Googletest 实现简要分析
借助于 Googletest 测试框架，我们只需编写测试用例代码，并定义简单的 main() 函数，编译之后并运行即可以把我们的测试用例跑起来。(更详细的内容可参考 Googletest 入门)。但 main() 函数调用 RUN_ALL_TESTS() 时，是如何找到并运行我们编写的测试用例代码的呢？本文尝试找寻 Googletest 框架背后隐藏的这些秘密。（代码分析基于 [email protected]:google/googletest.git 的 commit 2134e3fd857d952e03ce76064fad5ac6e9036104 的版本。）
从 TEST 和 TEST_F 说起
googletest/googletest/include/gtest/gtest.h 中 TEST 和 TEST_F 两个宏的定义如下：
// Note that we call GetTestTypeId() instead of GetTypeId<
// ::testing::Test>() here to get the type ID of testing::Test. This
// is to work around a suspected linker bug when using Google Test as
// a framework on Mac OS X. The bug causes GetTypeId<
// ::testing::Test>() to return different values depending on whether
// the call is from the Google Test framework itself or from user test
// code. GetTestTypeId() is guaranteed to always return the same
// value, as it always calls GetTypeId<>() from the Google Test
// framework.
#define GTEST_TEST(test_suite_name, test_name) \
GTEST_TEST_(test_suite_name, test_name, ::testing::Test, \
::testing::internal::GetTestTypeId())
// Define this macro to 1 to omit the definition of TEST(), which
// is a generic name and clashes with some other libraries.
#if !GTEST_DONT_DEFINE_TEST
#define TEST(test_suite_name, test_name) GTEST_TEST(test_suite_name, test_name)
#endif
// Defines a test that uses a test fixture.
//
// The first parameter is the name of the test fixture class, which
// also doubles as the test suite name. The second parameter is the
// name of the test within the test suite.
//
// A test fixture class must be declared earlier. The user should put
// the test code between braces after using this macro. Example:
//
// class FooTest : public testing::Test {
// protected:
// void SetUp() override { b_.AddElement(3); }
//
// Foo a_;
// Foo b_;
// };
//
// TEST_F(FooTest, InitializesCorrectly) {
// EXPECT_TRUE(a_.StatusIsOK());
// }
//
// TEST_F(FooTest, ReturnsElementCountCorrectly) {
// EXPECT_EQ(a_.size(), 0);
// EXPECT_EQ(b_.size(), 1);
// }
//
// GOOGLETEST_CM0011 DO NOT DELETE
#define TEST_F(test_fixture, test_name)\
GTEST_TEST_(test_fixture, test_name, test_fixture, \
::testing::internal::GetTypeId())
TEST 和 TEST_F 两个宏最终都借助于 GTEST_TEST_ 宏完成其工作。
googletest/googletest/include/gtest/internal/gtest-internal.h 中 GTEST_TEST_ 宏的定义如下：
// Expands to the name of the class that implements the given test.
#define GTEST_TEST_CLASS_NAME_(test_suite_name, test_name) \
test_suite_name##_##test_name##_Test
// Helper macro for defining tests.
