aux" pointer should point to a C-string containing the expected error
  // message. This method is useful for checking assertion failures such as
  // in SANDBOX_ASSERT() and/or SANDBOX_DIE().
  static void DeathMessage(int status, const std::string& msg,
                           const void *aux);

  // A DeathCheck method that verifies that the test completed with a
  // particular exit code. If the test output any messages to stderr, they are
  // silently ignored. The expected exit code should be passed in by
  // casting the its "int" value to a "void *", which is then used for "aux".
  static void DeathExitCode(int status, const std::string& msg,
                            const void *aux);

  // A DeathCheck method that verifies that the test was terminated by a
  // particular signal. If the test output any messages to stderr, they are
  // silently ignore. The expected signal number should be passed in by
  // casting the its "int" value to a "void *", which is then used for "aux".
  static void DeathBySignal(int status, const std::string& msg,
                            const void *aux);

 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(UnitTests);
};

}  // namespace

#endif  // SANDBOX_LINUX_TESTS_UNIT_TESTS_H__