Building Test App with Google Test

g++ demo.cpp demo_tests.cpp -I../include -lgtest -lgtest_main -L../ -o demo_tests

CMakeLists.txt

CMakeLists.txt

cmake_minimum_required(VERSION 3.3)
project(demo_tests)

include_directories(include)
link_directories(lib)

set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

set(SOURCE_FILES
demo.cpp
demo.h
demo_tests.cpp)

add_executable(demo_tests ${SOURCE_FILES})

target_link_libraries(demo_tests
debug gtestd optimized gtest
debug gtest_maind optimized gtest_main)

if(MSVC)
foreach(flag_var CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
if(${flag_var} MATCHES "/MD")
string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
endif(${flag_var} MATCHES "/MD")
if(${flag_var} MATCHES "/MDd")
string(REGEX REPLACE "/MDd" "/MTd" ${flag_var} "${${flag_var}}")
endif(${flag_var} MATCHES "/MDd")
endforeach(flag_var)
endif(MSVC)

demo_tests.h

#include "demo.h"
#include "gtest/gtest.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_GT(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(41320, Factorial(8));
}

// Tests IsPrime()

// 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));
}

demo.h

#ifndef GTEST_SAMPLES_SAMPLE1_H_
#define GTEST_SAMPLES_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_SAMPLES_SAMPLE1_H_

demo.cpp

#include "demo.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;
}

// 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 square 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;
}