#define GTEST_TEST_(test_suite_name, test_name, parent_class, parent_id) \
class GTEST_TEST_CLASS_NAME_(test_suite_name, test_name) \
: public parent_class { \
public: \
GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)() {} \
\
private: \
virtual void TestBody(); \
static ::testing::TestInfo* const test_info_ GTEST_ATTRIBUTE_UNUSED_; \
GTEST_DISALLOW_COPY_AND_ASSIGN_(GTEST_TEST_CLASS_NAME_(test_suite_name, \
test_name)); \
}; \
\
::testing::TestInfo* const GTEST_TEST_CLASS_NAME_(test_suite_name, \
test_name)::test_info_ = \
::testing::internal::MakeAndRegisterTestInfo( \
#test_suite_name, #test_name, nullptr, nullptr, \
::testing::internal::CodeLocation(__FILE__, __LINE__), (parent_id), \
::testing::internal::SuiteApiResolver< \
parent_class>::GetSetUpCaseOrSuite(__FILE__, __LINE__), \
::testing::internal::SuiteApiResolver< \
parent_class>::GetTearDownCaseOrSuite(__FILE__, __LINE__), \
new ::testing::internal::TestFactoryImpl); \
void GTEST_TEST_CLASS_NAME_(test_suite_name, test_name)::TestBody()
GTEST_TEST_ 宏定义一个类，它为定义的类实现如下特性：
- 类名：类名由测试套件名、测试用例名和字符串
Test3 部分组成，不同部分用下划线分割。如TEST_F(FooTest, InitializesCorrectly)和TEST(FooTest, InitializesCorrectly)定义的类名为FooTest_InitializesCorrectly_Test。 - 父类：
GTEST_TEST_宏定义的类继承自传给它的parent_class参数类。对于TEST_F宏而言，就是测试套件名，对于TEST则是::testing::Test类。 GTEST_TEST_宏为它定义的类定义了一个空的默认构造函数。GTEST_TEST_宏为它定义的类定义并初始化类型为::testing::TestInfo* const的静态成员变量test_info_，这个指针变量指向由::testing::internal::MakeAndRegisterTestInfo()函数创建的::testing::TestInfo类型对象。::testing::internal::MakeAndRegisterTestInfo()函数还会将测试用例的信息注册给 Google Test。GTEST_TEST_宏为它定义的类定义TestBody()虚函数覆盖父类的对应函数，函数的函数体正是我们编写的测试用例代码，这也就是为什么我们在测试用例代码体中打断点时，看到调用栈，代码是位于名为TestBody()的函数中的原因。- 通过宏
GTEST_DISALLOW_COPY_AND_ASSIGN_实现类对象的禁用拷贝构造和赋值。
::testing::internal::MakeAndRegisterTestInfo() 函数定义（googletest/googletest/src/gtest.cc）如下：
// Creates a new TestInfo object and registers it with Google Test;
// returns the created object.
//
// Arguments:
//
// test_suite_name: name of the test suite
// name: name of the test
// type_param: the name of the test's type parameter, or NULL if
// this is not a typed or a type-parameterized test.
// value_param: text representation of the test's value parameter,
// or NULL if this is not a value-parameterized test.
// code_location: code location where the test is defined
// fixture_class_id: ID of the test fixture class
// set_up_tc: pointer to the function that sets up the test suite
// tear_down_tc: pointer to the function that tears down the test suite
// factory: pointer to the factory that creates a test object.
// The newly created TestInfo instance will assume
// ownership of the factory object.
TestInfo* MakeAndRegisterTestInfo(
const char* test_suite_name, const char* name, const char* type_param,
const char* value_param, CodeLocation code_location,
TypeId fixture_class_id, SetUpTestSuiteFunc set_up_tc,
TearDownTestSuiteFunc tear_down_tc, TestFactoryBase* factory) {
TestInfo* const test_info =
new TestInfo(test_suite_name, name, type_param, value_param,
code_location, fixture_class_id, factory);
GetUnitTestImpl()->AddTestInfo(set_up_tc, tear_down_tc, test_info);
return test_info;
}
测试用例的注册
在通过 TEST 和 TEST_F 宏定义测试用例时，这些宏实际上将会为测试用例定义一个类，这个类包含一个静态成员变量，在这个静态成员变量初始化时，在 ::testing::internal::MakeAndRegisterTestInfo() 函数中向 Google Test 注册测试用例，具体而言，通过 ::testing::internal::UnitTestImpl::AddTestInfo() 函数注册测试用例，该函数在 googletest/googletest/src/gtest-internal-inl.h 中定义，定义如下：
// Adds a TestInfo to the unit test.
