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有一个玩转GoogleTest的文章讲的不错,值得花点时间看下

一些使用方法

最近使用googletest,新加了单元测试,就需要判定开关单元测试对原来测试的影响,做个记录

./db_iterator_test --gtest_filter=-DBIteratorTestInstance/DBIteratorTest.IterSeekBeforePrevWithTimestamp/*

过滤用例,也可以代码中加DISABLED_

TEST(FooTest, DISABLED_DoesAbc) { ... }

过滤多个用例,匹配模式之间用分好隔开

./table_test  --gtest_filter=*FilterBlockInBlockCache:*BasicBlockBasedTableProperties

测试的准备工作 针对testsuits

全局预设定, 实现下面的接口,一个testsuit执行一次,可以实现

static void SetUpTestSuite() {}
static void TearDownTestSuite() {}

注意是static

针对每一个小测试,实现下面的接口,每个test_f都会执行一次

virtual void SetUp() {}
virtual void TearDown() {}     

gmock

常用

using ::testing::Return;
using ::testing::_;

InSequence实现DAG菱形结构,拆分成一条一条的拼起来就行

InSequence s1, s2;
EXPECT_CALL(_,  A()).InSequence(s1, s2);
EXPECT_CALL(_, B1()).InSequence(s1    );
EXPECT_CALL(_, B2()).InSequence(    s2);
EXPECT_CALL(_,  C()).InSequence(s1, s2);

gdb调试googletest

 gdb --args  db_iterator_test --gtest_filter=-DBIteratorTestInstance/DBIteratorTest.IterSeekBeforePrevWithTimestamp/1

打断点有点麻烦,得nm抓符号名,一般都是类名/单元测试类名字_TestBody

gtest命令行

命令行参数 说明
–gtest_list_tests 使用这个参数时,将不会执行里面的测试案例,而是输出一个案例的列表。
–gtest_filter 对执行的测试案例进行过滤,支持通配符? 单个字符* 任意字符- 排除,如,-a 表示除了a : 取或,如,a:b 表示a或b 比如下面的例子:./foo_test 没有指定过滤条件,运行所有案例 ./foo_test –gtest_filter=* 使用通配符,表示运行所有案例 ./foo_test –gtest_filter=FooTest. 运行所有“测试案例名称(testcase_name)”为FooTest的案例 ./foo_test –gtest_filter=Null:Constructor 运行所有“测试案例名称(testcase_name)”或“测试名称(test_name)”包含Null或Constructor的案例。 ./foo_test –gtest_filter=-DeathTest. 运行所有非死亡测试案例。 ./foo_test –gtest_filter=FooTest.*-FooTest.Bar 运行所有“测试案例名称(testcase_name)”为FooTest的案例,但是除了FooTest.Bar这个案例
–gtest_also_run_disabled_tests 执行案例时,同时也执行被置为无效的测试案例。关于设置测试案例无效的方法为:在测试案例名称或测试名称中添加DISABLED前缀,比如:复制代码// Tests that Foo does Abc. TEST(FooTest, DISABLED_DoesAbc) { img } class DISABLED_BarTest : public testing::Test { img }; // Tests that Bar does Xyz. TEST_F(DISABLED_BarTest, DoesXyz) { img }复制代码
–gtest_repeat=[COUNT] 设置案例重复运行次数,非常棒的功能!比如:–gtest_repeat=1000 重复执行1000次,即使中途出现错误。 –gtest_repeat=-1 无限次数执行。。。。 –gtest_repeat=1000 –gtest_break_on_failure 重复执行1000次,并且在第一个错误发生时立即停止。这个功能对调试非常有用。 –gtest_repeat=1000 –gtest_filter=FooBar 重复执行1000次测试案例名称为FooBar的案例。

测试案例输出

命令行参数 说明
–gtest_color=(yes|no|auto) 输出命令行时是否使用一些五颜六色的颜色。默认是auto。
–gtest_print_time 输出命令行时是否打印每个测试案例的执行时间。默认是不打印的。
–gtest_output=xml[:DIRECTORY_PATH|:FILE_PATH] 将测试结果输出到一个xml中。1.–gtest_output=xml: 不指定输出路径时,默认为案例当前路径。 2.–gtest_output=xml:d:\ 指定输出到某个目录 3.–gtest_output=xml:d:\foo.xml 指定输出到d:\foo.xml 如果不是指定了特定的文件路径,gtest每次输出的报告不会覆盖,而会以数字后缀的方式创建。xml的输出内容后面介绍吧。

