gtest 学习之二测试函数功能

这是一个使用gtest测试框架的简单例子， 是gtest中给出的例子，用于测试函数的功能。

头文件sample1.h

#ifndef GTEST_SAMPLE1_H_
#define GTEST_SAMPLE1_H_
// Returns n! (the factorial of n).  For negative n, n! is defined to be 1.
int Factorial(int n);

// Returns true iff n is a prime number.
bool IsPrime(int n);

#endif // GTEST_SAMPLE1_H_

实现文件sample1.cpp

#include "sample.h"


// 返回 n! (the factorial of n).  对于负数, n! 被定义为 1.
int Factorial(int n) {
    int result = 1;
    for (int i = 1; i <= n; i++) {
        result *= i;
    }

    return result;
}

// 如果是素数则返回 true
bool IsPrime(int n) {
    // Trivial case 1: 小于1的数
    if (n <= 1) return false;

    // Trivial case 2: 偶数
    if (n % 2 == 0) return n == 2;

    // 当n是倚数且n > 3时
    // 试着从3开始用倚数去除n
    for (int i = 3; ; i += 2) {

 

// 只有试到n的平方根即可
        if (i > n/i) break;

        //如果能被i整除则不是素数.
        if (n % i == 0) return false;
    }

    //n不能被(1~n)范围内的数整除
    return true;
}

main.cpp中的代码：

#include "gtest/gtest.h"
#include "sample.h"



TEST(FactorialTest, Negative) {
    // This test is named "Negative", and belongs to the "FactorialTest"
    // test case.
    EXPECT_EQ(1, Factorial(-5));
    EXPECT_EQ(1, Factorial(-1));
    EXPECT_TRUE(Factorial(-10) > 0);

}

// Tests factorial of 0.
TEST(FactorialTest, Zero) {
    EXPECT_EQ(1, Factorial(0));
}

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

// Tests negative input.
TEST(IsPrimeTest, Negative) {
    // This test belongs to the IsPrimeTest test case.

    EXPECT_FALSE(IsPrime(-1));
    EXPECT_FALSE(IsPrime(-2));
    EXPECT_FALSE(IsPrime(INT_MIN));
}

// Tests some trivial cases.
TEST(IsPrimeTest, Trivial) {
    EXPECT_FALSE(IsPrime(0));
    EXPECT_FALSE(IsPrime(1));
    EXPECT_TRUE(IsPrime(2));
    EXPECT_TRUE(IsPrime(3));
}

// Tests positive input.
TEST(IsPrimeTest, Positive) {
    EXPECT_FALSE(IsPrime(4));
    EXPECT_TRUE(IsPrime(5));
    EXPECT_FALSE(IsPrime(6));
    EXPECT_TRUE(IsPrime(23));
}



int main(int argc, char *argv[])
{
    testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}

编译后的运行结果：