//
// Arguments:
//
// set_up_tc: pointer to the function that sets up the test suite
// tear_down_tc: pointer to the function that tears down the test suite
// test_info: the TestInfo object
void AddTestInfo(internal::SetUpTestSuiteFunc set_up_tc,
internal::TearDownTestSuiteFunc tear_down_tc,
TestInfo* test_info) {
// In order to support thread-safe death tests, we need to
// remember the original working directory when the test program
// was first invoked. We cannot do this in RUN_ALL_TESTS(), as
// the user may have changed the current directory before calling
// RUN_ALL_TESTS(). Therefore we capture the current directory in
// AddTestInfo(), which is called to register a TEST or TEST_F
// before main() is reached.
if (original_working_dir_.IsEmpty()) {
original_working_dir_.Set(FilePath::GetCurrentDir());
GTEST_CHECK_(!original_working_dir_.IsEmpty())
<< "Failed to get the current working directory.";
}
GetTestSuite(test_info->test_suite_name(), test_info->type_param(),
set_up_tc, tear_down_tc)
->AddTestInfo(test_info);
}
::testing::internal::UnitTestImpl::AddTestInfo() 函数根据测试套件名字等参数获得测试套件；然后将测试用例添加进测试套件中。
googletest/googletest/src/gtest.cc 中用于获得测试套件的 ::testing::internal::UnitTestImpl::GetTestSuite() 函数定义如下：
// Finds and returns a TestSuite with the given name. If one doesn't
// exist, creates one and returns it. It's the CALLER'S
// RESPONSIBILITY to ensure that this function is only called WHEN THE
// TESTS ARE NOT SHUFFLED.
//
// Arguments:
//
// test_suite_name: name of the test suite
// type_param: the name of the test suite's type parameter, or NULL if
// this is not a typed or a type-parameterized test suite.
// set_up_tc: pointer to the function that sets up the test suite
// tear_down_tc: pointer to the function that tears down the test suite
TestSuite* UnitTestImpl::GetTestSuite(
const char* test_suite_name, const char* type_param,
internal::SetUpTestSuiteFunc set_up_tc,
internal::TearDownTestSuiteFunc tear_down_tc) {
// Can we find a TestSuite with the given name?
const auto test_suite =
std::find_if(test_suites_.rbegin(), test_suites_.rend(),
TestSuiteNameIs(test_suite_name));
if (test_suite != test_suites_.rend()) return *test_suite;
// No. Let's create one.
auto* const new_test_suite =
new TestSuite(test_suite_name, type_param, set_up_tc, tear_down_tc);
// Is this a death test suite?
if (internal::UnitTestOptions::MatchesFilter(test_suite_name,
kDeathTestSuiteFilter)) {
// Yes. Inserts the test suite after the last death test suite
// defined so far. This only works when the test suites haven't
// been shuffled. Otherwise we may end up running a death test
// after a non-death test.
++last_death_test_suite_;
test_suites_.insert(test_suites_.begin() + last_death_test_suite_,
new_test_suite);
} else {
// No. Appends to the end of the list.
test_suites_.push_back(new_test_suite);
}
test_suite_indices_.push_back(static_cast(test_suite_indices_.size()));
return new_test_suite;
}
::testing::internal::UnitTestImpl::GetTestSuite() 函数：
- 根据传入的测试套件名在测试套件 vector 中查找测试套件，如果找到就返回。
- 在测试套件 vector 中没有找到对应的测试套件，创建一个测试套件
TestSuite对象。 - 测试套件名字与 death test 测试套件名规则匹配时，创建的测试套件被放在测试套件 vector 的前面，并在执行时先执行。
- 测试套件名字与 death test 测试套件名规则不匹配时，创建的测试套件被放在测试套件 vector 的后面，并在执行时后执行。
向 TestSuite 添加测试用例的 TestSuite::AddTestInfo() 函数定义（googletest/googletest/src/gtest.cc）如下：
// Adds a test to this test suite. Will delete the test upon
// destruction of the TestSuite object.
void TestSuite::AddTestInfo(TestInfo* test_info) {
test_info_list_.push_back(test_info);
test_indices_.push_back(static_cast(test_indices_.size()));
}
测试用例的执行
在 main() 函数中，通过调用 testing::InitGoogleTest(&argc, argv) 和 RUN_ALL_TESTS() 执行所有的测试用例。testing::InitGoogleTest(&argc, argv) 主要用于解析命令行参数，如 filter 等，这里不再详细分析。googletest/googletest/include/gtest/gtest.h 中的 RUN_ALL_TESTS() 函数定义如下：
// Use this function in main() to run all tests. It returns 0 if all
// tests are successful, or 1 otherwise.
