gtest 简单指北

源码地址: https://github.com/lambertxiao/gtest-lesson

准备工作

下载googletest库，并编译安装

googletest源码地址：https://github.com/google/googletest googletest文档地址：https://google.github.io/googletest/

怎么运行当前示例

mkdir build
cd build
cmake ../ && make
./test_main

示例讲解

test1.cpp

演示了如何做最基本的单元测试

#include <gtest/gtest.h>

int add(int x, int y) {
  return x + y;
}

TEST(AdditionTest, testAdd) {
  EXPECT_EQ(add(1, 2), 3);
}

test2.cpp

演示了如何写一个测试用例集

#include <gtest/gtest.h>

class Math {
 public:
  int add(int x, int y) {
    return x + y;
  }
  int sub(int x, int y) {
    return x - y;
  }
};

class MathTestSuite : public testing::Test {
 protected:
  Math math;
};

TEST_F(MathTestSuite, testAdd) {
  EXPECT_EQ(math.add(1, 2), 3);
}

TEST_F(MathTestSuite, testSub) {
  EXPECT_EQ(math.sub(3, 1), 2);
}

test3.cpp

演示了如何做mock测试，定义了一个简单的常见,FileWriter需要依赖DiskUtil做文件写入，而通过mock掉DiskUtil的写入返回值，从而决定FileWriter应该执行什么逻辑

#include <gtest/gtest.h>
#include <gmock/gmock.h>

using ::testing::Return;
using ::testing::StrictMock;

class IDiskUitl {
 public:
  virtual int write(int offset, char* data, int len) = 0;
};

class FileWriter {
 public:
  IDiskUitl* diskutil_;
  uint64_t offset_;

  FileWriter(IDiskUitl *diskutil, uint64_t offset) : diskutil_(diskutil), offset_(offset) {}

  int writeFile(char* data, int len) {
    int ret = diskutil_->write(offset_, data, len);
    if (ret == 0) {
      offset_ += len;
    }
    return ret;
  }
};

class MockDiskUtil : public IDiskUitl {
 public:
  MOCK_METHOD(int, write, (int, char*, int), (override));
};

class FileWriterTestSuite : public testing::Test {
 protected:
  // 每个case执行前都会调用
  void SetUp() override {}

  StrictMock<MockDiskUtil> diskutil_;
};

TEST_F(FileWriterTestSuite, testWriteSuccess) {
  uint64_t woff = 1024;
  FileWriter w(&diskutil_, woff);

  std::string data = "hello";
  EXPECT_CALL(diskutil_, write(woff, (char*)data.c_str(), data.length())).WillOnce(Return(0));

  int ret = w.writeFile((char*)data.c_str(), data.length());
  EXPECT_EQ(ret, 0);
  EXPECT_EQ(w.offset_, woff + data.length());
}

TEST_F(FileWriterTestSuite, testWriteFailed) {
  uint64_t woff = 1024;
  FileWriter w(&diskutil_, woff);

  std::string data = "hello";
  EXPECT_CALL(diskutil_, write(woff, (char*)data.c_str(), data.length())).WillOnce(Return(1));

  int ret = w.writeFile((char*)data.c_str(), data.length());
  EXPECT_EQ(ret, 1);
  EXPECT_EQ(w.offset_, woff);
}