使用Google Test的一个简单例子

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0.
引子


本例是从
gtest-1.5.0
自带的
sample
中的
sample1
改写而来，笔者只添加了一个求
n
的阶层的函数，如下。

void
Factorial(int
n, int
&
result
)
{

result = 1;

for
(int
i = 1; i <= n; i++)

result *= i;
}

目的是想测试像这样将返回值放在参数中返回的函数。
对于该函数，添加的单元测试代码如下。

TEST
(FactorialTest
, Mytest
)
{

int
result = 0;

Factorial
(5, result);

EXPECT_EQ
(120, result);
}

1.
要测试的代码


要测试的代码
(Sample.h)
代码如下。

/**
 * GoogleTest test
 * platform: win32, visual studio 2005/2010; Linux, gcc4.1.2
 */
#ifndef _SAMPLE_H_
#define _SAMPLE_H_
// Returns n! (the factorial of n).  For negative n, n! is defined to be 1.
int Factorial(int n);
void Factorial(int n, int &result);
// Returns true iff n is a prime number.
bool IsPrime(int n);
#endif

要测试的代码
(Sample.cpp)
代码如下。

/**
 * GoogleTest test
 * platform: win32, visual studio 2005/2010; Linux, gcc4.1.2
 */
#include "sample.h"
// Returns n! (the factorial of n).  For negative n, n! is defined to be 1.
int Factorial(int n)
{
    int result = 1;
    for (int i = 1; i <= n; i++)
        result *= i;
    return result;
}
void Factorial(int n, int &result)
{
    result = 1;
    for (int i = 1; i <= n; i++)
        result *= i;
}

// Returns true iff n is a prime number.
bool IsPrime(int n)
{
    // Trivial case 1: small numbers
    if (n <= 1)
        return false;
    // Trivial case 2: even numbers
    if (n % 2 == 0)
        return n==2;
    // Now, we have that n is odd and n >= 3.
    // Try to divide n by every odd number i, starting from 3
    for (int i = 3; ; i += 2)
    {
        // We only have to try i up to the squre root of n
        if (i > n/i)
            break;
        // Now, we have i <= n/i < n.
        // If n is divisible by i, n is not prime.
        if (n % i == 0)
            return false;
    }
    // n has no integer factor in the range (1, n), and thus is prime.
    return true;
}

2.
单元测试代码


单元测试代码
(test.cpp)
如下。

/**
 * GoogleTest test
 * platform: win32, visual studio 2005/2010; Linux, gcc4.1.2
 */
#include "sample.h"
#include <gtest/gtest.h>
// Step 2. Use the TEST macro to define your tests.
// Tests Factorial().
// Tests factorial of negative numbers.
// Test Case name is FactorialTest, Test name is Negative
TEST(FactorialTest, Negative)
{
    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));
}
TEST(FactorialTest, Mytest)
{
    int result = 0;
    Factorial(5, result);
    EXPECT_EQ(120, result);
}
// Tests IsPrime()
// Tests negative input.
TEST(IsPrimeTest, Negative)
{
    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));
}

// Step 3. Call RUN_ALL_TESTS() in main().
//
// We do this by linking in src/gtest_main.cc file, which consists of
// a main() function which calls RUN_ALL_TESTS() for us.
//
// This runs all the tests you've defined, prints the result, and
// returns 0 if successful, or 1 otherwise.
//
// Did you notice that we didn't register the tests?  The
// RUN_ALL_TESTS() macro magically knows about all the tests we
// defined.  Isn't this convenient?

3.
编译


3.1 Linux
平台


makefile
文件，请参考
“
Linux平台如何编译使用Google test写的单元测试？
”


3.2 Win32
平台


Make.bat
文件，请参考
“
Win32
平台如何编译使用
Google test
编
写的单元测试？
”

。


4.
运行结果


4.1 Linux
平台


运行结果如下。

# ./test
Running main() from gtest_main.cc
[==========] Running 7 tests from 2 test cases.
[----------] Global test environment set-up.
[----------] 4 tests from FactorialTest
[ RUN
] FactorialTest.Negative
[
OK ] FactorialTest.Negative (0 ms)
[ RUN
] FactorialTest.Zero
[
OK ] FactorialTest.Zero (0 ms)
[ RUN
] FactorialTest.Positive
[
OK ] FactorialTest.Positive (0 ms)
[ RUN
] FactorialTest.Mytest
[
OK ] FactorialTest.Mytest (0 ms)
[----------] 4 tests from FactorialTest (0 ms total)

[----------] 3 tests from IsPrimeTest
[ RUN
] IsPrimeTest.Negative
[
OK ] IsPrimeTest.Negative (0 ms)
[ RUN
] IsPrimeTest.Trivial
[
OK ] IsPrimeTest.Trivial (0 ms)
[ RUN
] IsPrimeTest.Positive
[
OK ] IsPrimeTest.Positive (0 ms)
[----------] 3 tests from IsPrimeTest (0 ms total)

[----------] Global test environment tear-down
[==========] 7 tests from 2 test cases ran. (0 ms total)
[
PASSED
] 7 tests.

7
个测试均通过。


4.2 Win32
平台


运行结果如下。






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