//
// RUN_ALL_TESTS() should be invoked after the command line has been
// parsed by InitGoogleTest().
//
// This function was formerly a macro; thus, it is in the global
// namespace and has an all-caps name.
int RUN_ALL_TESTS() GTEST_MUST_USE_RESULT_;
inline int RUN_ALL_TESTS() {
return ::testing::UnitTest::GetInstance()->Run();
}
RUN_ALL_TESTS() 函数调用 googletest/googletest/src/gtest.cc 中定义的 UnitTest::Run() 函数执行所有的测试用例：
// Runs all tests in this UnitTest object and prints the result.
// Returns 0 if successful, or 1 otherwise.
//
// We don't protect this under mutex_, as we only support calling it
// from the main thread.
int UnitTest::Run() {
const bool in_death_test_child_process =
internal::GTEST_FLAG(internal_run_death_test).length() > 0;
// Google Test implements this protocol for catching that a test
// program exits before returning control to Google Test:
//
// 1. Upon start, Google Test creates a file whose absolute path
// is specified by the environment variable
// TEST_PREMATURE_EXIT_FILE.
// 2. When Google Test has finished its work, it deletes the file.
//
// This allows a test runner to set TEST_PREMATURE_EXIT_FILE before
// running a Google-Test-based test program and check the existence
// of the file at the end of the test execution to see if it has
// exited prematurely.
// If we are in the child process of a death test, don't
// create/delete the premature exit file, as doing so is unnecessary
// and will confuse the parent process. Otherwise, create/delete
// the file upon entering/leaving this function. If the program
// somehow exits before this function has a chance to return, the
// premature-exit file will be left undeleted, causing a test runner
// that understands the premature-exit-file protocol to report the
// test as having failed.
const internal::ScopedPrematureExitFile premature_exit_file(
in_death_test_child_process
? nullptr
: internal::posix::GetEnv("TEST_PREMATURE_EXIT_FILE"));
// Captures the value of GTEST_FLAG(catch_exceptions). This value will be
// used for the duration of the program.
impl()->set_catch_exceptions(GTEST_FLAG(catch_exceptions));
#if GTEST_OS_WINDOWS
// Either the user wants Google Test to catch exceptions thrown by the
// tests or this is executing in the context of death test child
// process. In either case the user does not want to see pop-up dialogs
// about crashes - they are expected.
if (impl()->catch_exceptions() || in_death_test_child_process) {
# if !GTEST_OS_WINDOWS_MOBILE && !GTEST_OS_WINDOWS_PHONE && !GTEST_OS_WINDOWS_RT
// SetErrorMode doesn't exist on CE.
SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOALIGNMENTFAULTEXCEPT |
SEM_NOGPFAULTERRORBOX | SEM_NOOPENFILEERRORBOX);
# endif // !GTEST_OS_WINDOWS_MOBILE
# if (defined(_MSC_VER) || GTEST_OS_WINDOWS_MINGW) && !GTEST_OS_WINDOWS_MOBILE
// Death test children can be terminated with _abort(). On Windows,
// _abort() can show a dialog with a warning message. This forces the
// abort message to go to stderr instead.
_set_error_mode(_OUT_TO_STDERR);
# endif
# if defined(_MSC_VER) && !GTEST_OS_WINDOWS_MOBILE
// In the debug version, Visual Studio pops up a separate dialog
// offering a choice to debug the aborted program. We need to suppress
// this dialog or it will pop up for every EXPECT/ASSERT_DEATH statement
// executed. Google Test will notify the user of any unexpected
// failure via stderr.
if (!GTEST_FLAG(break_on_failure))
_set_abort_behavior(
0x0, // Clear the following flags:
_WRITE_ABORT_MSG | _CALL_REPORTFAULT); // pop-up window, core dump.