对案例的异常处理

命令行参数 说明
–gtest_break_on_failure 调试模式下,当案例失败时停止,方便调试
–gtest_throw_on_failure 当案例失败时以C++异常的方式抛出
–gtest_catch_exceptions 是否捕捉异常。gtest默认是不捕捉异常的,因此假如你的测试案例抛了一个异常,很可能会弹出一个对话框,这非常的不友好,同时也阻碍了测试案例的运行。如果想不弹这个框,可以通过设置这个参数来实现。如将–gtest_catch_exceptions设置为一个非零的数。注意:这个参数只在Windows下有效。

说到问题,有这么个测试错误,应该是key1后面多了一串0

db/db_log_iter_test.cc:280: Failure
Value of: handler.seen
  Actual: "Put(1, key1\0\0\0\0\0\0\0\0, 1024)Put(0, key2\0\0\0\0\0\0\0\0, 1024)LogData(blob1\0\0\0\0\0\0\0\0)Put(1, key3\0\0\0\0\0\0\0\0, 1024)LogData(blob2\0\0\0\0\0\0\0\0)Delete(0, key2\0\0\0\0\0\0\0\0)"
Expected: "Put(1, key1, 1024)" "Put(0, key2, 1024)" "LogData(blob1)" "Put(1, key3, 1024)" "LogData(blob2)" "Delete(0, key2)"
Which is: "Put(1, key1, 1024)Put(0, key2, 1024)LogData(blob1)Put(1, key3, 1024)LogData(blob2)Delete(0, key2)"
[  FAILED  ] DBTestXactLogIterator.TransactionLogIteratorBlobs (102 ms)

这两个是同一个字符串

#include <iostream>
#include <string>
#include <iomanip>
std::string s1="Put(1, key1, 1024)" "Put(0, key2, 1024)" "LogData(blob1)" "Put(1, key3, 1024)" "LogData(blob2)" "Delete(0, key2)";
std::string s2="Put(1, key1, 1024)Put(0, key2, 1024)LogData(blob1)Put(1, key3, 1024)LogData(blob2)Delete(0, key2)";

int main()
{
    bool b = s1==s2;
    std::cout<<std::boolalpha << b << std::endl;// true
}

EXCEPT_EQ

#define GTEST_ASSERT_EQ(expected, actual) \
  ASSERT_PRED_FORMAT2(::testing::internal:: \
                      EqHelper<GTEST_IS_NULL_LITERAL_(expected)>::Compare, \
                      expected, actual)
//这个宏展开就是f(#a,#b,a,b)
//EqHelper 偏特化 如果是null就是eqhelper<true>

template <bool lhs_is_null_literal>
class EqHelper {
 public:
  // This templatized version is for the general case.
  template <typename T1, typename T2>
  static AssertionResult Compare(const char* expected_expression,
                                 const char* actual_expression,
                                 const T1& expected,
                                 const T2& actual) {
    return CmpHelperEQ(expected_expression, actual_expression, expected,
                       actual);
  }

  // With this overloaded version, we allow anonymous enums to be used
  // in {ASSERT|EXPECT}_EQ when compiled with gcc 4, as anonymous
  // enums can be implicitly cast to BiggestInt.
  //
  // Even though its body looks the same as the above version, we
  // cannot merge the two, as it will make anonymous enums unhappy.
  static AssertionResult Compare(const char* expected_expression,
                                 const char* actual_expression,
                                 BiggestInt expected,
                                 BiggestInt actual) {
    return CmpHelperEQ(expected_expression, actual_expression, expected,
                       actual);
  }
};

// This specialization is used when the first argument to ASSERT_EQ()
// is a null pointer literal, like NULL, false, or 0.
template <>
class EqHelper<true> {
 public:
  // We define two overloaded versions of Compare().  The first
  // version will be picked when the second argument to ASSERT_EQ() is
  // NOT a pointer, e.g. ASSERT_EQ(0, AnIntFunction()) or
  // EXPECT_EQ(false, a_bool).
  template <typename T1, typename T2>
  static AssertionResult Compare(
      const char* expected_expression,
      const char* actual_expression,
      const T1& expected,
      const T2& actual,
      // The following line prevents this overload from being considered if T2
      // is not a pointer type.  We need this because ASSERT_EQ(NULL, my_ptr)
      // expands to Compare("", "", NULL, my_ptr), which requires a conversion
      // to match the Secret* in the other overload, which would otherwise make
      // this template match better.
      typename EnableIf<!is_pointer<T2>::value>::type* = 0) {
    return CmpHelperEQ(expected_expression, actual_expression, expected,
                       actual);
  }

