tdd - 如何在Google测试中为多个测试初始化​​常量字符串？

Question

我正在使用Google测试，并且我有一个包含多个测试的cpp文件。我想在开始第一次测试时用当前的日期和时间初始化一个字符串。我也想在所有其他测试中使用此字符串。我怎样才能做到这一点。

我已经尝试了以下操作(m_string是CnFirstTest的 protected 成员)，但是它没有用(因为在每次测试之前都会调用构造函数和SetUp):

CnFirstTest::CnFirstTest(void) {
    m_string = currentDateTime();
}

void CnFirstTest::SetUp() {
}



TEST_F(CnFirstTest, Test1) {
    // use m_string
}

TEST_F(CnFirstTest, Test2) {
    // use m_string, too
}

Answer 1

您可以使用gtest testing::Environment 实现此目的:

#include <chrono>
#include <iostream>

#include "gtest/gtest.h"

std::string currentDateTime() {
  return std::to_string(std::chrono::steady_clock::now().time_since_epoch().count());
}

class TestEnvironment : public ::testing::Environment {
 public:
  // Assume there's only going to be a single instance of this class, so we can just
  // hold the timestamp as a const static local variable and expose it through a
  // static member function
  static std::string getStartTime() {
    static const std::string timestamp = currentDateTime();
    return timestamp;
  }

  // Initialise the timestamp.
  virtual void SetUp() { getStartTime(); }
};

class CnFirstTest : public ::testing::Test {
 protected:
  virtual void SetUp() { m_string = currentDateTime(); }
  std::string m_string;
};

TEST_F(CnFirstTest, Test1) {
  std::cout << TestEnvironment::getStartTime() << std::endl;
  std::cout << m_string << std::endl;
}

TEST_F(CnFirstTest, Test2) {
  std::cout << TestEnvironment::getStartTime() << std::endl;
  std::cout << m_string << std::endl;
}

int main(int argc, char* argv[]) {
  ::testing::InitGoogleTest(&argc, argv);
  // gtest takes ownership of the TestEnvironment ptr - we don't delete it.
  ::testing::AddGlobalTestEnvironment(new TestEnvironment);
  return RUN_ALL_TESTS();
}