# endif
}
#endif // GTEST_OS_WINDOWS
return internal::HandleExceptionsInMethodIfSupported(
impl(),
&internal::UnitTestImpl::RunAllTests,
"auxiliary test code (environments or event listeners)") ? 0 : 1;
}
internal::HandleExceptionsInMethodIfSupported() 是 Google test 定义的一个用于执行类的成员函数的函数，这里不再详细分析这个函数的实现。UnitTest::Run() 函数实际上通过 googletest/googletest/src/gtest.cc 中定义的 internal::UnitTestImpl::RunAllTests() 函数执行所有的测试用例：
// Runs all tests in this UnitTest object, prints the result, and
// returns true if all tests are successful. If any exception is
// thrown during a test, the test is considered to be failed, but the
// rest of the tests will still be run.
//
// When parameterized tests are enabled, it expands and registers
// parameterized tests first in RegisterParameterizedTests().
// All other functions called from RunAllTests() may safely assume that
// parameterized tests are ready to be counted and run.
bool UnitTestImpl::RunAllTests() {
// True iff Google Test is initialized before RUN_ALL_TESTS() is called.
const bool gtest_is_initialized_before_run_all_tests = GTestIsInitialized();
// Do not run any test if the --help flag was specified.
if (g_help_flag)
return true;
// Repeats the call to the post-flag parsing initialization in case the
// user didn't call InitGoogleTest.
PostFlagParsingInit();
// Even if sharding is not on, test runners may want to use the
// GTEST_SHARD_STATUS_FILE to query whether the test supports the sharding
// protocol.
internal::WriteToShardStatusFileIfNeeded();
// True iff we are in a subprocess for running a thread-safe-style
// death test.
bool in_subprocess_for_death_test = false;
#if GTEST_HAS_DEATH_TEST
in_subprocess_for_death_test =
(internal_run_death_test_flag_.get() != nullptr);
# if defined(GTEST_EXTRA_DEATH_TEST_CHILD_SETUP_)
if (in_subprocess_for_death_test) {
GTEST_EXTRA_DEATH_TEST_CHILD_SETUP_();
}
# endif // defined(GTEST_EXTRA_DEATH_TEST_CHILD_SETUP_)
#endif // GTEST_HAS_DEATH_TEST
const bool should_shard = ShouldShard(kTestTotalShards, kTestShardIndex,
in_subprocess_for_death_test);
// Compares the full test names with the filter to decide which
// tests to run.
const bool has_tests_to_run = FilterTests(should_shard
? HONOR_SHARDING_PROTOCOL
: IGNORE_SHARDING_PROTOCOL) > 0;
// Lists the tests and exits if the --gtest_list_tests flag was specified.
if (GTEST_FLAG(list_tests)) {
// This must be called *after* FilterTests() has been called.
ListTestsMatchingFilter();
return true;
}
random_seed_ = GTEST_FLAG(shuffle) ?
GetRandomSeedFromFlag(GTEST_FLAG(random_seed)) : 0;
// True iff at least one test has failed.
bool failed = false;
TestEventListener* repeater = listeners()->repeater();
start_timestamp_ = GetTimeInMillis();
repeater->OnTestProgramStart(*parent_);
// How many times to repeat the tests? We don't want to repeat them
// when we are inside the subprocess of a death test.
const int repeat = in_subprocess_for_death_test ? 1 : GTEST_FLAG(repeat);
// Repeats forever if the repeat count is negative.
const bool gtest_repeat_forever = repeat < 0;
for (int i = 0; gtest_repeat_forever || i != repeat; i++) {
// We want to preserve failures generated by ad-hoc test
// assertions executed before RUN_ALL_TESTS().
ClearNonAdHocTestResult();
const TimeInMillis start = GetTimeInMillis();
// Shuffles test suites and tests if requested.
if (has_tests_to_run && GTEST_FLAG(shuffle)) {
random()->Reseed(static_cast(random_seed_));
// This should be done before calling OnTestIterationStart(),
// such that a test event listener can see the actual test order
// in the event.
