googletest：sample5分析

目录

• 测试文件
• 小结

测试文件

sample5对sample1, 3进行了性能测试，即要求每个测试须在5秒内结束；否则，算作测试失败.

设计了一个夹具类QuickTest 断言执行用例时间是否在5秒内，从而决定测试是否通过. 其中，SetUp()会在执行用例前自动调用，TearDown()会在执行用例后自动调用.

sample4没有直接用夹具类QuickTest进行测试，而是用新子类IntegerFunctionTest进行测试.

只需要将测试组件修改为新的子类，与sample1相比，在不修改测试用例内容情况下，能额外测试函数的执行时间性能.

// sample5_unittest.cc

#include <limits.h>
#include <time.h>

#include "sample1.h"
#include "sample3-inl.h"
#include "gtest/gtest.h"
namespace {
// In this sample, we want to ensure that every test finishes within
// ~5 seconds.  If a test takes longer to run, we consider it a
// failure.
//
// We put the code for timing a test in a test fixture called
// "QuickTest".  QuickTest is intended to be the super fixture that
// other fixtures derive from, therefore there is no test case with
// the name "QuickTest".  This is OK.
//
// Later, we will derive multiple test fixtures from QuickTest.
class QuickTest : public testing::Test {
 protected:
  // Remember that SetUp() is run immediately before a test starts.
  // This is a good place to record the start time.
  void SetUp() override { start_time_ = time(nullptr); }

  // TearDown() is invoked immediately after a test finishes.  Here we
  // check if the test was too slow.
  void TearDown() override {
    // Gets the time when the test finishes
    const time_t end_time = time(nullptr);

    // Asserts that the test took no more than ~5 seconds.  Did you
    // know that you can use assertions in SetUp() and TearDown() as
    // well?
    EXPECT_TRUE(end_time - start_time_ <= 5) << "The test took too long.";
  }

  // The UTC time (in seconds) when the test starts
  time_t start_time_;
};

// We derive a fixture named IntegerFunctionTest from the QuickTest
// fixture.  All tests using this fixture will be automatically
// required to be quick.
class IntegerFunctionTest : public QuickTest {
  // We don't need any more logic than already in the QuickTest fixture.
  // Therefore the body is empty.
};

// Now we can write tests in the IntegerFunctionTest test case.

// Tests Factorial()
TEST_F(IntegerFunctionTest, Factorial) {
  // Tests factorial of negative numbers.
  EXPECT_EQ(1, Factorial(-5));
  EXPECT_EQ(1, Factorial(-1));
  EXPECT_GT(Factorial(-10), 0);

  // Tests factorial of 0.
  EXPECT_EQ(1, Factorial(0));

  // Tests factorial of positive numbers.
  EXPECT_EQ(1, Factorial(1));
  EXPECT_EQ(2, Factorial(2));
  EXPECT_EQ(6, Factorial(3));
  EXPECT_EQ(40320, Factorial(8));
}

// Tests IsPrime()
TEST_F(IntegerFunctionTest, IsPrime) {
  // Tests negative input.
  EXPECT_FALSE(IsPrime(-1));
  EXPECT_FALSE(IsPrime(-2));
  EXPECT_FALSE(IsPrime(INT_MIN));

  // Tests some trivial cases.
  EXPECT_FALSE(IsPrime(0));
  EXPECT_FALSE(IsPrime(1));
  EXPECT_TRUE(IsPrime(2));
  EXPECT_TRUE(IsPrime(3));

  // Tests positive input.
  EXPECT_FALSE(IsPrime(4));
  EXPECT_TRUE(IsPrime(5));
  EXPECT_FALSE(IsPrime(6));
  EXPECT_TRUE(IsPrime(23));
}

同样地，在只修改组件名，而不修改用例内容情况下，利用夹具类QuickTest的派生类QueueTest实现对Queue的时间性能测试 + 功能测试.

// sample5_unittest.cc

// The next test case (named "QueueTest") also needs to be quick, so
// we derive another fixture from QuickTest.
//
// The QueueTest test fixture has some logic and shared objects in
// addition to what's in QuickTest already.  We define the additional
// stuff inside the body of the test fixture, as usual.
class QueueTest : public QuickTest {
 protected:
  void SetUp() override {
    // First, we need to set up the super fixture (QuickTest).
    QuickTest::SetUp();

    // Second, some additional setup for this fixture.
    q1_.Enqueue(1);
    q2_.Enqueue(2);
    q2_.Enqueue(3);
  }

  // By default, TearDown() inherits the behavior of
  // QuickTest::TearDown().  As we have no additional cleaning work
  // for QueueTest, we omit it here.
  //
  // virtual void TearDown() {
  //   QuickTest::TearDown();
  // }

  Queue<int> q0_;
  Queue<int> q1_;
  Queue<int> q2_;
};

// Now, let's write tests using the QueueTest fixture.

// Tests the default constructor.
TEST_F(QueueTest, DefaultConstructor) { EXPECT_EQ(0u, q0_.Size()); }

// Tests Dequeue().
TEST_F(QueueTest, Dequeue) {
  int* n = q0_.Dequeue();
  EXPECT_TRUE(n == nullptr);

  n = q1_.Dequeue();
  EXPECT_TRUE(n != nullptr);
  EXPECT_EQ(1, *n);
  EXPECT_EQ(0u, q1_.Size());
  delete n;

  n = q2_.Dequeue();
  EXPECT_TRUE(n != nullptr);
  EXPECT_EQ(2, *n);
  EXPECT_EQ(1u, q2_.Size());
  delete n;
}
}  // namespace

小结

利用夹具类testing::Test的派生类，不仅可以为测试对象初始化数据，还能利用其Setup(),TearDown()自动执行特性用来判断用例的时间性能.
对测试人员的代价，仅仅是修改测试组件名，而不用修改测试用例内容.

注意：测的是一个测试用例执行时间，而不是每个待测对象的方法的执行时间.