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 // 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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