ShuffleTests();
}
// Tells the unit test event listeners that the tests are about to start.
repeater->OnTestIterationStart(*parent_, i);
// Runs each test suite if there is at least one test to run.
if (has_tests_to_run) {
// Sets up all environments beforehand.
repeater->OnEnvironmentsSetUpStart(*parent_);
ForEach(environments_, SetUpEnvironment);
repeater->OnEnvironmentsSetUpEnd(*parent_);
// Runs the tests only if there was no fatal failure or skip triggered
// during global set-up.
if (Test::IsSkipped()) {
// Emit diagnostics when global set-up calls skip, as it will not be
// emitted by default.
TestResult& test_result =
*internal::GetUnitTestImpl()->current_test_result();
for (int j = 0; j < test_result.total_part_count(); ++j) {
const TestPartResult& test_part_result =
test_result.GetTestPartResult(j);
if (test_part_result.type() == TestPartResult::kSkip) {
const std::string& result = test_part_result.message();
printf("%s\n", result.c_str());
}
}
fflush(stdout);
} else if (!Test::HasFatalFailure()) {
for (int test_index = 0; test_index < total_test_suite_count();
test_index++) {
GetMutableSuiteCase(test_index)->Run();
}
}
// Tears down all environments in reverse order afterwards.
repeater->OnEnvironmentsTearDownStart(*parent_);
std::for_each(environments_.rbegin(), environments_.rend(),
TearDownEnvironment);
repeater->OnEnvironmentsTearDownEnd(*parent_);
}
elapsed_time_ = GetTimeInMillis() - start;
// Tells the unit test event listener that the tests have just finished.
repeater->OnTestIterationEnd(*parent_, i);
// Gets the result and clears it.
if (!Passed()) {
failed = true;
}
// Restores the original test order after the iteration. This
// allows the user to quickly repro a failure that happens in the
// N-th iteration without repeating the first (N - 1) iterations.
// This is not enclosed in "if (GTEST_FLAG(shuffle)) { ... }", in
// case the user somehow changes the value of the flag somewhere
// (it's always safe to unshuffle the tests).
UnshuffleTests();
if (GTEST_FLAG(shuffle)) {
// Picks a new random seed for each iteration.
random_seed_ = GetNextRandomSeed(random_seed_);
}
}
repeater->OnTestProgramEnd(*parent_);
if (!gtest_is_initialized_before_run_all_tests) {
ColoredPrintf(
COLOR_RED,
"\nIMPORTANT NOTICE - DO NOT IGNORE:\n"
"This test program did NOT call " GTEST_INIT_GOOGLE_TEST_NAME_
"() before calling RUN_ALL_TESTS(). This is INVALID. Soon " GTEST_NAME_
" will start to enforce the valid usage. "
"Please fix it ASAP, or IT WILL START TO FAIL.\n"); // NOLINT
#if GTEST_FOR_GOOGLE_
ColoredPrintf(COLOR_RED,
"For more details, see http://wiki/Main/ValidGUnitMain.\n");
#endif // GTEST_FOR_GOOGLE_
}
return !failed;
}
internal::UnitTestImpl::RunAllTests() 函数通过 internal::UnitTestImpl::GetMutableSuiteCase() 函数拿到测试套件 TestSuite 并执行其 Run() 函数：
void TestSuite::Run() {
if (!should_run_) return;
internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
impl->set_current_test_suite(this);
TestEventListener* repeater = UnitTest::GetInstance()->listeners().repeater();
// Call both legacy and the new API
repeater->OnTestSuiteStart(*this);
// Legacy API is deprecated but still available
#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI
repeater->OnTestCaseStart(*this);
#endif // GTEST_REMOVE_LEGACY_TEST_CASEAPI
impl->os_stack_trace_getter()->UponLeavingGTest();
internal::HandleExceptionsInMethodIfSupported(
this, &TestSuite::RunSetUpTestSuite, "SetUpTestSuite()");
start_timestamp_ = internal::GetTimeInMillis();
for (int i = 0; i < total_test_count(); i++) {
GetMutableTestInfo(i)->Run();
}
elapsed_time_ = internal::GetTimeInMillis() - start_timestamp_;
impl->os_stack_trace_getter()->UponLeavingGTest();
internal::HandleExceptionsInMethodIfSupported(
this, &TestSuite::RunTearDownTestSuite, "TearDownTestSuite()");
// Call both legacy and the new API
repeater->OnTestSuiteEnd(*this);
// Legacy API is deprecated but still available
#ifndef GTEST_REMOVE_LEGACY_TEST_CASEAPI
repeater->OnTestCaseEnd(*this);
#endif // GTEST_REMOVE_LEGACY_TEST_CASEAPI
impl->set_current_test_suite(nullptr);
}
TestSuite::Run() 函数通过 GetMutableTestInfo() 函数获得 TestInfo 并执行其 Run() 函数，TestInfo::Run() 函数定义如下：
// Creates the test object, runs it, records its result, and then
// deletes it.