  // This version will be picked when the second argument to ASSERT_EQ() is a
  // pointer, e.g. ASSERT_EQ(NULL, a_pointer).
  template <typename T>
  static AssertionResult Compare(
      const char* expected_expression,
      const char* actual_expression,
      // We used to have a second template parameter instead of Secret*.  That
      // template parameter would deduce to 'long', making this a better match
      // than the first overload even without the first overload's EnableIf.
      // Unfortunately, gcc with -Wconversion-null warns when "passing NULL to
      // non-pointer argument" (even a deduced integral argument), so the old
      // implementation caused warnings in user code.
      Secret* /* expected (NULL) */,
      T* actual) {
    // We already know that 'expected' is a null pointer.
    return CmpHelperEQ(expected_expression, actual_expression,
                       static_cast<T*>(NULL), actual);
  }
};
//核心就是这个了
// The helper function for {ASSERT|EXPECT}_EQ.
template <typename T1, typename T2>
AssertionResult CmpHelperEQ(const char* expected_expression,
                            const char* actual_expression,
                            const T1& expected,
                            const T2& actual) {
GTEST_DISABLE_MSC_WARNINGS_PUSH_(4389 /* signed/unsigned mismatch */)
  if (expected == actual) {
    return AssertionSuccess();
  }
GTEST_DISABLE_MSC_WARNINGS_POP_()

  return CmpHelperEQFailure(expected_expression, actual_expression, expected,
                            actual);
}

const std::string& 在gtest使用中出现的一个奇怪的堆栈

#0  0x00000000004f6e33 in __gnu_cxx::__atomic_add (
    __mem=0x7fffbf8c46ac <testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*)+93>, __val=1) at /usr/lib/gcc/x86_64-redhat-linux/7/../../../../include/c++/7/ext/atomicity.h:53
#1  0x00000000004f6ef3 in __gnu_cxx::__atomic_add_dispatch (
    __mem=0x7fffbf8c46ac <testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*)+93>, __val=1) at /usr/lib/gcc/x86_64-redhat-linux/7/../../../../include/c++/7/ext/atomicity.h:96
#2  0x00000000005034fa in std::string::_Rep::_M_refcopy (
    this=0x7fffbf8c469c <testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*)+77>) at /usr/lib/gcc/x86_64-redhat-linux/7/../../../../include/c++/7/bits/basic_string.h:3265
#3  0x0000000000500802 in std::string::_Rep::_M_grab (
    this=0x7fffbf8c469c <testing::internal::HandleSehExceptionsInMethodIfSupported<testing::Test, void>(testing::Test*, void (testing::Test::*)(), char const*)+77>, __alloc1=..., __alloc2=...) at /usr/lib/gcc/x86_64-redhat-linux/7/../../../../include/c++/7/bits/basic_string.h:3223
#4  0x00000000004fe2b8 in std::string::assign (this=0x7fffffffdd98, __str=...)
    at /usr/lib/gcc/x86_64-redhat-linux/7/../../../../include/c++/7/bits/basic_string.tcc:699
#5  0x00000000004fdddf in std::string::operator= (this=0x7fffffffdd98, __str=...)
    at /usr/lib/gcc/x86_64-redhat-linux/7/../../../../include/c++/7/bits/basic_string.h:3629

测试常用小代码段

  • 随机生成字符串
#include <algorithm>
#include <string>
std::string random_string(size_t length = 10) {
  auto randchar = []() -> char
  {
      const char charset[] =
      "0123456789"
      "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
      "abcdefghijklmnopqrstuvwxyz";
      const size_t max_index = (sizeof(charset) - 1);
      return charset[ rand() % max_index ];
  };
  std::string str(length,0);
  std::generate_n( str.begin(), length, randchar );
  return str;
}

INSTANTIATE_TEST_CASE_P 生成参数组合用例

另外,单元测试太多,写了个小脚本,抓出失败的

#!/bin/bash
for file in *test
do
  ./$file > /dev/null 2>&1
  if [[ $? != 0 ]]
  then
    echo $file
  fi
done

事件监听器?testing::TestEventListener 没用过

执行原理,一图流

参考