void TestInfo::Run() {
if (!should_run_) return;
// Tells UnitTest where to store test result.
internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
impl->set_current_test_info(this);
TestEventListener* repeater = UnitTest::GetInstance()->listeners().repeater();
// Notifies the unit test event listeners that a test is about to start.
repeater->OnTestStart(*this);
const TimeInMillis start = internal::GetTimeInMillis();
impl->os_stack_trace_getter()->UponLeavingGTest();
// Creates the test object.
Test* const test = internal::HandleExceptionsInMethodIfSupported(
factory_, &internal::TestFactoryBase::CreateTest,
"the test fixture's constructor");
// Runs the test if the constructor didn't generate a fatal failure or invoke
// GTEST_SKIP().
// Note that the object will not be null
if (!Test::HasFatalFailure() && !Test::IsSkipped()) {
// This doesn't throw as all user code that can throw are wrapped into
// exception handling code.
test->Run();
}
if (test != nullptr) {
// Deletes the test object.
impl->os_stack_trace_getter()->UponLeavingGTest();
internal::HandleExceptionsInMethodIfSupported(
test, &Test::DeleteSelf_, "the test fixture's destructor");
}
result_.set_start_timestamp(start);
result_.set_elapsed_time(internal::GetTimeInMillis() - start);
// Notifies the unit test event listener that a test has just finished.
repeater->OnTestEnd(*this);
// Tells UnitTest to stop associating assertion results to this
// test.
impl->set_current_test_info(nullptr);
}
TestInfo::Run() 函数创建测试用例类对象，并执行其 Run() 函数。Test::Run() 执行测试用例定义的 SetUp()，测试用例主体 TestBody() 函数，和 TearDown() 函数：
// Runs the test and updates the test result.
void Test::Run() {
if (!HasSameFixtureClass()) return;
internal::UnitTestImpl* const impl = internal::GetUnitTestImpl();
impl->os_stack_trace_getter()->UponLeavingGTest();
internal::HandleExceptionsInMethodIfSupported(this, &Test::SetUp, "SetUp()");
// We will run the test only if SetUp() was successful and didn't call
// GTEST_SKIP().
if (!HasFatalFailure() && !IsSkipped()) {
impl->os_stack_trace_getter()->UponLeavingGTest();
internal::HandleExceptionsInMethodIfSupported(
this, &Test::TestBody, "the test body");
}
// However, we want to clean up as much as possible. Hence we will
// always call TearDown(), even if SetUp() or the test body has
// failed.
impl->os_stack_trace_getter()->UponLeavingGTest();
internal::HandleExceptionsInMethodIfSupported(
this, &Test::TearDown, "TearDown()");
}
测试用例的调用执行过程大概是这样的：
RUN_ALL_TESTS() -> UnitTest::Run() -> UnitTestImpl::RunAllTests() -> TestSuite::Run() -> TestInfo::Run() -> Test::Run() -> Test::TestBody()。
Done。